Ecology of the West Rosebud and Stillwater bighorn sheep herds, Beartooth Mountains, Montana
by Shawn Thomas Stewart
A thesis submitted in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE
in Fish and Wildlife Management
Montana State University
© Copyright by Shawn Thomas Stewart (1975)
Abstract:
A study was conducted in the West Rosebud and Stillwater drainages of the Beartooth Mountains,
southcentral Montana, during the summer of 1974 and the winter and spring of 1975 to obtain
quantitative data on populations, range use, food habits and movements of bighorn sheep in these areas.
Eleven major habitat types and twelve subtypes were recognized. Canopy-coverages and frequencies of
occurrence were determined for low growing plant taxa in each habitat type and/or subtype. Recent
trends in total numbers of bighorn sheep on both the West Rosebud and Stillwater ranges during spring
appeared directly related to the numbers of lambs produced and surviving through winter. Lamb:ewe
ratios were 64:100 during the summers of 1973 and 1974 on the West Rosebud, but lamb mortalities in
excess of 80 percent during the subsequent winters resulted in a declining population. The Stillwater
population has generally increased since 1972 with lamb:ewe ratios ranging from 41:100 to 60:100
during winter and spring. West Rosebud bighorns appeared to lamb during the last week of June and
the first week of July, nearly one month later than is thought to be "normal" for bighorns. During
winter West Rosebud bighorns ranged on high alpine plateaus and were restricted to small windswept
areas of the Cavex/Podi h.t. where relatively little forage of low nutritional value was available. In
April these bighorns migrated down to the steep valley slopes along West Rosebud Creek, dominated
by the Avtv subtype (Pipo/Feid h.t.), where forage of high nutritional quality was available. Stillwater
bighorns spent the winter and spring in the valley bottom using various habitat types where forage of
high nutritional quality was relatively abundant. Inferior horn growth, higher lungworm larval output
and high lamb mortality on the West Rosebud probably reflected these differences in range use and
forage conditions on the two areas. Food habits were determined from feeding site examination and
supplemented by rumen analyses. Dried forbs dominated the bighorns diet on the primary West
Rosebud winter range. On the Stillwater preferred grasses comprised most of the winter diet, though
forbs and browse plants were also used. Grasses dominated the spring diet on both areas. Grasses, forbs
and browse was the order of importance of forage classes used by West Rosebud bighorns during
summer and fall. Mule deer generally used the same habitat types as bighorn sheep on the two areas,
but there was little overlap in food habits between these two species. Mountain goats generally used the
same habitat types and forage species as bighorns. Food habits of horses, cattle and domestic sheep
overlapped significantly with those of bighorn sheep. 
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Signatu
Date
ECOLOGY OF THE WEST ROSEBUD AND STILLWATER 
BIGHORN SHEEP HERDS,
BEARTOOTH MOUNTAINS, MONTANA
BV
SHAWN THOMAS STEWART
A thesis submitted in partial fulfillment 
of the requirements for the degree
of
MASTER OF SCIENCE 
in
Fish and Wildlife Management
Head, Major Department
Graduate Dean
MONTANA STATE UNIVERSITY 
Bozeman, Montana
December 1975
iii
ACKNOWLEDGMENT
To the following, among others, the author wishes to express his 
sincere appreciation for their contributions to this study: Dr. Richard
J. Mackie, Montana State University, who aided in the preparation of the 
manuscript and who, along with Dr. Don C. Quimby, Montana State Univer­
sity, directed the study; Drs. Robert L. Eng and William R. Gould, 
Montana State University, for reviewing the manuscript; Dr. John H. 
Rumely, Montana State University, for aid in identification of plant 
specimens; Dr. David E. Worley, Montana State University, for lungworm 
larvae analyses; Dr. James A. Heimbach, Montana State University, for 
use of equipment; Mr. H. 0. Compton, Montana Department of Fish and 
Game, for initial project planning, technical advice and assistance; 
Messers. Ronald P. Stoneberg, Greg L. Pallister and Jeff Denton,
Montana Department of Fish and Game personnel, for use of their data 
of October and November 1974, and for field assistance and technical 
advice; Mr. Floyd Gordon, Montana Department of Fish and Game, for 
technical advice and assistance; Mr. Kenneth R. Greer, Montana Depart­
ment of Fish and Game, for use of lab facilities; personnel of the 
Beartooth Division, Custer National Forest, for use of facilities; 
Messers. William Henderson, Glenn McKenzie, Thomas Frost, Charles 
Scherzberg, Dewey Whited and Henry Bedford, area landowners, for their 
hospitality and assistance; and to Messers. Phil Huck and Rudy Williams, 
Managers of the Mystic Lake Power Plant, for advice and assistance.
iv
The author would also like to extend a very special thanks to his wife, 
Cheryl, for her constant field companionship and assistance, and for her 
encouragement, understanding and patience. The author was supported by 
the Montana Department of Fish and Game under Federal Aid Project 
W-120-R during this study.
VTABLE OF CONTENTS
V I T A ................     ii
ACKNOWLEDGMENT..................   ill
LIST OF TABLES .................................................  vii
LIST OF FIGURES. . . . . . . . •. . . . . . . . . . . . . . .  . . xii
ABSTRACT........ .. . . ......................... .. xiii
INTRODUCTION . . . . . . . . . . . . .  ..........  I
METHODS. . . . . .  ..................     2
DESCRIPTION OF AREA. . . . . . . . .  ..............  . ........  5
Vegetation.......... .. . . . .............................  10
West Rosebud Area....................................   19
Stillwater Area......................................   25
Historical Bighorn Sheep Populations and Trends ..........  30
Hunting Seasons....................     32
Land Use. ...........................  33
RESULTS..........    36
Population Trends and Dynamics. . ..................   36
West Rosebud Area................    36
Population Trends ......................   36
Lamb Production and Survival. . . ............... 36
Sex Composition ..........  . . . . . . . . . . .  39
Stillwater Area......................................   41
Population Trends ....................    41
Lamb Production and Survival....................  41
Sex Composition................................  43
Seasonal Distribution and Movements ......................  46
West Rosebud Area.............. . . ................. 46
Winter........................ .. . . .  ........  46
Spring. ..........  . . . . . . . .  ............  47
Summer......................   49
Fall. . . . . . . .  ............  51
Stillwater Area..............   51
Winter..........     51
Spring........ .. . ............................. 52
TABLE OF CONTENTS 
(Continued)
Range U s e ..................................................... 52
Use of Habitat Types...............................  52
West Rosebud Area ................................... 52
Winter.........................    52
Spring ........  . . . . . .  ................ 55
Summer . . . . . . . . . . .  ........  . . . .  55
F a l l ..................................   57
Stillwater Area . . . ........................   57
Winter................ ...................... 57
Spring..........................     58
Distribution of Bighorns According to Physical
Characteristics of Habitat. . . . . . . . . . . . . .  59
Group Characteristics......................................... 63
Food Habits .........................................   67
West Rosebud Area..........................     67
Winter............................   67
Spring...............................      74
Summer............................   74
Fall. . . . . . . . . . . . . . . . . . . . . . . .  75
Stillwater Area..........................     75
Winter.................................   75
Spring. .........................................   78
Quantity and Quality of Winter Range Forage . . . .  ........... 80
Quantity of Forage Available . . . .  ..................  80
Quality of Available Forage Plants . . ................... 83
Measures of Population Quality.................................86
Horn Growth.................. ......................... 86
Lungworm Larvae Output ...........................  88
Duration of Suckling Periods..............   88
Lambing Season....................... ....................... 89
Range Use and Food Habits of Other Ungulates.................. 92
Mule Deer................................................. 92
Mountain Goats................................  96
Domestic Livestock ..................................... 97
Horses................   97
Cattle........................ .................... 101
Domestic Sheep.........................    101
DISCUSSION AND CONCLUSIONS . ...............................  102
LITERATURE CITED .......................................  108
APPENDIX............ .. . . ..................................... 114
vi
vii
LIST OF TABLES
Table Page
1. Temperature, precipitation, and snowfall of the West
Rosebud and Stillwater drainages during 1974 and 1975 . . . .  8
2. Average monthly wind speeds (in miles per hour) of
the West Rosebud and Stillwater drainages in 1975 ..........  9
3. Mean percentage canopy coverage and frequency of grasses, 
forbs and low shrubs present in greater than trace 
amounts on habitat types and subtypes on the West Rosebud 
summer range as determined by examination of twenty 2x5 
decimeter plots in each site. Numbers of sites examined
are in parentheses . ....................................... 11
4. Mean percentage canopy coverage and frequency of grasses,
forbs and low shrubs present in greater than trace 
amounts on habitat types and subtypes on the West Rosebud 
winter and spring range as determined by examination of 
twenty 2x5 decimeter plots in each site. Numbers of sites 
examined are in parentheses . . . . . . . . . . .  ..........  15
5. Mean percentage canopy coverage and frequency of grasses, 
forbs and low shrubs present in greater than trace 
amounts on habitat types and subtypes on the Stillwater 
winter range as determined by examination of twenty 2x5 
decimeter plots in each site. Numbers of sites examined
are in parentheses . ........................... .. 17
6. Sex and age composition of the West Rosebud bighorn sheep 
population, as determined from 1,355 multiple observa­
tions and monthly maximum unduplicated observations . . . . . 37
7. Sex and age composition of the Stillwater bighorn sheep
population, as determined from 4,159 multiple observa­
tions and monthly maximum unduplicated observations ........  42
8. Age classes of all rams present on the Stillwater winter 
range from 1971 to 1975. (Table modified from Stoneberg 
1974) 44
viii
LIST OF TABLES
(Continued)
9. Pooled standard diameters, average distances between 
consecutive relocations and average maximum distances 
from winter range centers of activity of bighorn sheep 
on the West Rosebud and Stillwater areas during the 
study period................................    48
10. Percent of 1,343 observations of bighorn sheep of the 
West Rosebud herd in various habitat types by month and
season............    53
11. Percent of 3,920 observations of bighorn sheep of the 
Stillwater herd in various habitat types by month and
season..................   54
12. Percent distribution of bighorn sheep observations accord­
ing to physical characteristics of the habitat based on 
multiple observations of individuals of the West Rosebud 
population ........................  ........  . . . . . . .  60
Table Page
13. Percent distribution of bighorn sheep observations accord­
ing to physical characteristics of the habitat based on 
multiple observations of individuals of the Stillwater 
population........................    61
14. Relationship of mean bighorn sheep group size and distance 
from escape cover by season on the Stillwater and West
Rosebud areas.  ...............    64
15. Relationship of mean bighorn sheep group size and habitat
type occupation on the Stillwater area during winter and 
spring, 1975 . . . .  ......................................  65
16. Relationship of mean bighorn sheep group size and habitat
type occupation by season on the West Rosebud a r e a ........ . 66
17. Mean percentages of use (U) and preference indices (?) by 
habitat type and/or subtype for each plant species used
by bighorn sheep in greater than trace amounts in at least 
one type during each season in the West Rosebud area. Trace 
(Tr) amounts are less than 1.0 percent. Numbers of feeding 
sites examined and instances of use are shown in parentheses. 68
rLIST OF TABLES 
(Continued)
Table Page
18. Mean volume percentage of each plant taxon and forage
class which occurred in bighorn sheep rumen samples collected 
in fall, winter, and spring since 1972 for the West Rosebud 
and Stillwater areas. Trace (Tr) amounts are less than 1.0 
percent. Numbers of samples are shown in parentheses . . . .  71
19. Mean percentages of use (U) and preference indices (P) by 
habitat type and/or subtype for each plant species used by 
bighorn sheep in greater than trace amounts in at least one 
type during winter and spring, 1975 in the Stillwater area.
Trace (Tr) amounts are less than 1.0 percent. Numbers of 
feeding sites examined and instances of use are shown in
parentheses........ .. . . . . ............... . . . . . . . 72
20. Relationship of snow conditions to mean percentage forage •
class utilization by bighorn sheep in each habitat type
and/or subtype on the Stillwater area from January to June 
1975 ........  79
21. Standing crop of bighorn sheep forage species available at
the end of the winter period, 1975, on Stillwater and West 
Rosebud habitat types ...................... .. 81
22. Differences of standing crops (lbs./acre) of bighorn forage
species available during March and April, 1975, on Stillwater 
and West Rosebud habitat types. . . ..................... „ . 82
23. Mean percentage protein content of major bighorn forage
species from the Stillwater and West Rosebud areas. . . . . .  84
24. Mean length of annual horn growth segments and mean
circumference at annual rings of bighorn rams from the
West Rosebud and Stillwater populations . . . . . . . . . . .  87
25. Estimated birth dates of newborn lambs observed on the 
West Rosebud drainage during the early summers of 1974
and 1975. . . . . . . . . . . . . . . . . . . . . . . . . . .  90
26. Progression of isolation of ewes prior to lambing in 1975
on the West Rosebud drainage. ................... 90
XLIST OF TABLES
(Continued)
27. Percent of 718 observations of mule deer in various
habitat types during winter and spring 1975 in the West 
Rosebud area ................................. .. ........... 92
Table Page
28. Mean percentage of use (U) and preference indices (P) by 
habitat type and/or subtype of each plant species used by 
mule deer during winter and spring, 1975» in the Stillwater 
and West Rosebud areas. Trace (Tr) amounts are less than 
0.5 percent. Numbers of feeding sites examined and instances
of use are shown in parentheses.............. .. 93
29. Percent of 1,656 observations of mule deer in various
habitat types during winter and spring 1975 in the Still­
water a r e a .................... ............................  95
30. Percent of 216 observations of mountain goats in various
habitat types during the summer of 1974 and the winter and 
spring of 1975 .......................... ..................  96
31. Mean percentage of use of each plant species used by 
mountain goats during summer and fall 1974 and spring 
1975. Trace (Tr) amounts are less than 0.5 percent.
Numbers of feeding sites examined and instances of use are 
shown in parentheses........ ..............................  98
32. Mean percentage of use (U) and preference indices (P) of
each plant species used by horses, cattle and domestic 
sheep in various seasons and habitat types. Trace (Tr) 
amounts are less than 0.5 percent. Numbers of feeding sites 
examined and instances of use are shown in parentheses . . .  99
33. Actual counts and population estimates of Stillwater bighorn
sheep prior to 1971........................ ................ 115
34. Statistics of bighorn sheep hunting in the Beartooth
Mountains, 1953-1974 ........ ..............................116
35. Statistics of grazing allotments on important bighorn 
sheep range, 1911-1946 . ......................  . 117
36. Monthly and seasonal centers of activity, standard
diameters, maximum distances from winter range centers 
of activity and average distance between consecutive 
relocations for marked West Rosebud bighorns ........ .. 118
37. Monthly and seasonal centers of activity, standard
diameters, maximum distances from winter range centers 
of activity and average distance between consecutive 
relocations for marked Stillwater bighorns . ........... , . 120
38. Locations of five lambing areas on the West Rosebud
drainage during the springs of 1974 and 1975 ........ .. 123
39. Mean percentages of use by month and season of each plant 
species used by bighorn sheep in the West Rosebud area.
Trace (Tr) amounts are less than 0.5 percent. Numbers of 
feeding sites examined and instances of use are shown in 
parentheses........................................... 124
40. Mean percentage of use by month and season of each plant 
species used by bighorn sheep in the Stillwater area. Trace 
(Tr) amounts are less than 0.5 percent. Numbers of feeding 
sites examined and instances of use are shown in parentheses. 127
xi
LIST OF TABLES
(Continued)
Table Page
xii
LIST OF FIGURES
Figure Page
I. Map of the study area showing the distribution of
bighorn sheep of the West Rosebud and Stillwater areas 
by season ..........  ..................  . . . . . . 6
xiii
ABSTRACT
A study was conducted in the West Rosebud and Stillwater drainages 
of the Beartooth Mountains, southcentral Montana, during the summer of 
1974 and the winter and spring of 1975 to obtain quantitative data on 
populations, range use, food habits and movements of bighorn sheep in 
these areas. Eleven major habitat types and twelve subtypes were 
recognized. Canopy-coverages and frequencies of occurrence were deter­
mined for low growing plant taxa in each habitat type and/or subtype. 
Recent trends in total numbers of bighorn sheep on both the West Rosebud 
and Stillwater ranges during spring appeared directly related to the 
numbers of lambs produced and surviving through winter. Lamb:ewe ratios 
were 64:100 during the summers of 1973 and 1974 on the West Rosebud, but 
lamb mortalities in excess of 80 percent during the subsequent winters 
resulted in a declining population. The Stillwater population has 
generally increased since 1972 with lamb:ewe ratios ranging from 41:100 
to 60:100 during winter and spring. West Rosebud bighorns appeared to 
lamb during the last week of June and the first week of July, nearly 
one month later than is thought to be "normal" for bighorns. During 
winter West Rosebud bighorns ranged on high alpine plateaus and were 
restricted to small windswept areas of the Carex/Vodi h.t. where 
relatively little forage of low nutritional value was available. In 
April these bighorns migrated down to the steep valley slopes along 
West Rosebud Creek, dominated by the Avtv subtype (Pipo/Feid h.t.), where 
forage of high nutritional quality was available. Stillwater bighorns 
spent the winter and spring in the valley bottom using various habitat 
types where forage of high nutritional quality was relatively abundant. 
Inferior horn growth, higher lungworm larval output and high lamb 
mortality on the West Rosebud probably reflected these differences in 
range use and forage conditions on the two areas. Food habits were 
determined from feeding site examination and supplemented by rumen 
analyses. Dried forbs dominated the bighorns diet on the primary West 
Rosebud winter range. On the Stillwater preferred grasses comprised 
most of the winter diet, though forbs and browse plants were also used. 
Grasses dominated the spring diet on both areas. Grasses, forbs and 
browse was the order of importance of forage classes used by West 
Rosebud bighorns during summer and fall. Mule deer generally used the 
same habitat types as bighorn sheep on the two areas, but there was 
little overlap in food habits between these two species. Mountain 
goats generally used the same habitat types and forage species as 
bighorns. Food habits of horses, cattle and domestic sheep overlapped 
significantly with those of bighorn sheep.
INTRODUCTION
Populations of Rocky Mountain bighorn sheep (Ovis canadensis 
canadensis Shaw) winter in several distinct areas in the Beartooth 
Mountains of south central Montana. The principle wintering areas 
include main Rock Creek, West Rosebud Creek, and the main Stillwater 
River. Until recently, available information on these bighorns was 
limited to occasional counts on winter ranges and examination of a few 
scattered feeding sites (Pallister 1974).
Coordinated studies of bighorns in the West Rosebud and Stillwater 
drainages was initiated in 1971. Stoneberg (1973, 1974) studied repro­
duction and the. incidence of lungworm among bighorns as well as utiliza 
tion of grasses on winter range from 1971 to 1974, while Pallister 
(1974) studied population composition, movements, range use and food 
habits during the summer and fall of 1973.
The present study extended the latter investigation through the 
summer of 1974 and the winter and spring of 1975. In addition, total 
standing crop of forage and the protein content of principle forage 
species were determined to evaluate possible effects on the bighorn 
sheep populations.
METHODS
Twenty-seven bighorn sheep were individually marked between the 
spring of 1973 and the spring of 1975 by Montana Department of Fish and 
Game biologists using a "cap-chur" gun. Sixteen were marked on the 
Stillwater River and 11 on West Rosebud Creek. Each sheep was fitted 
with a neckband which was color-coded as to area of capture, and tagged 
in the right ear with a numbered metal tag and in the left ear with a 
plastic cattle tag embossed with black numerals.
Several methods were used to locate marked as well as unmarked 
bighorn sheep. During summer, most observations were made by backpack­
ing to back country camps from which daily observational trips were 
made. When sheep were at lower elevations, observations were made from 
a vehicle. Nine and five flights in fixed-wing aircraft, were made 
during summer and winter, respectively. In addition, one helicopter 
flight was made during the winter period to gain access to the other­
wise inaccessible West Rosebud winter range, and two helicopter flights 
were made during the spring period in an effort to locate lambing areas.
Information recorded at each bighorn observation site included the 
location, time of day, temperature, estimated wind velocity, habitat 
type, distance to escape cover, elevation as determined from U.S.G.S. 
quadrangle maps, and an estimate of degree of slope. The bighorns were 
classified as to age, sex, activity and whether marked or unmarked.
—3—
Similar data were recorded for all observations of mule deer (Odoooiteus 
henvionus) and mountain goats (Oreamnos americanus) to evaluate possible 
Interactions between these species and bighorn sheep.
All bighorn rams were classified as to the degree of horn curl 
(1/4 or less, 1/4 to 1/2, 1/2 to 3/4, or 3/4+). Whenever possible, I 
attempted to further "age" rams with less than 3/4-curl by counting 
horn segments (Geist 1966).
Vegetation of the study area was classified by habitat type and/or 
subtype. Vegetation of representative areas within each type used by 
bighorn sheep was quantitatively sampled using the canopy-coverage 
method (Daubenmire 1959). Canopy-coverage and frequency of occurrence 
of plant species less than one meter tall were obtained by examination 
of twenty 2x5 decimeter plots located at five foot intervals along a 
line transect. A plant collection was compiled to aid in recognition 
of species. Plant nomenclature follows Booth (1950) and Booth and 
Wright (1966).
The amount of forage available to the sheep at the end of the 
winter period was determined for each habitat type or subtype. Esti­
mates were made by clipping all herbaceous plants to ground level and 
stems up to five mm. in diameter of all browse species from twenty 
2x5 decimeter plots in each habitat type. Forage collections were 
made at the same time as the canopy-coverage transects were read. An . 
equal number of plots was clipped from each of the transects within a
-4-
habitat type for the total of twenty plots. Forage was oven dried and 
the standing crop calculated on a dry weight basis.
Food habits of bighorn sheep were determined by examination of 
feeding sites (Cole 1956). Similar data were gathered for mule deer, 
mountain goats and domestic livestock to determine if forage competi­
tion existed between these species and bighorns. An estimation of one 
bite was considered to represent one instance of use. Rumen samples 
collected from bighorns killed in tagging operations as well as from 
one illegally killed bighorn ram provided supplementary data. Analysis 
of data of both feeding site examinations and rumen analyses followed 
the mean percentage method of Martin et al. (1946). A preference index 
of each forage species was calculated according to the method described 
by Peterson (1970).
One-gram samples of each major bighorn sheep forage species were 
collected from each of the most important habitat types and/or subtypes 
for determination of crude protein content. The two periods of sample 
collection were mid-winter (late February) and late winter (mid-April). 
Chemical analyses were conducted by the Montana State University 
Analytical Chemistry Laboratory, Bozeman.
Fecal samples were collected throughout the winter and spring 
periods to determine the incidence and intensity of lungworm 
(Protostrongylus spp.) infestations. Analyses were conducted by the 
Montana State University Veterinary Laboratory, Bozeman.
DESCRIPTION OF AREA
The study was conducted on a 300 square mile area located approxi­
mately 75 miles southwest of Billings, Montana (Pallister 1974). 
Boundaries were a line including the Boulder River, Sheepherder Peak 
and Cutoff Mountain on the west, the Red Lodge - Cooke City highway on 
the east, the Montana - Wyoming border and Yellowstone National Park 
boundary on the south, and the West Fork of the Stillwater River and 
the border of the Custer National Forest on the north (Fig. I). 
Approximately one-half of the area was within the Beartooth Primitive 
Area.
Topographically, the study area was extremely diverse. Elevations 
ranged from approximately 5,000 feet on the Stillwater winter range to 
12,799 feet at Granite Peak, the highest peak in Montana. A large part 
of the area consisted of alpine plateaus, rising gradually from 9,800 
feet to nearly 12,000 feet. The plateaus are broken by numerous 
glacially carved canyons which commonly drop 2,000 feet or more to snow 
fed lakes and streams. Slopes along these canyons vary from 50 to more 
than 75 degrees. To the north and east the canyons and ridges termi­
nate in grass and timber covered foothills; to the south and west they 
are continuous with the more gentle alpine areas adjoining the timbered 
plateaus of Yellowstone Park described by Meagher (1973).
Figure I. Map of the study area showing the distribution of bighorn sheep of the West 
Rosebud and Stillwater areas by season.
-7
The geology of the Beartooth block is described in detail in 
studies published by the Billings Geological Society (1958).
Weather data, generally indicative of weather conditions of the 
area (Table I), were obtained from the U. S. Weather Bureau Station at 
the Mystic Lake Power Plant at an elevation of 6,558 feet in the West 
Rosebud drainage. In addition, I recorded temperatures at an elevation 
of approximately 5,250 feet in the Stillwater drainage using a 
hygrothermograph. The mean temperature of 42.1 F. at Mystic Lake during 
1974 was only slightly higher than the normal 41.6 F. (U. S. Department 
of Commerce Weather Bureau 1974). There were no consistent differences 
from the normal in monthly trends. Mean temperatures for each of the 
first six months of 1975 were consistently lower than normal (U. S. 
Department of Commerce Weather Bureau 1975). Mean monthly temperatures 
in the Stillwater for early 1975 were generally warmer than the 
corresponding temperatures of the West Rosebud, probably due to the 
lower elevation of the Stillwater area. Total precipitation at Mystic 
Lake in 1974 was 31.32 inches, or considerably more than the normal 
25.67 inches (Table I). All of the first six months of 1975, except 
April, showed greater than normal precipitation. Although total 
monthly precipitation in 1975 was greater than that of 1974 for only 
three of the first six months, total snowfall during 1975 was substan­
tially greater in all months except March and June (Table I). Snowfall
Table I. Temperature, precipitation, and snowfall of the West Rosebud and Stillwater Drainages^ 
during 1974 and 1975.
Temperatures (0F) Precipitation (Inches) Snowfall (Inches)
Mystic
Lake
Normal2
Mystic
Lake
1974
Mystic
Lake
1975
Stillwater
1975
Mystic
Lake
Normal
Mystic
Lake
1974
Mystic
Lake
1975
Mystic
Lake
1974
Mystic
Lake
1975
January 24.0 20.0 22.3 26.4 1.53 1.44 3.01 14.0 39.1
February 26.4 30.2 22.6 28.6 1.20 0.56 1.36 9.0 18.0
March 28.4 29.4 26.2 31.2 2.28 3.37 2.37 43.0 32.0
April 37.9 41.2 29.6 37.4 3.07 3.30 2.60 23.5 33.5 ,
May 46.7 42.8 42.7 47.4 3.47 4.93 4.46 19.5 58.0 ”
June 53.7 59.0 52.2 : 3.57 3.62 4.41 10.0 Tr
July 62.6 64.9 1.97 2.74
August 61.8 56.9 1.81 2.45
September 52.7 51.0 2.34 1.88 10.0
October 45.0 47.0 1.55 5.64 29.5
November 32.9 33.7 1.70 0.62 6.5
December 27.2 28.6 1.18 0.77 9.5
Annual Mean 
or Total
41.6 42.1 25.67 31.32
1Only temperature data available for Stillwater drainage. 
^Normals computed from 1941-1970 data.
-9-
in 1975 was also greater than 1974 in the Stillwater drainage 
(R. Stoneberg pers. comm.).
Average monthly wind velocities (Table 2), as recorded with 
anemometers, were considerably greater in the Stillwater area than on 
the West Rosebud. This probably was a major reason why the Stillwater 
winter range was generally free of snow while the West Rosebud canyon 
consistently held at least some snow cover.
Table 2. Average monthly wind speeds (in miles per hour) of the West 
Rosebud and Stillwater drainages in 1975.
West Rosebud Stillwater
January 9.58 13.76
February 9.81 13.69
March 6.11 8.54
April 5.16 19.88
May 4.63 5.60
Although wind data collected previously (1971-74) at the Mouat 
Mine in the Stillwater drainage (Richmand and Adler 1974) were not 
comparable to my data, residents of the area considered the winter of 
1974-75 to be less windy than normal (B. Dowd, W. Henderson, and 
R. Stoneberg pers. comm.).
The combination of lower than average temperatures, higher than 
average snowfall and less wind than normal resulted in greater than 
normal snow depths on the winter ranges during 1974-75.
-10-
Vegetation
General characteristics of the vegetation of the Beartooth Mountains 
have been described by South (1971), who recognized 17 ecosystems on the 
basis of characteristic flora and fauna, and Pallister (1974), who 
quantitatively described the plant communities important to bighorn 
sheep.
To evaluate and describe habitat usage by bighorn sheep, I 
divided the study area into habitat types (hereafter abbreviated h.t.) 
following recent classifications and descriptions of climax forest types 
of Montana (Pfister et al. 1974) where vegetation appeared to be 
climax. Alpine, subalpine and river bottom types not considered by 
Pfister et al. (1974) were designated on the basis of characteristic or 
"dominant" plant species as determined by canopy-coverage. Serai stages 
of the habitat types, as well as areas specifically important to bighorns, 
were recognized as subtypes.
Eleven types and 12 subtypes were recognized on the study area. 
Because the West Rosebud and Stillwater winter ranges were comprised of 
totally different habitat types (Tables 4 and 5), vegetational character­
istics of these two areas are described separately. Species composition, 
canopy-coverage, and frequencies of occurrence of grasses, forbs and 
low shrubs for these types on the West Rosebud summer range, the West 
Rosebud winter range, and the Stillwater winter range are presented in 
Tables 3, 4 and 5, respectively.
Table 3. Mean percentage canopy coverage and frequency of grasses, forbs and low shrubs present
In greater than trace* amounts on habitat types and subtypes on the West Rosebud
summer range as determined by examination of twenty 2x5 decimeter plots In each site.
Numbers of sites examined are In parentheses.
Taxa
Carex/Podi
Climax Rock
(4) (2)
Abla/Vaat2-
Climax Rock
(I) (3)
Abla / 
Vaso
(I)
PtaZ/
Aomi
(2)
Paa/
Trifo
(I)
Grasses and Grass-like
•
Plants
Agropyron oaninum 3/353
Agropyron soribneri Tr/11 1/20
Agropyron spioatum 2/8
Agrostis soabra 2/10 ,
Bromus spp. Tr/ 5
Carex spp. 10/42 1/15 3/18 10/70 8/45
Daotylis glomerata 4/70
Desohampsia atropurpurea 4/55
Desohampsia oaespitosa I/ 6 "
Equisetwn arvense 1/20
Festuoa ovina Tr/10 1/25 Tr/12
Junous baltious 3/50
Koeleria cristata 3/51 Tr/Tr Tr/18
Luzula wahlenbergii Tr/Tr 1/40
Melioa speotabilis ■ Tr/ 5
Phleum alpinum Tr/10 Tr/Tr
Phleum pratensis 1/20
Poa spp. 5/61 10/75 . 1/13 5/60 6/62 33/100
Unknown 1/15 1/15 1/10
Forbs
Achillea millefolium 2/21 3/48 Tr/10 8/78
Agoseris glauoa 1/10 Tr/15 3/72
Table 3. Continued
Car ex/Pod^
Taxa
Climax
(4)
Rock
(2)
Forbs (cont.) 
Antennaria spp. 1/16
Apiaoeae Ir/Tr
Apoaynnm androsaemifolium 
Arnica latifolia 
Artemisia scopulorum 1/6
Aster alpigenus 
Astragalus vexilliflexus 7/50
Brassioaoeae Tr/Tr Tr/ 5
Castillega ousiokii 1/10
Cerastium arvense 5/71 Tr/Tr
Cerastium vulgatum 
Cirsium foliosum I/ 5
Epilobium angustifolium Tr/15
Erigeron spp. 2/39 Tr/Tr
Eriogonum umbellatum 
Fabaoeae 2/24
Fragaria virginiana 
Geum rossii 2/15
Lloydia serotina Tr/Tr 1/20
Lupinus argenteus 4/29
Mertensia alpina 1/20 I/ 8
Mertensia oblongifolia I/ 5
Oxyria digyna 
Flantago spp. 
Folemonium visoosum 3/16
Polygonum bistortoides 1/19 1/20
Abla/Vaal
Climax Rock
(I) (3)
Ahlux/ . 
Vado
u)
PtaZ/
Aomi
(27
Tr/Tr
1/10
2/50 1/12
1/22
6/20 Tr/Tr
Tr/ 5 1/Tr
1/23 1/45 Tr/ 5
1/30
3/55 9/68
1/10
2/15
6/75 3/32
14/72
I/ 5
Tr/15
Poa/
Trifo
(I)
I/ 6
6/55
Table 3. Continued.
Carex/Podi 
Climax Rock
Taxa (4) (2)
Forbs (cont.)
Potentilla diversifolia 4/46 . 4/48
Potentilla spp. 
Seduxn spp. 3/64 1/28
Seneoio aanus
Seneaio orassulus Tr/Tr Tr/Tr
SiZene aaaulis 5/28
Smelowskia aalyaina 2/31
Solidago missouriensis
Solidago spp. 1/10 .
Taraxacum officinale Tr/Tr Tr/ 5
Trifolium parryi 6/50
Trifolium spp. 
Veronica wormskjoldii 
Viola spp.
Unknown 3/49 8/68
Shrubs and Low Trees 
Abies lasioaarpa 
Alnus inaana 
Arctostaphylos uva-ursi 
Berberis repens 
Ceanothus velutinus 
Juniperus communis 
Juniperus horizontalis 
Penstemon fruticosus
Phyllodooe glanduliflora I/ 8
Physoaarpus malvaceus
Ab la / Vaa I Ab La/ Pial /
Climax Rock Vasa Aomi
(I) (3) (I) (2)
Tr/ 5 Tr/Tr
Tr / 8
1/12
1/25 1/32
Tr/18
Tr/ 5
Tr / 5
3/35
Tr/ 5 
1/15 
2/15
I/ 5
Tr/ 7 
Tr/ 5
2/ 3 
3/27 
13/17 
2/Tr 
1/Tr 
3/10
3/ 7
1/40
3/30
I/ 5 
10/40
1/32 
Tr/ 8
Poa/
Trifo
(I)
23/100
51/100
Table 3. Continued.
Cavex/Podi Abla/Vagl AS &z/ PtaZ/ Poa/
Climax Rock Climax Rock Fiasc Aemt Tvifo
Taxa (4) (2) (I) (3) (I) (2) (I)
Shrubs and Low Trees (cont. 
Pinus albicaulis
)
1/5 Tr/ 5
Potentilla frutiaosa 
Pvunus vivginiana
6/25
3/ 8
Ribes setosum ■ 2/Tr
Rosa aciculavis I/ 7
Rubus idaeus Tr / 5
Salix spp.
Vaooinium globulave 
Vaooinium scopavium
1/20
21/65
4/55
I
9/40 I
Unknown 1/10
Fern Tr / 8 1/10 Tr / 5
Lichen Tr/Tr I/ 5
Mosses 3/20 Tr/Tr 2/ 8 5/60
Selaginella densa Tr/Tr 1/Tr
Unknown 3/19 Tr/Tr I/ 5 5/60
Litter 11/58 75/100 1/Tr
Rock 14/29 27/88 3/ 5 21/30 10/10 I/ 5
Soil 16/46 3/12 25/53 12/65 38/92
Grasses and Grass-like 19/94 21/90 2/30 13/73 25/95 16/92 38/100
Plants
Forbs 47/98 38/98 4/40 6/65 24/95 44/100 82/100
Shrubs and Low Trees 3/28 25/80 32/67 25/75
1Trace (Tr) = Canopy coverage less than 0.5 percent or frequency less than 5 percent. 
2First two letters of generic and specific name, e.g. Abla/Vagl=Abies lasiocarpa/Vaaoiniim
Qlobulavei of those species used in naming the habitat type. 
3Canopy coverage/Frequency.
See text.
Table 4. Mean percentage canopy coverage and frequency of grasses, forbs and low shrubs present
in greater than trace1 amounts on habitat types and subtypes on the West Rosebud winter
and spring range as determined by examination of twenty 2x5 decimeter plots in each
site. Numbers of sites examined are in parentheses.
Pioo/Feid A.olaf
Carex/ Artr Vagif Potr/
Podi Climax Piao Rock Burn Rock Syal
Taxa Winter Winter Winter Winter Spring Spring Spring Spring Spring
(I) (I) (i) (4) (5) (I) (I) (3) (2)
Grasses and Grass-like Plants
Agropyron apioatun 2/25z Tr/Tr 5/45 4/44 2/20 4/50 3/33 Tr/ 8
Agropyron spp. 1/12
Carex spp. 18/100 2/44 3/38 Tr/ 5 3/60 2/32
DeBahampeia aaespitoaa Ir/ 5
Featuaa idahoenaia 3/15 3/29 5/43 3/40 14/90 3/45
Featuaa ovina 3/ 55
Heaperoahloa kingii 6/20 6/44 3/23 . 6/25 5/45
Koeleria oriatata Ir/ 5 Tr/Tr
Poa spp. 2/5 Tr/Tr . . 3/15 9/45
Forbs
Aahillea millefolium Tr/Tr Tr/ 5 Tr/Tr Tr/Tr
Agoeeria glauoa Tr/Tr Tr/ 5
Anemone patena Tr/Tr Tr/10
Antennaria spp. Tr/Tr Tr/ 7 1/13
Apiaaeae 1/12
Apooynum androaaemifolium 1/12
Artemieia aampeetrie Tr/15
Artemisia frigida Tr/10 Tr/ 6 1/13 Tr/15 1/25
Aeteraaeae Tr/Tr Tr/ 8 Tr/ 5 Tr/12
Baleamorrhiza eagittata ' Tr/Tr 9/26 6/17 10/25 10/12
Braaaiaaoeae Tr/ 5 Tr/10 Tr/Tr
Ceraetium arvense I/ 15 1/19 Tr/ 5 I/ 5 Tr/15
Chryaopaia villoaa Tr/ 7 Tr/Tr
Comandra umbellata Tr/ 7
Delphinium biaolor Ir/ 8 Tr/ 5 1/20 Tr/Tr
Dodeaatheon conjugens Tr/Tr Tr/ 8
Geum roasii 34/ 95
Heuohera cylindrioa Tr/ 5
Lupinua argenteue 3/18 4/26 5/45 5/12
Nonarda fiatuloea 4/22
Muaineon divarioatun Tr/ 5
Phlox hoodii Ir/ 8 Tr/Tr ‘ 2/50
Ii—1
UlI
Saxifraga spp. I/ 45
Table 4. Continued
Taxa
Carex/
Podi
Winter
(I)
Climax
Winter
(I)
Pioo
Winter
(I)
Pipo/Feid
Artr
Winter Spring 
(4) (5)
Rock
Spring
(I)
Burn
Spring
(I)
XMa/
Vagi!
Rock
Spring
(3)
Potr / 
Syal 
Spring 
(2)
Forbs (cont.)
Silene aeaulis 2/ 10
Tragopogon dubius Tr/Tr Ir/ 5 Tr/Tr Tr/Tr
Viola nuttallii 1/13 1/30
Unknown I/ 40 Tr/Tr Tr/ 8 1/25 Tr/10
Shrubs
Amelanohier alnifolia Tr/10 Tr/12 I/ 8
ArctoetaphyICa uva-urei Tr/ 5
Artemisia tridentata 6/20 32/62 25/49 9/30 1/Tr
Berberie repens I/ 8
Juniperue aormunie 2/Tr 2/Tr
Physooarpue malvaoeue 20/52
Populue tremuloides 3/10
Prunus virginiana Tr/Tr 3/15 12/42
Symphoriaarpos albus 5/28
Fern Tr/Tr 1/18 Tr/Tr
Moss I/ 25 Tr/Tr 4/35 16/50
Selaginella denea I/ 25 4/35 16/50
Litter 73/100 87/95 11/30
Rock 16/ 20 12/50 9/25 8/26 9/30 49/75 8/50 47/87 44/78
Soil 8/ 40 39/74 40/78 19/40 33/90 6/17 4/32
Grasses and Grass-like Plants 21/100 12/ 50 Tr/Tr 19/84 15/76 11/55 27/100 11/68 10/52
Forbs 39/ 95 Tr / 10 Tr / 5 14/64 14/68 2/50 20/100 .3/50 20/55
Shrubs and Low Trees 6/ 20 3/ 5 32/62 25/55 12/45 22/58 22/68
1Trace (Tr) « Canopy coverage less than 0.5 percent/Frequency less than 5 percent. 
2Canopy coverage/Frequency
Table 5. Mean percentage canopy coverage and frequency of grasses, forbs and low shrubs
present In greater than trace1 amounts on habitat types and subtypes on the Stillwater
winter range as determined by examination of twenty 2x5 decimeter plots in each site.
Numbers of sites examined are in parentheses. ______________ . ; ________
______________Feid/Assp___________  ____________________  P a r r a / J l^ g p _____________________ _____ Fa^ e/ . ^otr/ Potv/Salix
Grazed Ungrazed P.htr Artr Rock 'V'SP Climax Feii Sydi Climax Tula
Simimer Winter Winter Winter Winter Winter Winter Winter Winter Winter Winter Winter
T axa (i) (4) (4) (7) (4) (4) (2) (2) (2) (I) (I) Cl)
Grasses and Grasslike
Plants
Agropyvon epioattm 8/582 12/59 18/74 3/26 28/90 7/32 15/92
Agroatie aoobra 16/100
Bromua teotorum 7/20 6/22 Tr/Tr 1/10 . 3/26 Tr/10 Tr/Tr
Cdlomovilfa longifolia Tr/Tr Tr/Tr 2/15 2/10 ' 2/20 Tr/12
Carex spp. 3/40 5/54 3/49 4/40 6/32 Tr/Tr 3/48 1/20 7/45 16/95
Equiaetum arvenae 2/65
Featuaa idahoenaia 2/38 17/96 2/19 I/ 5 Tr/Tr 1/22 I/ 8. 12/78 I
Juncua balticua 2/80 H
Koeleria crietata 5/65 1/35 1/39 Tr/13 2/25 2/42 I
Phleum pvateneie Tr/ 5 7/75
Poa spp. 14/75 10/49 30/37 Tr/Tr Tr/18 87/100 2/50
Stipa eomata 5/70 Tr/14 Tr/ 8 1/10 4/35
Typha latifolia 97/100
Unknown 1/10 Tr/Tr 1/15
Forbs
Allium spp. Tr/ 6 1/58 1/32
Antennaria spp. 1/10 6/39 1/14 Tr/Tr Tr/Tr
Artemiaia campeatrie 2/15 2/26 Tr/ 8 Tr/Tr Tr/Tr Tr/ 5 1/22
Artemiaia frigida 16/85 8/79 2/45 2/36 Tr/Tr Tr/Tr 2/55 Tr/Tr 5/85
Artemiaia ludoviciana 2/20 Tr/Tr 1/22 1/26 1/21 Tr/ 5 Tr/Tr
Aateraoeae Tr/ 5 Tr/Tr Tr/Tr 1/30
Aatragalua spp. 6/35
Balaomorrhiza eagittata 2/10 Tr/Tr I/ 5
Braeaicaoeae 2/35 Tr/ 5
Cetviatium arvenae 2/15 7/45 2/68 Tr/11 1/21 1/15 Tr/ 5 1/42
Chryaopeia villoaa 1/10 1/32 4/59 Tr/ 9 2/12 2/48
Comandra umbellate Tr/ 6
Delphinium bieolor Tr/Tr Tr/Tr Tr/Tr Tr/12 .
Erigeron aaeapitoaua I/ 5 1/10
Fdbaeeae Ir/ 5 Tr/Tr Tr/ 8
Liatria punctata 5/20 Tr/Tr 2/25 Tr/Tr Tr / 5
Table 5. Continued
Taxa
Grazed
Summer Winter 
(I) (4)
2*_______
Ungrazed
Winter
(4)
-
Winter
(7)
Artr
Winter
(4)
Winter 
(4) .
-V-'
Winter
(2)
Climax
Winter
(2)
= V - V
Winter
(2)
-rI-:
Winter
(I)
Climax
Winter
(I)
Winter
(I)
Forbs (cent.)
Luvinue arienteua 2/10
Cpur.tia polyxmt'na ■ • Tr/Tr 1/Tr Tr/ 8
Fhlox hoodii 4/40 7/58 2/52 Tr/Tr 1/18
Tlantago spp. Tr/15
Trifoliun spp. 4/50
Unknown 4/55 1/25 Tr/ 9 Tr/Tr Tr/14 Tr/Tr Tr/Tr
Shrubs and Low Trees -
Artemisia tridentata Tr/Ir 1/Tr 22/34 2/Tr Tr/Tr
herberi-e repens Tr/15
Comus stolonifera 1/Tr
Juniperue cormunie Tr/Tr 1/Tr 2/Tr
Juniperus horizontalis 1/Tr 1/Tr
Physooarpue malvaceus 1/Tr
Populas trenuloides Tr/Tr Tr/Tr 3/ 5
Prunus virqiniana 1/Tr I/ 9 I/ 6 1/Tr 1 / 5 3/25
Pseudotsuga menziesii 1/Tr
Rhus trilobata 5/ 5 11/14 3/ 5 2/ 6
Ribes oereu/n Tr/Tr 1/Tr
Ribes spp. 2/Tr
Rosa acicularis 4/25 2/ 6 1/11 Tr/Tr Tr/Tr 10/35
Salix spp. 4/30
Synphorioatpos albus 1/Tr Tr/ 5 . 3/25
Unknown 1/19 Tr/ 8 Tr/ 5
Lichen I/ 5 3/64 1/41 Tr/ 8 1/20 1/38 ■
Mosses 11/60 11/39 15/51 8/28 Tr/Tr Tr/Tr 11/50 I/ 8 20/70 10/100
Selaginella densa 11/60 11/38 15/51 8/28 Tr/Tr Tr/Tr 11/50 20/70
Unknown Tr / 8 I/ 8 10/100
Litter 76/90 6/40
Rock 6/25 5/18 7/26 8/34 24/56 79/88 10/32 12/35 4/32 Tr/ 5 I/ 5
Soil 20/70 35/89 5/35 17/53 18/46 10/12 30/75 21/70 14/90
Grasses and Grasslike 20/100 30/100 40/96 53/97 30/84 4/32 42/98 9/50 36/100. 87/100 46/100 97/100
Plants
Forbs 46/100 31/96 18/95 5/68 4/50 Tr/11 8/88 1/18 13/100 5/65
Shrubs and Low Trees 8/60 3/ 9 14/36 26/52 11/22 I/ 8 7/20 19/70 4/30
^Trace (Tr) » Canopy coverage less than 0.5 percent or frequency less than 5 percent. 
2Canopy Coverage/Frequency.
-19-
West Rosebud Area
Carex syp./Fotentilla diversifolia (Carex/Podi) h.t.
This type was restricted to the alpine plateaus generally in 
excess of 9,600 feet in elevation. Herbaceous vegetation dominated, 
with sedges (Carex spp.J, and varileaved cinquefoil (Potentilla 
diversifolia) being the distinguishing species. Important grasses 
included bluegrasses (Foa spp.J, junegrass (Koeleria cristata)r and 
tufted hairgrass (Desohampsia caespitosa). Other important forbs 
included yellow avens (Geim rcssii), miIkvetch (Astragalus 
vexilliflexus), silvery lupine (Lupinus Orgenteusii moss siIene 
(Silene Ocaulisii skunk polemonium (Polemonium Visoosumii stonecrop 
(Sedum spp.J, and field chickweed (Cerastivm arvense). Marsh 
marigold (Caltha leptosepala) was extremely abundant in moist areas. 
The sparse shrub growth, which occurred only where protected from the 
severe wind, included willows (Salix spp.J, and yellow mountain heath 
(Phyllodoce glandulifIora). This type was comparable to Pallister's 
(1974) alpine tundra type, and probably included his rock outcrop- 
snowfield type.
Rock Outcrop Subtype; This type comprised the lush vegetation 
occurring at the bases of cliffs and in crevices of the large expanses 
of rock along the plateau edge. Bluegrasses dominated while sedges 
occurred in lesser amounts. Characteristic forbs included yarrow
-20-
(Achillea millefolium), yellow avens, varileaved cinquefoil and 
Parry's clover (Trifolium parryi), as well as alpine lily (Lloydia 
serotina), oblongleaved bluebell (Mertensiaoblongfolia)t and 
stonecrop. Willows and yellow mountain heath were present only in 
sheltered areas.
Abies lasiocarpa/Vaocinium globulare (Abla/Vagl) h.t. (Pfister et al.)
TIiis type occurred at elevations from 6,600 to over 9,000 feet 
over much of the West Rosebud drainage south of the Mystic Lake power 
station. Extensive fires within the last 80 to 100 years apparently 
have eliminated most climax stands below 7,500 feet elevation (U. S. 
Forest Service records). In burned areas lodgepole pine (Pinus 
contorta) was dominant forming a continuous canopy. Subalpine fir 
fAbies lasiocarpa), spruce (Picea spp.) , and Douglas fix (Pseudotsuga 
tnenziesii) also occurred in the overstory. The sparse herbaceous 
layer was dominated by timothy (Phlewn pratensis); and horsetail 
(Equisetum arvense) occurred extensively in moist areas. Forbs were 
not important. Characteristic shrubs included huckleberry (Vaeoinium 
globulare) t ninebark (Physocarpus malvaceus), Oregon grape (Berberis 
repens), and common juniper (Juniperus communis). General obser­
vations in stands above 7,500 feet indicated that subalpine fir was 
the dominant overstory species while huckleberry and ninebark 
dominated the understory. This type probably included the Douglas
-21-
fir-ninebark, Douglas fir-huckleberry, Douglas fir-snowberry and 
lodgepole pine types of Pallister (1974).
Rock Outcrop Subtype: Vegetation associated with large masses
of rock occurring within the AbZa/Vagl h.t. was classified as a 
separate subtype. Conifers, principally Subalpine fir and lodgepole 
pine, were scattered throughout, though no continuous canopy was 
formed. Major grasses and grass-like plants included bluebunch 
wheatgrass (Agropyron spieatum)y Idaho fescue (Festuoa idahoensis), 
bluegrasses, sedges, and slender wheatgrass (Agropyron eaninwn). 
Pussytoes (Antennaria spp.), goldenrod (Solidago rrissouriensis), and 
fireweed (Epilobiim angustifolium) were the most important forbs with 
lesser amounts of field chickweed, stonecrcp, and yarrow. Ninebark 
and snowbrush ceanothus (Ceanothus velutinus) were dominant shrubs 
with Oregon grape, shrubby penstemon CPenstemon fruticosus), choke- 
cherry (Primus virginiana)t common juniper, and kinnikinnick 
(Arctostaphylos uva-ursi) well represented.
Abies lasiocarpa/Vaeeinium seopariim (Abla/Vasa) h.t. (Pfister et at.)
This was a subalpine type found near Cooke City, Montana, 
generally on north exposures above 9,000 feet. Subalpine fir was 
dominant though whitebark pine (Pinus albieaulis) occasionally oc­
curred in the overstory. Sedges, bluegrasses, wire rush (Juncus 
balticiis), and mountain hairgrass (Deschampsia atropurpurea) were
- 2 2 -
important grass and grass-like plants. Principal forbs included 
arnica (Arnica Iatifolia), fleabane (Erigeron spp.J, and Virginians 
strawberry (Fragaria virginiana). Yellow mountain heath and low red 
huckleberry (Vaccinivm scoparium) were the only important shrubs. A 
rock outcrop subtype of this type was generally recognized though no 
representative sites were sampled.
Finns albicaulis/Achillea millefolium (Fial/Acmi) h.t.
This type was also found only in the vicinity of Cooke City, 
where it generally occurred on ridgetops at elevations above 9,500 
feet. Whitebark pine was the dominant overstory species although 
subalpine fir occasionally occurred. Sedges dominated among grass­
like species, with bluegrasses and spreading wheatgrass (Agropyron 
scribneri) occurring in lesser amounts. Yarrow, fleabane, and 
silvery lupine were the principal forbs. Shrubs did not occur on 
the one site sampled. A rock outcrop subtype of this type was 
generally recognized though no representative sites were sampled.
The spruce-fir type described by Fallister (1974) probably repre­
sented a composite of this and the Abla/Vasc h.t. described above.
Foa s??./Trifolium spp. (Poa/Trifo) h.t.
This type was limited to the lawn surrounding the Mystic Lake 
power plant which was used as a feeding area by bighorns. Bluegrasses 
and orchard grass (Dactylis glomerata) were the only grasses. Forbs
- 23 -
included big chickweed (Cevastium vulgatum), clover (Trifolium spp.J, 
common dandelion (Taraxacum officinale)t and plantain (Plantago spp.).
Pinus ponderosa/Festuca idakoensis (Pipo/Feid) h.t. (Pfister et at.)
This type, together with several subtypes, occurred extensively 
along the West Rosebud canyon. It was found on southeast exposures at 
elevations from 6,500 to more than 7,200 feet. Sites on which 
ponderosa pine (Pinus ponderosa) occurred on the grasslands and shrub- 
lands of the canyon were considered subtypes. In climax stands, 
ponderosa pine was dominant with lesser amounts of limber pine (Pinus 
ftexilus)t and lodgepole pine also occurring in a closed overstory.
The restricted understory growth included limited amounts of king 
spikefescue (Hesperochloa kingii), Idaho fescue, and bluebunch wheat- 
grass. Fringed sagewort (Artemisia frigida) was the only forb on the 
one site examined, and big sagebrush (Artemisia tridentata) was the 
only shrub.
Pinus contorta (Pico) Subtype: This subtype most commonly oc­
curred above 7,200 feet. Its upper elevational extreme was not 
determined. Its occurrence seemed to be related to burning within 
the last 100 years. An extremely dense stand of lodgepole pine with 
a continuous canopy was characteristic. The very sparse herbaceous 
layer included trace amounts of bluebunch wheatgrass, pussytoes, and 
arrowleaf balsamroot (Balsamorrhiza sagittate). Common juniper was
-24-
the only important shrub species. Low red huckleberry occurred in 
trace amounts. This subtype corresponded to Pallister's (1974) 
lodgepole pine type.
Artemisia tridentata (Artr) Subtype: This subtype was the most
extensive in the Pipo/Feid h.t. Individual trees of ponderosa pine 
and limber pine were scattered throughout. The understory was 
characterized by big sagebrush with canopy coverage of 25 to 30 per­
cent. Idaho fescue, bluebunch wheatgrass, and king spikefescue were 
important grasses. Sedges occurred in lesser amounts. Arrowleaf 
balsamroot and silvery lupine were the dominant forbs; those of lesser 
importance included fringed sagewort, Hood's phlox (Phlox hoodii), 
field chickweed, and Nuttall's violet (Viola nuttallii). The bunch- 
grass-sage type described by Pallister (1974) was similar to this 
subtype.
Artemisia tridentata/’Rock Outcrop (Artr/Rock Outcrop) Phase:
This phase was comprised of vegetation associated with rock outcrops 
in the Artr subtype, and was especially important to bighorns. Im­
portant overstory and herbaceous species were similar to the Artr 
subtype, except that silvery lupine. Hood's phlox, and field chickweed 
were not present. Big sagebrush and chokecherry were the major shrub 
species.
Artemisia tridentata I'Eurn (ArtWBurn) Phase: This phase
comprised a single stand within the Artr subtype which has burned,
-25-
probably within the last 20 years. This site was also important to 
bighorns. Only herbaceous plants occurred. Idaho fescue was the 
dominant grass, though king spikefescue, bluebunch wheatgrass, and 
sedges were also common. ArrowIeaf balsamroot, silvery lupine, Hood's 
phlox, fringed sagewort, and field chickweed were the characteristic 
forbs.
Populus trerruloides/Symphoriccu’pos albus (Potr/Syal) h.t.
Quaking aspen (Populus tremuloides) stands occurred at the base of 
most southeast facing slopes in the West Rosebud canyon north of the 
Mystic Lake power plant. Bluegrasses were most important among the few 
grasses present. Arrowleaf balsamroot was a major forb while silvery 
lupine and horse mint (Monarda fistutosa) occurred in lesser amounts. 
Characteristic shrubs included snowberry (Symphorioarpoe albus), 
chokecherry, and Oregon grape.
Stillwater Area
Festuca idahoensis/Agropyron spicatum (Feid/Agsp) h.t. (Pfister et at.)
This type occurred at elevations below 5,300 feet on the 
Stillwater winter range. Idaho fescue and bluebunch wheatgrass were 
the dominant and distinguishing species with bluegrasses locally 
abundant. Junegrass and sedges occurred in lesser amounts. Major 
forbs included golden aster (Chrysopsis villosa), fringed sagewort.
—26—
arrowleaf balsamroot, field chickweed, and Hood's phlox. A few shrubs, 
including chokecherry, skunkbush sumac (Rhus trilobata), and prickly 
rose (Rosa acicularis) were also present. The bunchgrass-forb type 
described by Pallister (1974) was comprised primarily of this type 
together with the Rhus trilobata and Agropyron spicatum subtypes of 
the Pseudotsuga menziesii/Agropyron spicatum h.t.
Grazed Festuca idahoensis/Agropyron spicatum Phase: Due to its
somewhat different vegetational characteristics (Table 5) and im­
portance to bighorns, that portion of the Feid/Agsp h.t. which 
occurred below the Forest Service fence on the Stillwater winter range 
was considered to be a phase of that type. This area was heavily 
grazed by horses, especially during the summer and fall. Major 
grasses included bluegrasses and downy chess brome (Brorrus tectorum). 
Sedges were moderately abundant. Fringed sagewort, Hood's phlox, 
field chickweed and pussytoes were common forbs. Skunkbush sumac 
and prickly rose were scattered throughout the phase.
Pseudotsuga menziesii/Agropyron spicatum (Psme/Agsp) h.t. (Pfister 
et at.)
This type, along with several subtypes, dominated the Stillwater 
winter range. The latter included all grass and shrublands on which 
Douglas fir occurred. Climax stands occurred at elevations above 
6,000 feet on southeast exposures and 5,000 feet on northern exposures 
Here Douglas fir, lodgepole pine, and limber pine occurred as the
- 27 -
characteristic overstory species in a closed canopy. Bluebunch wheat- 
grass and arrowleaf balsamroot were the most important grass and forb, 
respectively. Common juniper and currant (Ribes spp.7 were the most 
important shrubs.
Rhus trilobata (Fhtr) Subtype: This subtype, the most extensive
within the Psme/Agsp h.t., generally occurred between 5,200 and 5,500 
feet elevation on southeast exposures. Douglas fir trees were 
scattered throughout. Dominant grasses included bluebunch wheatgrass 
and Idaho fescue, with bluegrasses dominating moist swales. Fringed 
sagewort and cudweed sagewort (Artemisia tudoviciana) were the only 
important forbs. Skunkbush sumac was the dominant shrub with big 
sagebrush and chokecherry being locally important. Prickly rose 
occurred in limited amounts throughout the subtype.
Artemisia tridentata (Artv) Subtype: Small stands of this sub-
type occurred at elevations between 5,000 and 6,000 feet. Bluebunch 
wheatgrass was the dominant grass with downy chess broiue and sedges 
occurring throughout. Characteristic forbs included cudweed sagewort, 
field chickweed and plains prickly pear (Cpuntia pohjcantha). Big 
sagebrush was the dominant shrub with chokecherry and skunkbush sumac 
commonly present. The bunchgrass-sage type of Pallister (1974) was 
comparable to this subtype.
—28—
Agropyron epioatum (Aosp) Subtype: This subtype consisted of two
small stands on which bluebunch wheatgrass was the dominant plant 
species and shrubs were rare. Sedges, prairie sand reedgrass 
(Calamovilfa longifolia), junegrass, and needle-and-thread (Stipa 
comata) were also important. Major forbs included fringed sagewort 
and golden aster as well as field chickweed. Chokecherry and big 
sagebrush were rare shrubs.
Rock Outcrop Subtype: This type was characterized by expansive
rock outcroppings on which vegetation was sparse. Bluebunch wheatgrass 
was the only important grass. Few forbs occurred, of which cudweed 
sagewort was the most important. Dominant shrubs included big sage­
brush and skunkbush sumac, though chokecherry, squaw currant (Ribes 
cereum), common and creeping juniper (Juniperus horizontalis), and 
red dogwood (Comus stolonifera) also occurred. Pallister's (1974) 
rock outcrop-forest type was comparable to this subtype.
Pseudotsuga menziesii/Festuca idahoensis (Psme/Feid) h.t.
(Pfister et at.)
Toward the southern end of the Stillwater winter range bluebunch 
wheatgrass became less abundant while Idaho fescue increased in im­
portance, such that these two grasses co-dominated the understory 
beneath an open canopy of Douglas fir. Sedges and junegrass were of 
some importance in these stands. Common forbs included fringed sage­
wort, golden aster. Hood's phlox, and field sagewort (Arterrvtsia
-29-
ocavpestris). Shrubs were rare.
Populus tremuloides/Sympiioricarpcs albus (Potr/Syal) h.t.
Quaking aspen stands occurred on moist sites below 7,500 feet 
throughout the Stillwater winter range. These stands differed from 
those in the West Rosebud area in that grasses were more abundant and 
forbs were less common. The herb layer of the one site sampled was 
comprised mainly of bluegrasses, with a coverage of 87 percent, and 
trace amounts of timothy. Qiaracteristic shrubs included chokecherry, 
prickly rose and common snowberry. The aspen type of Pallister (1974) 
was comparable to this type;
Populus trichooarpa/Salix spp. (Potr/Salix) h.t.
Black cottonwood (Populus trichooarpa) was the dominant overstory 
species, and formed a relatively open canopy where it occurred along 
the Stillwater River bottom. Stands were subjected to heavy grazing by 
horses and a few cattle, probably causing considerable change in 
species composition from what night be expected with undisturbed con­
ditions. Grasses and grass-like plants dominated the understory, with 
ticklegrass (Agrostis scabra) and sedges the dominant species. Other 
major grasses and grass-like plants included horsetail, wire rush, 
timothy and bluegrasses. Clover was the major forb. Willow was the 
dominant shrub. This type was similar to the streamside-hardwood type 
described by Pallister (1974).
-30-
Typha latifolia (Tula) Subtype: River bottom sites with shallow
depths of standing water supported a lush growth of common cattail 
■(Typha latifolia). Horsetail was occasionally found and bluegrasses 
were common near the waters edge, though neither species occurred on 
the site sampled.
Historical Bighorn Sheep Populations and Trends
Early history of the bighorn herds of the Beartooth Mountains was 
described by Pallister (1974), who stated that bighorn numbers on the 
West Rosebud winter range apparently had remained stable at about 
forty animals from 1928 to 1970. This estimate supported previous 
estimates by Couey (1950) and personnel of the Mystic Lake power 
station near the head of the West Rosebud drainage (P. Huck pers. 
comm.).
Pallister (1974) also reported that peak numbers for the 
Stillwater winter range were reached in the late 1940 s and early 
1950's when reports of over 100 sheep on the area were common. 
Re-examination of the basis for these reports indicated that such a 
high population might be questioned.
Reports of 135 to 150 sheep during the 1944-46 period were based 
on Forest Service estimates for the Stillwater "district", not on 
actual counts. During that period, the Stillwater "district" included 
both the Stillwater and Boulder River drainages so population estimates 
did not refer exclusively to bighorns wintering in the Stillwater
-31-
valley. A 1954 Forest Service estimate of 90 bighorns applied only to 
the Stillwater winter range, but apparently was based on the single 
observation in November, 1953, of "approximately" 80 bighorns on the 
Beartooth Dude Ranch. This observation was made by ranch owner 
Edward Ickerman and reported in Buechner (1960) together with another 
observation of 36 bighorns, classified as to age and sex, by Mr. 
Ickerman in January, 1954. It seems likely that residents of the area 
extrapolated the Forest Service estimate to a population of over 100 
sheep.
The reported drastic decline of sheep in the Stillwater during the 
mid-to-late 1950's was apparently based on the Forest Service estimate 
of 90+ bighorns and actual counts by Fish and Game personnel of 55 and 
36 sheep in 1956 and 1957, respectively. As described above, the 
estimate of 90 sheep in 1954 seems questionable at best. A count by 
Fish and Game personnel in 1952 (Appendix Table 33) showed only 39 
bighorns while a population estimate in 1953 showed "about" 70 sheep. 
Two counts in 1954 tallied only 32 and 55 bighorns. These figures are 
not significantly different from Fish and Game counts made from 1956 
through 1958 which ranged from 27 to 55 bighorns. Although it is 
unlikely that all sheep using the Stillwater winter range were seen 
during these counts, it is equally unlikely that large numbers of 
bighorns escaped observation or that greatly different proportions of 
the population were observed before and after 1955.
-32-
Observations by two longtime residents of the upper Stillwater, 
Henry Bedford and Dewey Whited, supported the lower counts. Mr. Whited 
arrived in the Stillwater valley in January, 1908, and has observed the 
bighorns each year since that time, while Mr. Bedford has watched the 
sheep since arriving in the area during the early 1930's. Both gentle­
men worked on game counts in the Beartooth Mountains for the U. S.
Forest Service in the late 1930's and are considered highly reliable 
observers. Mr. Bedford reports having seen no more than 35 to 40 big­
horns on any one day while Mr. Whited places his maximum count at 40 
to 45 animals. Both men maintain that estimates of 90 or more bighorns 
on the Stillwater winter range during the late 1940's and early 1950's 
are excessive.
On these bases, I can only conclude that numbers of bighorns 
wintering in the Stillwater valley have remained relatively stable in 
recent times. Normal populations probably consisted of from 25 to 50 
bighorns with a maximum of 55 to 65 animals. Also, it seems apparent 
a drastic decline of bighorns in the Stillwater probably did not occur 
but was hypothesized to reconcile the differences between the popula­
tion estimates prior to 1954 and the actual counts of 1956.
Hunting Seasons
Prior to 1915, seasons and limits for sheep in the Beartooths were 
the same as for the rest of the state (Mussehl and Howell 1971). The
hunting of bighorn sheep was closed from 1915 to 1953 when permits were 
issued to harvest five 3/4-curl rams in the Stillwater - West Rosebud 
area. The number of permits was increased to eight for the 1954 and 
1955 hunting seasons. Because of the extreme ruggedness of the terrain 
and low hunter success, an unlimited number of permits were allowed for 
3/4-curl or larger rams in 1956. This policy remains in effect at the 
present time; although in 1975 the total harvest will be limited to 14 
sheep. Appendix Table 34 summarizes the history of hunting regulations 
and hunter harvest for the Beartooth Mountains.
Land Use
From the early 1900's until 1944 many of the alpine plateaus in 
the Beartooth Mountains were grazed by large numbers of domestic sheep 
under allotments granted by the U. S. Forest Service. As many as 600 
domestic sheep grazed Lake Plateau until 1954. Appendix Table 35 
summarizes the history of the various grazing allotments on what is 
considered to be important bighorn range.
Portions of the West Rosebud bighorn winter range were included 
in two allotments: the Mount Wood allotment, active from 1930 to
1944, and the West Rosebud Canyon and Plateau allotment, active from 
1911 to 1946. The relative amounts of grazing on each portion of the 
West Rosebud allotment is not known except for the 1921-1925 period 
when equal numbers were allowed in the canyon and on the plateau. The 
Canyon portion of the West Rosebud allotment was converted from
-33-
-34-
domestic sheep to cattle in 1947. The cattle do not presently use the 
adjacent slopes which are important as bighorn spring range. This may 
be due to the abundance of forage in the valley bottom and the short 
grazing period (approximately one month). Whether or not cattle 
grazed the slopes in the late 1940's and early 1950's is unknown.
Three grazing allotments occurred within the area believed to be 
summer range for the Stillwater population. These included the Lake 
Plateau allotment active from 1922 to 1954, the West Stillwater Plateau 
allotment active from 1922 to 1944, and the Verdigris Creek allotment 
active from 1922 to 1942. The Verdigris Creek allotment was for cattle 
and horses rather than domestic sheep. The West Stillwater Plateau 
allotment and the Verdigris Creek allotment were probably less important 
to bighorns than the Lake Plateau allotment because of limited use of 
these areas by bighorns.
The Stillwater winter range has had a long history of severe 
overuse by domestic livestock, mainly horses. In 1967 the U. S. Forest 
Service, in cooperation with owners of the Beartooth Ranch, built a 
fence across the winter range to restrict livestock to the lower por­
tions of the range and leave the adjacent slopes ungrazed for use by 
game species. Trespass livestock still occasionally graze these 
restricted areas.
The Stillwater winter range lies in a highly mineralized stip of 
land known as the "Stillwater complex". This area has been subjected
-35-
to intensive mineral searches and considerable mining activity. The 
Mouat Mine, the largest mine in the area, is located on historical 
bighorn winter range. Present use of the mine lands by bighorns is 
restricted to peripheral roads which have been reseeded with desirable 
grass species (Ballister 1974). A comprehensive report on the effects 
of mining operations on wildlife populations is presently being pre­
pared by Montana Fish and Game personnel (R. Stoneberg pers. comm.).
RESULTS
Population Trends and Dynamics
West Rosebud Area •
Population Trends. —  A maximum of 38 different bighorn sheep was 
counted on the West Rosebud winter range during winter and spring, 1975 
(Table 6). Previous spring population estimates on the area were 58 
and 59 bighorns during 1972 and 1973, respectively (Stoneberg 1973), 
and 48 in 1974 (J. Denton pers. comm.). These data suggested a 
substantial decline in numbers from 1973 to the spring of 1975.
Although it is possible that not all bighorns on the area during 
the spring of 1974 were seen (J. Denton pers. comm.), it is unlikely 
that large numbers of sheep were missed during both aerial and inten­
sive daily ground observations in the spring of 1975. Also, it seems 
unlikely that large numbers of bighorns left the area to winter else­
where during 1974 and/or 1975. Geist (1971) reported a strong fidelity 
of bighorn sheep to traditional seasonal home ranges.
Lamb Production and Survival. —  Sex and age composition of big­
horns observed in the West Rosebud drainage from June 1974 through July 
1975 are summarized in Table 6. Observed lambrewe ratios changed little 
during summer and early fall, ranging from 64 IambsrlOO ewes in July 
to 61r100 in October. Thereafter this ratio declined progressively
: I
Table 6. Sex and age composition of the West Rosebud bighorn sheep population, as determined 
from 1,355 multiple observations and monthly maximum unduplicated observations.
_____ ______ Males ____Females Number Per 100 Ewes
Sample 0-1/41 1/4-1/2 1/2-3/4 3/4+ Total
Size Curl Curl Curl Curl Males Adult Yrlg. Lambs Rams Yrlgs Lambs
1974
June 85/271 2 10/2 2/1 5/3 5/2 22/8 54/16 8/2 I/ I 41/50 15/12 2/ 6
July 135/58 1/1 8/4 3/3 12/8 75/30 48/20 16/27 3/ 73 64/67
Aug. 42/25 4/3 1/1 5/4 22/12 15/ 9 23/33 68/75
Sept. 77/26 3/2 5/3 2/1 10/6 41/12 26/ 8 24/50 63/67
Oct. 45/30 28/20 17/10 61/50
Nov. 98/45 6/2 2/2 3/2 11/6 58/25 29/14 19/24 50/56
1975
Jan. 23/14 2/2 1/1 3/3 15/ 8 5/ 3 20/38 33/38
Feb. 29/24 1/1 3/2 2/2 6/5 18/16 5/ 3 33/31 11/123 28/19
Mar. 37/28 2/2 1/1 3/3 29/20 5/ 5 10/15 14/203 17/25
Apr. 109/27 14/2 1/1 6/2 21/5 74/17 14/ 5 28/29 19/29
May 306/32 6/1 17/2 5/1 28/4 240/25 38/ 3 12/16 5/ 83 16/12
June 356/384 12/1 22/2 3/1 0/1 37/5 293/29 22/3 4/1 13/17 8/10 1/3
July 13/ 9 1/1 1/1 4/ 3 4/2 4/ 3 25/33 100/67 100/100
1Yearling males
2Total number of animals observed during month/Maximum unduplicated count during month
3Assuming a 50/50 ratio of yearling males to yearling females 
"+Maximum June observation is 1975 population estimate
from 50:100 in November to approximately 30:100 in January and February, 
1975, and to 8:100 in June. Assuming no mortality among adult ewes, 
the change in lamb:ewe ratios indicated lamb mortality of about 85 per­
cent from the summer of 1974 through the spring of 1975. On the basis 
of the July lamb:ewe ratio and the 43 ewes (including yearling ewes) 
observed on the spring range in 1974 (J. Denton pers. comm.) 28 lambs 
should have been produced. Only three lambs were observed on the 
spring range in 1975, a difference of 89 percent.
The same pattern of lamb mortality apparently occurred on the West 
Rosebud area from the summer of 1973, when Pallister (1974) observed 
64 lambs:100 ewes, to the spring of 1974 when my observations showed 
only 15 year lings: 1.00 ewes; a decrease of 77 percent. The 40 ewes 
(including yearling ewes) present on the spring range in 1973 
(Stoneberg 1973) should have produced 26 lambs. However, only two 
yearlings, one male and one female, were present the following June, 
suggesting a possible loss of 92 percent of the previous summer's 
lambs. The presence of only one male and one female two-year-old on 
the area in the spring of 1975 further supported the accuracy of the 
1974 spring count.
In contrast, Stoneberg (1973) reported lamb:ewe ratios of 41:100 
and 36:100 on the West Rosebud during the springs of 1972 and 1973, 
respectively, indicating much lower winter-spring mortality of lambs 
in those years. These data might also indicate that the recent trend
-38-
-39-
in total numbers of bighorns on the West Rosebud winter-spring range 
was directly related to iamb mortality. Relatively high and stable 
populations were experienced during 1972 and 1973, years when relatively 
high numbers of lambs survived the winter. Decreases in total numbers 
of bighorns on the area during 1974 and 1975 were associated with 
extremely high (75-90 percent) lamb mortality.
The lamb:ewe ratios of about 64:100 observed on the summer range 
during 1973 (Pallister 1974) and 1974 were relatively high for bighorn 
sheep. Frisina (1974) reported 63 lambs:100 ewes in a rapidly increas­
ing sheep population on the Sun River area of Montana. However, the 
ratio was not as high as those reported by Wishart (1958) and Horejsi 
(1972) who found 83 and 75 lambs:100 ewes, respectively, on the high 
quality Sheep River population in Alberta, and Woodard et al. (1974) 
who reported 72 lambs:100 ewes among bighorns in southern Colorado.
The occurrence of similarly high lamb:ewe ratios in 1973 and 1974 
indicated that the factor affecting lamb survival apparently did not 
affect the number of lambs produced on the area.
Sex Composition. —  Twenty nine ewes were counted on the West 
Rosebud range in the spring of 1975 (Table 6). Stoneberg (1973) 
reported counts of 33 and 36 ewes on the area during 1972 and 1973, 
respectively; while Denton (pers. comm.) counted 42 in the spring of 
1974. Apparently, lamb recruitments in 1971-72 and 1972-73 was suffi­
cient to provide at least some increase in ewe numbers during 1973 and
-AO-
1974, respectively. High lamb mortality during 1973-74 was followed 
by a decline in ewe numbers in 1975. However, some additional mortality 
of yearling or older ewes also must have occurred during 1974-75 to 
account for the 33 percent decline.
Only six rams were observed on the West Rosebud during the spring 
of 1975, two of which were larger than three-quarter curl (Table 6).
One of the large rams was illegally killed that spring leaving only one 
"legal" ram in the population. Younger rams included one coming-two- 
year-old, two three-year olds, and one four-year-old. Stoneberg (1973) 
reported ten rams, including three with 3/4-curl or larger horns on the 
area in 1972 and 14, of which nine were 3/4-curl or larger, in 1973. 
Denton (pers. comm.) counted ten rams in 1974. Three of these were 
3/4-curls.
Because rams occupy somewhat different areas than ewes on the West 
Rosebud during spring, it is possible that some rams were missed during 
spring counts. Known hunting losses accounted for only half of the 
decline in ram numbers from 1973 to 1974. Also, seven legal rams were 
killed on the West Rosebud area during the fall of 1974; four more than 
were counted the previous spring. However, rams from Yellowstone Park, 
which lies immediately south of the West Rosebud (Fig. I), probably 
range into the area during the rut and may be included in the harvest.
In contrast to Pallister's (1974) description of a ram segment 
dominated by older adult males, data for 1974 and 1975 from the West
— 4 1 -
Rosebud indicated a progressively younger age structure and a population 
similar to that found in the Stillwater River area. The difference may 
reflect increased hunting pressure and/or increased hunter success dur­
ing these two years though few data are available. The decline in 
numbers of young rams on the West Rosebud from 1974 to 1975 probably 
reflected the high lamb mortality during 1973-74 and to a lesser extent 
mortality of young rams which had been recruited into the population in 
1973 and 1974.
Stillwater Area
Population Trends.—  A maximum of 46 different bighorns was 
counted on the Stillwater winter range in 1975 (Table 7). Previous 
population estimates were 33, 42, and 47 in 1972, 1973, and 1974, 
respectively, (Stoneberg 1973, 1974).
Lamb Production and Survival. —- The sex and age composition of 
bighorns observed in the Stillwater drainage during the winter and 
spring of 1975 is shown in Table 7. The calculated winter lamb:ewe 
ratio was 41:100. Ratios of approximately 60 lambs:100 ewes were record 
ed on the area each winter since 1972 (Stoneberg 1973, 1974) indicating 
extremely high recruitment. Other investigators have reported winter 
lamb:ewe ratios ranging from 25:100 to 56:100 (Horejsi 1972, Frisina 
1974, Smith 1954, Stelfox 1974, Morgan 1970).
Although comparable ratios for the summer period were not obtained 
in the area, lamb mortality through the winter of 1975 appeared to be
Table 7. Sex and age composition of the Stillwater bighorn sheep population,as determined from 
4,159 multiple observation and monthly maximum unduplicated observations.
Males________ _____ _____ Number Per 100 Ewes
Sample
Size
0-1/41 1/4-1/2 
Curl Curl
1/2-3/4
Curl
3/4+
Curl
Total
Males Females Lambs Rams Yrlgs3 Lambs
1974
Sept. 11/ 91 2 3/3 1/1 4/4 6/ 4 I/ I 67/100 17/25
Oct. 31/12 1/1 2/1 1/1 4/3 19/5 8/ 4 21/60 11/40 42/80
Nov. 135/26 7/2 9/2 1/1 3/1 20/6 86/15 29/ 5 23/40 16/27 34/33
Dec. 143/41 4/1 9/2 3/2 16/5 94/26 33/10 17/19 9/ 8 35/38
1975
Jan. 843/46'* 78/4 38/2 36/2 152/8 ’ 492/27 199/11 31/30 32/30 40/41
Feb. 771/46 70/4 40/2 32/2 142/8 467/27 162/11 30/30 30/30 35/41
Mar. 674/43 52/4 14/2 18/2 84/8 443/25 147/10 19/32 23/32 33/40
Apr. 841/41 46/3 33/2 40/2 119/7 559/25 163/ 9 21/28 16/24 29/36
May 687/40 25/2 23/2 25/2 73/6 459/25 155/ 9 16/24 11/16 34/36
June 23/23 1/1 1/1 13/13 9/ 9 8/ 8 15/15 69/69
1Yearling males
2Total number of animals observed during month/Maximum unduplicated count during month 
^Assuming a 50/50 ratio of yearling males to yearling females
^Maximum unduplicated January observation is 1975 population estimate
4 2-
—4 3-
minimal. Lamb:ewe ratios remained nearly constant throughout the winter 
and spring periods (Table 7). Known or assumed losses included only two 
lambs, one in mid-February and another in early March., and two yearling 
ewes in early March.
Lamb:ewe ratios based on multiple observations of the same individ­
uals of a population were similar to those based on maximum unduplicated 
monthly counts (Table 7).
The constancy of the lamb:ewe ratio on the Stillwater winter range 
was evidence that no differential movement of ewes and lambs occurred 
during winter and spring.
Sex Composition.—  The 27 different ewes observed on the Still­
water winter range in 1975 (Table 7) was the highest number recorded 
since studies were initiated in 1972. Similarly, the total of eight 
rams in 1975 was the largest count since 1972.
Numbers of rams of various age classes on the Stillwater winter 
range each year since 1972 are shown in Table 8. No rams over five 
years old were observed. Pallister (1974) believed the absence of 
older rams was due primarily to hunter harvest of all legal rams that 
return to the area each fall. Large rams were reported wintering in 
the Stillwater prior to and for a few years after the area was 
opened to hunting in 1953.
— 44 -
Table 8. Age classes of all rams present on the Stillwater winter 
range from 1971 to 1975. (Table modified from Stoneberg 
1974).
' • Age (Years)
0.51 1.5 2.5 3.5 4.5 5.5+
1971-72 5 I 3 0 0 0
1972-73% 7 5 2 I 0 0
1973-743 7 2 3 2 I 0
1974-75^ 5 4 2 2 2 0
1Assuming a 50/50 ratio of male: to female lambs.
2Includes one yearling and one 2)5 year old found dead.
3Includes one 4*5 year old that was taken by a hunter.
^Includes one 3*5 year old and one 4*5 year old that were taken by
hunters.
Geist (1971) reported that movements of rams are generally rigidly 
established by the age of 4^ years. Thus, all 4$5-year-old or older 
rams on the Stillwater winter range would be expected to return in 
subsequent years. At present relatively few 415-year-old rams occur
-45-
on the Stillwater (Table 8). Apparently most rams in this age class 
attain 3/4-curl horns and are taken by hunters before or upon returning 
to the winter range.
There was no significant or consistent decline in numbers of rams 
of any year class between Ih and 4$s years of age (Table 8), indicating 
few if any rams leave the area to winter elsewhere before reaching four 
years of age. Geist (1971) observed that young rams rarely leave ewe 
groups until their third summer and may or may not return to the 
maternal winter range in either or both of the following two winters 
depending upon the habits of other rams they may be associated with in 
early winter.
Comparisons between numbers of lambs on the Stillwater area one 
year and the numbers of yearlings the next year (Table 8) indicated 
that many of the rams which left the winter range as yearlings failed 
to return as expected (Geist 1971) the following winter, suggesting 
some mortality during the summer or fall. Similar mortality of rams 
between their first and second winters may be inferred from the data 
of Smith (1954) and Wishart (1958) as well as from data from Montana's 
Sun River herd (M. Frisina pers. comm.). The latter two areas, at least, 
held high quality increasing populations in which survival of lambs 
was high. Yearling mortality was not evident in the findings of Geist 
(1971), Murie (1944), or Morgan (1970) for static or declining popula­
tions with low lamb survival. This might suggest that high survival
— 46 —
of lambs through their first winter may be followed by relatively 
higher mortality of yearlings during the following summer and fall. 
Conversely, low over-winter survival of lambs may be compensated for 
by relatively high survival during the following summer and fall, 
perhaps as a result of increased mothering from ewes bearing invtable 
lambs (Geist 1971).
Seasonal Distribution and Movements
Centers of activity (Hayne 1949) and standard diameters (White 
1964), indicative of seasonal home ranges, were calculated for each of 
21 marked bighorns observed three or more times during a season. 
Standard diameters were calculated as: SD STAE2ZN, where D equals
twice the distance from the center of activity to each relocation and 
N equals the number of relocations (Harrison 1958). The standard diam­
eter is defined as a circle which contains 68.26 percent of the reloca­
tions of the marked animal (White 1964).
The seasonal distribution of bighorns within the study area, is 
shown in Figure I. Monthly and seasonal centers of activity and 
standard diameters are given in Appendix Tables 36 and 37 for the West 
Rosebud and Stillwater areas, respectively.
West Rosebud Area
Winter. —  During winter, most marked bighorns were located on 
plateaus between the Mystic Lake power plant and Mystic Lake. No sheep
-47-
were observed south or west of the upper end of the lake. Unmarked 
bighorns, believed to be part of the West Rosebud population, were seen 
on Fishtail Plateau, at the heads of the Middle Fork of Fiddler Creek 
and the East and West Forks of Fishtail Creek, as well as on Stillwater 
Plateau above Woodbine Creek and between Woodbine and Falls Creeks.
The pooled standard diameter of individual home ranges for the 
area during winter was 1.53 miles (Table 9). The average distance 
between successive relocations was 0.88 miles; and the average maximum 
distance individuals were relocated from their center of activity for 
the period was 1.18 miles. These data included migrational movement 
from the alpine plateaus to slopes along the West Rosebud Canyon in 
late winter. Movements on the plateaus or in the canyon were more 
restricted than indicated by averages for the winter. The pooled stand­
ard diameter and average distance between successive relocations was 
similar to that reported by Erickson (1972) for bighorns in the Sun 
River area of Montana, though the latter measurement was much smaller 
than that reported by Morgan (1970) for bighorns in the Salmon River 
area of Idaho.
Spring. —  During this period, bighorns on the West Rosebud were 
distributed between Pine Grove Campground and Mystic Lake along the west 
side of the Rosebud drainage and from the Mystic Lake power plant to 
the dam on the east side. Only rams were seen as far north as the 
campground. Bighorns freely crossed West Rosebud Creek only between
Table 9. Pooled standard diameters, average distances between consecutive relocations and
average maximum distances from winter range centers of activity of bighorn sheep on 
the West Rosebud and Stillwater areas during the study period.
West Rosebud Stillwater
Winter Spring
1974
Spring
1975
Summer Fall Winter Spring Fall
Pooled Standard Diameter 
in Miles
1.53 2.22 1.54 9.23 - 0.78 0.93 1.76
Range of Individual 
Standard Diameters
0.44-1.92 0.25-3.46 0.82-2.36 0.58-18.39 0.50-1.01 0.57-2.23 0.98-2
Average Distance Between 
Relocations in Miles
0.88 1.15 0.41 2.44 0.37 0.50 0.75
Number of Animals 4 5 5 7 - 11 11 3
Number of Observations 20 26 48 49 684 193 17
Average Maxiumum Distance 
from Winter Range Center 
of Activity in Miles*
1.18 1.59 1.83 6.83 8.38 1.03 1.06 1.29
Range of Maximum Distances 
in Miles
0.5 -1.6 0.3 -3.0 0.8 -3.8 0.8 -21.8 2.4 -21.8 0.5 -1.6 0.55-1.8 0.5 -3.
Number of Animals 6 8 5 8 8 11 11 5
Number of Observations 23 32 48 50 17 684 193 20
1Five of the West Rosebud bighorns were not observed a sufficient number of times to calculate winter range centers 
of activity. In these cases spring range centers of activity are used for this calculation.
89
-
-49-
the power plant and the dam. Movement across the creek was not known 
to occur below the power plant.
Data on movements of marked sheep during spring were obtained in 
both 1974 and 1975. Because movements appeared to be much more exten­
sive in 1974 than 1975, data for the two years are presented separately 
(Table 9).
The pooled standard diameter for the spring was 2.22 miles in 1974 
as compared with 1.54 miles in 1975, while the mean distance between 
consecutive relocations in 1974 and 1975 was 1.2 and 0.41 miles, 
respectively. These differences probably reflected the severe climatic 
conditions during 1975. However, the pooled standard diameters for 
both years were within the range of those reported by Frisina (1974) 
for various areas of the Sun River.
During the spring bighorns were an average maximum of about 1.5 
miles from their individual winter range centers of activity though 
some sheep had moved nearly four miles from those areas by the end of 
the season.
Summer. —  In late June, ewes were located on the lambing grounds. 
Lambing was not concentrated as described by Pitzman (1970) but rather 
occurred over an area of nearly eight square miles from the power plant 
to near the head of Mystic Lake. Exact locations of five lambing areas 
are given in Appendix Table 38.
—50—
Throughout July and August, most ewes and lambs ranged between the 
Mystic Lake power plant and the head of Mystic Lake along the north 
side of the canyon. Many of these animals regularly visited a salt 
block at the power plant surge tower. Geist (1971), Heimer (1973), and 
Brown (1974) have all described the desire of bighorn sheep for salt 
during mid-summer.
Three marked sheep migrated in July to the vicinity of Cooke City 
where they ranged from Miller to Cutoff Mountains, as was also reported 
by Pallister (1974). One of these, a two-year-old ram, returned to the 
power plant area in mid-August but was back in the Cooke City area by 
mid-September.
The large pooled standard diameter and average distance between 
successive relocations for summer (Table 9) reflected migrational 
movements from spring to summer range. Bighorns were widely scattered 
during summer. Some animals remained within one mile of their winter 
centers of activity while others migrated more than twenty miles. 
Similar patterns of summer dispersal were described by Smith (1954) 
and Morgan (1970) for bighorn sheep in Idaho. The migration route of 
over twenty miles from winter to summer range was similar to that found 
by Morgan (1970), but much longer than that reported by Couey (1950) 
or Erickson (1972).
Mature rams could not be located during the summer of 1974 and
apparently did not use the area in which they were observed by 
Pallister (1974) during 1973.
-51-
Fall. —  Marked sheep were only rarely observed during fall. 
Bighorns which spent the summer in the West Rosebud drainage apparently 
drifted away from the Mystic Lake power plant in late August to use 
several basins located north and west of Island and Silver Lakes as 
well as the Big Mountain and Little Park areas (R. Stoneberg pers. 
comm.).
Sheep summering in the Cooke City area utilized the same range 
until mid-October. By early November these animals were seen in the 
vicinity of Goose Lake (R. Stoneberg pers. comm.) and shortly thereafter 
were tracked to the Island Lake area (J. Denton pers. comm.).
Stillwater Area
Winter. —  During winter, Stillwater bighorns concentrated on the 
two square mile winter range near the Beartooth Ranch. No bighorns 
were seen north of the Mouat Mine or south of the rocky reef above the 
Woodbine Trail Head.
The pooled standard diameter of 0.78 miles for the winter period 
on the Stillwater (Table 9) was much smaller than that on the West 
Rosebud and those reported by Erickson (1972). As suggested by 
Pallister (1974) this was probably due to the small size of the 
Stillwater winter range. The average distance between consecutive 
relocations was only 0.37 miles, much less than reported by Erickson 
(1972) and Morgan (1970). Throughout the winter the average maximum 
distance from the individual winter range centers of activity was 1.03
—52—
miles; similar to that on the West Rosebud.
Spring. —  Bighorns occupied the same area in spring as they had 
throughout the winter.
The pooled standard diameter of 0.93 miles was slightly larger 
than that observed in the winter. The average distance between con­
secutive relocations increased to 0.50 miles indicating that the big­
horns may be moving farther in response to lighter snow conditions.
Range Use
Use of Habitat Types
The monthly and seasonal distributions of bighorns according to 
habitat types for the West Rosebud and Stillwater are given in Tables 
10 and 11, respectively. Because rams generally occupied the same 
habitat types as ewes and lambs, data for all sex and age classes of 
bighorns were combined.
West Rosebud Area
Winter (January-April). —  The Capex/Podi h.t. on the alpine 
plateau was the single most important type in use by bighorns through­
out the winter (Table 10). Usage of this type was greatly under­
estimated because of my inability to observe it regularly. The Arin 
subtype (Pipo/Feid h.t.) ranked second, though actual use was light 
or only occasional until April, when usage gradually increased as the 
sheep moved down from the alpine plateau. This movement coincided with
Table 10. Percent of 1,343 observations of bighorn sheep of the West Rosebud herd In various 
habitat types by month and season.
June June
Jan. Feb. Mar. Apr. Winter May 1-14 Spring 15-30 July Aug. Summer Sept. Oct. Nov. Fall
Sample Size 34 29 37 109 209 306 284 590 167 148 42 357 77 45 65 187
Carex/Podi h.t. 59 79 100 31 55 33 2 14 36 4 88 47
Rock Subtype 9 10 7 2 29 9 14 52 56 5 36
Abla/Vaso h.t. 43 5
Rock Subtype 11 4
J
Ln
W
Abla/Vagl h.t. I
Rock Subtype 29 41 35 96 27 17 58 6 2
Pial/Aomi h.t. 29 3 13 3
Rock Subtype 12 27 11
Pipo/Feid h.t. 3 2 3
Rock Subtype 4 2 3 2 I
Xrtr/Subtype 32 21 56 37 56 39 48
Artr/Burn Phase 8 12 10 2 I
Artr/KocV. Phase
Poa /Trifo h. t. 3 2
Table 11. Percent 
habitat
of 3,920 observations of bighorn sheep of the 
types by month and season.
Stillwater herd in various
January February March April Winter
Spring1
(May)
Total
<3"
Snow
>3"
Snow Total
D a
Snow
>3"
Snow Total
<3"
Snow
>3"
Snow Total
<3"
Snow
>3”
Snow Total
<3"
Snow
>3"
Snow Total
<3"
Snow
>3"
Snow
Sample Size 878 542 336 771 588 183 707 538 169 841 699 142- 3,197 2,367 830 700 604 96
Feid/Agsp h.t. 24 26 21
f -
21 25 8 . 20 26 - 34 38 14 25 29 13* 27 31
Grazed Subtype 13 10 19 \26 29 16 14 18 - 30 34 13 21 24 13* 12 14 -
Pane/Agsp h.t.
Phtr Subtype ■ 19 23 13 21 14 46 32 21 65 22 17 46 23 18 36 36 38 27
Artr Subtype 24 22 28 8 10 - , 6 8 I 5 I 25 11 10 16 6 3 21
Rock Subtype 14 11 18 13 17 19 15 33 9 10 3 14 13 15 8 8 4
Agsp Subtype 2 3 - 11 5 31 9 12 - . Tr Tr - 5 5 7 a 6 48
Psme/Feid h.t. 3 5 I - - - Tr1 2 Tr . I - - - ' I I Tr - - -
IUl
I
1Does not include 23 bighorns observed in June on unclassified habitat types, which are included in other tables.
2Trace - (Ir): less than 0.5 percent.
‘Difference in habitat use at these snow depths significant (p < .01).
sharp increases in snow depths on the plateau following late winter and 
early spring storms.
The rock outcrop subtype (Carex/Podi h.t.) provided important 
escape cover for the bighorns on the alpine plateaus. As usage of the 
Artv subtype (Pipo/Feid h.t.) increased in late winter, the Pvco subtype 
(Pipo/Fevd h.t.) provided the primary escape cover.
Spring (May I - June 15). — From May until early June the Artr 
subtype (Pipo/Feid h.t.) was used most heavily (Table 10). Use of the 
rock outcrop subtype (Abla/Vagt h.t.) gradually increased throughout 
the spring as snow disappeared. By June it was the most important type 
used by bighorns. The rock outcrops appeared to provide both increased 
security and highly palatable and nutritious green forage in the new 
growth which appeared shortly after the snow melted from these steep 
south exposures. The tendency of sheep to follow the snowline to 
higher elevations was also reported by Smith (1954).
Summer (June 15 - August 31). —  By June 15, pregnant ewes began 
to move into the most rugged areas of the rock outcrop subtypes of the 
Abla/Vagt and Carex/Podi h.t. for lambing (Table 10). These areas 
were characterized by nearly vertical rock walls broken occasionally 
by small terraces which provided the ewe with forage during her period 
of isolation. Usage of similar areas by bighorn ewes during lambing 
has been described by Couey (1950), Smith (1954), Pitzman (1970), and 
Geist (1971). Ewes and lambs were later joined by barren adult ewes
-55-
—56—
and yearlings. Most of these bighorns apparently continued to occupy 
and use the less rugged portions of these subtypes throughout the summer 
and early fall.
Some ewes and lambs, as well as yearlings of both sexes and two- 
year-old rams, migrated to the Cooke City area. This group appeared 
to use the Carex/Podi h.t. along with its rock outcrop subtype almost 
exclusively through July. Although the Carex/Podi h.t. also occurred 
in the West Rosebud drainage, areas included in this type provided very 
little escape cover as compared to areas around Cooke City where Carex/ 
Podi sites were interspersed with substantial amounts of escape terrain 
required by bighorns with young lambs. The importance of interspersion 
of rocky terrain with various habitat types in the distribution of big­
horns in the Sun River area of Montana was discussed by Erickson (1972).
Use of the Carex/Podi h.t. declined sharply during August as sheep 
in the vicinity of Cooke City moved from the alpine plateaus to use 
the subalpine Abla/Vaso and Pial/Aomi h.t.’s. This shift followed 
dessication of the alpine plants in late July and early August, and 
enabled the animal to continue to obtain succulent and highly nutri­
tious forage (Klein 1965, Hebert 1973) from the more mesic subalpine 
areas. Similar movements have been described by Picton (1960) for 
elk (CerVus canadensis), and by Mealey (1975) for grizzly bears (Ursus 
arctos).
-57-
Fall (September - November). —  In September, bighorns in the
Cooke City area resumed heavy usage of the Cavex/Podi h.t. and its rock 
outcrop subtype, though the subalpine Pial/Acmi h.t. was also used 
(Table 10). Usage of the Cavex/Podi type may have been influenced by 
a fall "green-up" or resumption of growth of some alpine plants.
The Cavex/Podi h.t. and its rock outcrop subtype continued to be 
most important in use by bighorns during October and November. Most 
bighorns observed in October were using the rock outcrop subtype. Dur­
ing late October, those bighorns which had spent the summer in the 
Cooke City area returned to the West Rosebud. By mid-November, these 
sheep as well as those which had summered in the area were using 
characteristic winter habitats. Rock outcrops were rarely used after 
this time except as escape terrain.
Stillwater Area
Winter. —  The Feid/Agsp h.t., including its grazed phase, and the 
Rhtv subtype (Psme/Agsp h.t.) were used most heavily during this period 
(Table 11). Characteristically, the bighorns bedded in the Rhtv or 
rock outcrop subtypes on the valley slopes, fed for up to an hour dur­
ing early morning in the general vicinity of the bedding area, then 
moved down to the Feid/Agsp h.t. in the valley bottom where their 
feeding usually was concentrated on the grased phase. Toward evening 
the animals gradually moved back up into the Rhtv subtype, fed for one 
to two hours, then bedded for the night.
— 58 —
During heavy snowstorms, or when three inches or more snow was 
present on the winter range, use of the Feid/Agsp h.t. declined signi­
ficantly (Table 11). Use of the Rhtr and Artr subtypes (Psme/Agsp h.t.) 
increased, though the change was not significant. During heavy storms 
the bighorns generally either restricted themselves to the Rhtr subtype 
or moved into the more sheltered rock outcrop, Artr9 and Agsp subtypes 
(Psme/Agsp h.t.) within the Stillwater canyon. Use of the canyon 
habitat types appeared to increase with severity of the weather.
The Psme/Agsp h.t. and its rock outcrop subtype were most important 
as escape cover.
The very limited Psme/Feid h.t. was seldom used, while alpine 
areas which comprised the primary winter range for the West Rosebud 
were not used. Pallister (1974) also found no use of alpine areas by 
the Stillwater herd. The alpine areas adjoining the Stillwater winter 
range were snow covered throughout the winter while little snow accumu­
lated on the valley floor. The opposite was true of the West Rosebud 
area. From this, as well as selection of habitat types, it appeared 
that bighorns selected areas and/or habitat types where desirable 
forage was available or could be obtained with minimal expenditure of 
energy. Similar observations have been reported by other investigators 
(Geist 1971, Erickson 1972).
Spring. —  Habitat usage during spring was generally similar to 
winter, though the relative importance of the grazed phase
-59-
(Feid/Agsp h.t.) appeared to decline while use of the Rhtr subtype (Psme/ 
Agsp h.t.) increased (Table 11). Increased usage of the Rhtr stands 
probably was related to the green-up of major forage grasses on the 
steeply sloping sites as well as greater availability of important forbs.
Differences in use of the various habitat types in relation to 
weather conditions were similar to those described for winter.
Distribution of Bighorns According to Physical Characteristics of 
Habitat
The average elevation of the West Rosebud winter range was over 
9,000 feet with bighorns commonly observed between 10,500 and 11,000 . 
feet (Table 12). Most of the summer range was lower than the winter 
range, varying from 6,600 to 10,500 feet. These sheep used relatively 
low elevations only in the spring, when they ranged from 6,500 to 
8,400 feet. Bighorns on the Stillwater area ranged about 5,000 feet 
lower during winter and nearly 2,000 feet lower during the spring 
(Table 13).
In the West Rosebud, bighorns were predominantly observed on 
south, southeast, and southwest exposures throughout the year 
(Table 12), though this preference became less distinct during the 
summer when all exposures were used. West exposures were relatively 
important during the winter period, although these slopes appeared to 
accumulate more snow than southerly exposed sites. Usage of northerly 
exposures increased sharply during August, probably in relation to
Table 12. Percent distribution of bighorn sheep observations according to physical character­
istics of the habitat based on multiple observations of individuals of the West 
Rosebud population.
Distance from Escaoe Cover Mean Elevation (in Feet)
<150 Yards 1504- Yards Exposure Degree Lower Upper Sample
Period Total Bedded Feeding Total Bedded Feeding S SE SW N NE NW E W  Slope Mean Extreme Extreme Size
January 100 - 100 0 _ 0 9* 32 47 - 12 - 4- — 23 9,147 7,000 10,400 34
February 100 - 100 0 - 0 7 21 41 - - - 31 12 9,728 6,900 10,600 29
March 100 - 100 0 - 0 13 41 13 3 - ■ - - 30 12 10,46,3 9,300 11,000 37
April 100 100 100 0 0 0 - 56 21 5 3 3 - 12 27 8,304 6,800 . 10,500 109
Winter 100 100 100 0 0 0 5 45 27 3 3 I - 16 22 9,022 6,800 11,000 209
May 96 100 95 4 0 5 - 84 - ‘ - 6 - 10 - 40 7,230 6,500 7,400 306
June 1-142 95 100 95 5 0 5 - 61 3 I ■ 2 4 22 6 39 6,865 6,500 8,400 284
Spring2 96 100 95 4 0 5 - 73 2 I 4 2 16 3 39 7,054 6,500 8,400 590
June 15-302 100 100 100 0 0 0 10 31 5 6 - 21 10 17 51 7,683 6.700 10,000 167
July2 100 100 100 0 0 0 30 28 17 . , 5 i 17 - 43 9,268 6,600 10,500 148
August 100 100 100 0 0 0 31 19 - - ■ 43 7 - 42 9,257 6,700 10,100 42
Summer 100 100 100 0 0 0 21 28 9 4 7 11 11 8 47 8,525 6,600 10,500 357
September 100 - 100 0 - 0 44 8 17 21 3 8 - - 25 9,944 9,000 10,400 773
October - - - - : - - 29 - 4 4 - - 22 40 42 - - 45
November - - - - ' - - 37 42 8 2 3 6 3 13 - - - 65
Fall 100 - 100 0 - 0 38 18 11 10 I 4 7 11 25 9,944 9,000 10,400 187%
^Percentage of total observations for a particular month or season that occurred on a particular exposure.
2Data from June 1974 and 1975, and July 1974 and 1975 are combined.
3Mean slope determination has a sample size of 75.
tlMean slope determination has a sample size of 185 and distance from escape cover determination has a  sample size of 77.
I
ON
?
Table 13. Percent distribution of bighorn sheep observations according to physical character­
istics of the habitat based on multiple observations of individuals of the Stillwater
population.
Distance from Escape Cover___________  Mean Elevation (In Feet)
Period
<150 Yards
Total Bedded Feeding
150+ Yards
Total Bedded Feeding S SE
Exposure 
SW N NE NW E W
Degree
Slope Mean
Lower
Extreme
Upper
Extreme
Sample
Size
January 61 100 59 39 0 41 4' 88 - 2 I - 3 i 28 5,334 5,000 6,250 878
February 52 87 49 48 13 51 17 76 - 3 - 4 - 24 5,345 5,000 7,000 771
March 70 78 70 30 22 30 19 69 “ 8 - 4 Ir* 29 5,392 5,000 7,500 707
April 43 100 37 57 0 63 12 85 2 - - - 17 5,241 5,000 6,000 841
Winter 56 90 53 44 10 47 12 80 - I 3 - 3 Tr 24 5,325 5,000 7,500 3,197
May 70 94 67 30 6 33 8 90 - 2 - - - 20 5,256 5,000 6,250 700
June 1-15 100 - 100 0 - 0 - 87 - 13 - - - 39 5,659 5,620 6,000 23
Spring 71 94 68 29 6 32 8 90 2 - - ■- 21 5,269 5,000 6,250 723
September - - - ■ - - - 10 90 - - - - 29 - - . - 10
October - - - ■ - . - - 60 ‘ * - 40 - - - - 48 - - - 15
November - - - - - 21 70 - ' - - - 9 - 37 - - 63
Fall _ _ 26 60 7 • - _ 7 38 _ - 88
^Percentage of total observations for a particular month or season that occurred on a particular exposure.
2Tr * trace: less than 0.5 percent of the total number of sheep observations occurring on an exposure during a month or season.
- 62 -
feeding in the Abta/Vaso and Fiat/Aami h.t.1s on mesic north slopes. 
Similar use of north-facing slopes by bighorns in late summer was 
reported by Smith (1954).
Over 90 percent of all sheep observations on the Stillwater winter 
and spring range were recorded on south and southeast facing slopes 
(Table 13). Warmer temperatures, together with minimal accumulations 
of snow, may account for the preference (Ballister 1974), though these . 
exposures were also preferred during the fall.
. The mean slope used by bighorns on the Stillwater range during 
winter and spring varied from 17 to 29 degrees while that used by the 
West Rosebud bighorns during the same period ranged from 12 to 40 
degrees (Tables 13 and 12). Much of the alpine winter range on the 
West Rosebud was relatively level, and slopes steeper than about 20 
degrees were rarely used until the sheep moved to lower elevations and 
slopes ranging from 30 to 60 degrees in April. The steepest slopes 
were used in late June and early July when the pregnant ewes moved to 
lambing areas. This usage of nearly 45 degree slopes continued through­
out the summer. Progressively gentler slopes were used during the fall 
as bighorns returned to their alpine winter ranges.
The importance of escape terrain to bighorns has been discussed 
by Oldemeyer et al. (1971), Erickson (1972), Frisina (1974) and 
Pallister (1974). Pallister (1974) suggested that a strong affinity 
for escape cover may lessen as bighorns move onto winter range. My
-63-
data seemed to confirm this only for the Stillwater winter range. Only 
56 percent of all bighorns observed in that area during winter were 
within 150 yards of escape terrain (Table 13). Sixty-six and 44 percent 
of all wintering bighorns observed by Erickson (1972) and Pallister 
(1974), respectively, were within 150 yards of escape terrain.
Pallister1s (1974) suggestion that use of open areas away from cover 
was related mainly to a need to secure forage was supported by the 
fact that bedding rarely occurred more than 150 yards from cover 
(Table 13). Similar observations were reported by Oldemeyer et al. 
(1971).
In contrast, sheep on the West Rosebud area appeared to be closely 
associated with escape terrain during all seasons (Table 12). However, 
the wind-blown areas most used by bighorns in winter also occurred 
largely along edges of the plateau in close proximity to escape terrain 
or cover. - •
Group Characteristics
Mean group sizes appeared to vary inversely with the security 
levels, as determined by availability of escape cover, in the areas 
used by bighorns (Tables 14, 15, and 16). Group sizes increased dra­
matically when bighorns were further than 150 yards from escape cover 
(Table 14). The difference in group size for areas over 150 yards from 
escape cover as compared to areas less than 150 yards from cover was 
highly significant (p < .005) for the period January through May.
-64-
Table 14. Relationship of mean bighorn sheep group size and distance 
from escape cover by season on the Stillwater and West 
Rosebud areas.
Season
Stillwater West Rosebud
Less than 
150 yards 
to escape
150 or more 
yards to 
escape
Less than 
150 yards 
to escape
150 or more 
yards to 
escape
Winter 7.1/2551 14.7/95 4.0/ 52 -
Spring 7.9/ 62 8.5/25 3.8/149 13.0/2
Summer - - 4.4/ 81 -
Fall - — 5.9/ 38 -
1Mean group size/Number of groups observed.
Table 15 lists mean group sizes for bighorns observed in the 
Stillwater by habitat type and/or subtype. Types are listed in order 
of increasing thresholds of security, except that the last two types 
listed were seldom used by bighorns. Groups sizes increased as the 
apparent security level of the habitat types decreased. The largest 
groups were observed on the grazed phase of the Feid/Agsp h.t. where 
a much traveled road separated the sheep from escape cover.
- 65 -
Table 15. Relationship of mean bighorn sheep group size and habitat 
type occupation on the Stillwater area during winter and 
spring, 1975.
Habitat Type or Subtype Winter Spring
Grazed Phase Feid/Agsp h.t. 20.2/331 29.0/ 3
Feid/Agsp h.t. 10.5/76 11.6/16
Psme/Agsp h.t. -
Bhtr Subtype 8.9/83 5.9/43
Artr Subtype 7.1/51 8.3/ 7
Rock Subtype 5.6/78 4.5/13
Agsp Subtype 7.9/21 9.9/ 8
Psme/Feid h.t. 4.1/ 8 -
1Mean Group Size/Number of Groups Observed.
Group sizes were relatively small on the West Rosebud area during 
all seasons and in all habitat types (Table 16). All habitat types 
used by bighorns in this area were relatively secure with escape cover 
in close proximity.
Similar relationships between group size and the cover or escape 
value of vegetation used by wild ungulates have been previously dis­
cussed for bighorns (Frisina 1974) and elk (Picton 1960).
- 66 -
Table 16. Relationship of mean bighorn sheep group size and habitat
type occupation by season on the West Rosebud area.
Habitat Type or Subtype , Winter Spring Summer Fall1
Cavex/Podi h.t. A.8/242 5.0/10 6.2/14
Rock Subtype 4.7/ 3 5.6/ 9 7.6/ 9
Abta/Vasa h.t. 18.0/ I
Rock Subtype 16.0/ I
Abla/Vagl h.t.
Rock Subtype 3.4/61 3.6/57 4.0/ I
Pial/Acmi h.t. 6.0/ 2 6.0/ I
Rock Subtype . 4.2/ 5
Pipo/Feid h.t. 3.0/ 5
Rock Subtype 2.2/ 8 1.0/ I
ArtP Subtype 3.2/24 4.6/62
Rock Phase 3.0/ I
Burn Phase 4.8/12 4.0/ I
Poa/Trifo h.t. 3.3/ 3
Overall 4.0/52 3.9/151 4.4/81 6.0/31
1Does not include 7 groups in unclassified habitat types which were
included in Table 15
2Mean Group Size/Number of Groups Observed
—67-
Food Habits
The year long food habits of bighorn sheep in the West Rosebud 
drainage were determined by examination of 36 feeding sites involving 
28,597 instances of use (Table 17), and the contents of four rumens 
(Table 18). Examination of 80 feeding sites involving 46,471 instances 
of use (Table 19) and the contents of two rumens (Table 18) indicated 
the winter and spring food habits of the bighorns in the Stillwater 
area. Preference indices, calculated as the ratio of percentage use 
on feeding sites in a habitat type to percentage canopy-coverage in 
that type (Peterson 1970), were determined for all plants with greater 
than 1.0 percent use (Tables 17 and 19). The larger the index number 
for a given food item, the greater the preference. Monthly summaries 
of bighorn food habits for the West Rosebud and Stillwater areas are 
listed in Appendix Tables 39 and 40, respectively.
West Rosebud Area
Winter (March - April). —  Three feeding sites were examined on 
the Cavex/Podi h.t. on the alpine plateau in mid-March and six on the 
Artr subtype (Pipo/Feid h.t.) during April (Table 17).
Dried forbs comprised two thirds of the plant use on the alpine 
plateau. Important species included yellow avens and moss silene. 
Sedges and sheep fescue (Festuca ovina) constituted most of the remain­
ing use.
Table 17. Mean percentages of use (U) and preference indices (P) by habitat type and/or subtype 
for each plant species used by bighorn sheep in greater than trace amounts in at 
least one type during each season in the West Rosebud area. Trace (Tr) amounts are 
less than 1.0 percent. Numbers of feeding sites examined and instances of use are 
shown in parentheses.
Taxa1______
Grasses and 
Grass-like 
Plants
ApfopyrorT^m in i^ i 
Ajropuron Beribneri 
Ajropyron epiaat.vn 
Airopyron spp. 
Aprcetie B<.’(i'rra 
Carex spp,
Daotylia
gloverata
Deeabarrpeia 
■ atropurpurea 
Deeaharpeia 
aaeepitoea 
Cset-<sa •'iahccne: L
Teet iOQ ovina 
h'eeperookloa 
kinyii
tee'.erii *r-.et.xt3
uvinea r -Dahlenberiii 
Pca spp.
Winter Spring Summer Fall
Pipe
Ccrex/ Feid/
P-'r-r, 'Feid Parer/ Abla/
PtaZ/
Jcre .r
Artr Artr/ Artr/ Vay I/ Poa/ Carex/ Podi/ Vagi/ Abla/ Carex/ Podi/
Podi Artr Rock Rock ' Trifo Fodi Rock Rock Vaea Aomi Podi Rock
(3) (6) (6) (i) (i) (3) (I) (3) (i) (3) (i) (i) (4) (2)
(2302) (6800) (6550) (1299) (1610) (2206) (650) (640) (244) (3797) (526) (460) (983) (530) .
U P U P U P U P U P V P U P V P V P U P U P U P U P V P
33.2/1.6 67.0/2.5 78.2/5.2 98.5/9.0 98.6/3.7 58.7/5.3 87.8/2.3 44.5/2.3 32.0/1.5 71.1/5.5 47.9/1.9 24.8/1.6 74.9/- 94.9/-
■ . 7.9/2.6
1.7/- 2.4/2.4 1.0/- 11.1/-
4.6/0.9 27.5/6.9 18.9/9.5 16.9/4.2 22.6/7.5 12.9/6.4
Tr/- Tr/- 
1.6/0.8
1.1/- 6.2/-
28.5/1.6 11.5/5.8 12.0/4.0 4.2/33.9 12.4/6.2
6.0/1.5
10.2/1.0 2.5/2.5 25.0/8.3 28.5/2.8 Tr/- 39.1/-
3.2/0.8
Tr/- 11.9/11.9 19.8/- 37.7/-
16.9/5.6 19.3/3.9 54.2/18.1 6.2/2.I 1.2/-
4.6/1.5 3.6/8.9 Irl- 1.6/-
14.2/2.4 17.6/5.9 21.2/3.5 81.7/16.3 1.1/-
1.8/7.2 5.3/1.8 1.3/- 
3.2/3.2
3.3/7.5 1.1/- 2.3/-
Tr/- 16.3/5.4 81.8/2.5 13.4/2.7 . 29.5/3.0 21.7/21.7 8.8/1.8 17.8/2.9 6.0/- 43.8/-
ICh
Porbs 66.8/1.7 12.7/0.9 21.7/1.6 Tr/- I.4/0.I 11.6/3.9 12.2/0.2 55.5/1.2 61.9/1.6 13.0/2.2 31.6/1.3 75.2/1.7
Tr/- 2.2/0.3
"Ti
Agoeerie gtauoa Tr/- I.7/4.5 27.4/9.1
Anerrone patene 
Antennaria spp. 
/jf92:« MiVt aKjro . 
gaert/bZtiv?
Tr/- I.3/2.8
I.3/4.3 Tr/- Tr/-
I.4/2.I
Ze^ta flaveeoene 
Amiaa latifolia 
Arterieia frijida 3.9/13.0 Tr/- Tr/-
3.6/-
15.4/2.6
Table 17. Continued.
Winter_______  _________ Spring
.Pr PvV 
Peid/' 
Artr
Pt tCpFeid .-IKV
Saves/
Podi
Artr Artv/
Rock
Artr,'
Burn
:'apz/
Rock
(3) (6) (6) (i) (i) (3)
(2302) (6800) (6550) (1299) (1610) (2206)
Taxa . U P U P U P U P U P C . P
Forbs (cont. ) 
Aster alpigenus 
Asteraaeae 
Astragalus 
■ vcH-Zl if lexus 
Salsamorrhiza 5.6/0.6 Ir/-
sagittata
Castillega ansiakii 
Conandra umbellata 6.5/37.:
Erioeron spp. Tr/-
.Fabaaeae Tr/-
Geum rossii 62.1/1.8
Meuohera Tr/-
cytindrioa 
Lloydia serotina 
Luvinus argentejs 8.7/2.2
-Merteneio a’l'-re 
Oxyria diayna 
Phlcs hjod’i 2.2/7.3 I.4/6.0
.Polygonum
bistortoides
Potentilla
diversifclia
Seneoio oan.iS
Seneoio orassulus
Silene aoaulis 3.7/1,8
Solidago
nisscuriensis 
Crifolium parry I 
Crifolium spp.
Veronica
wormskjoldii
Unknown Ir/- Tr/- Tr/-
Summer_________‘ _____ ' Fall
Pna/ varer/
izrex■ 
Pcdif
/I:*/
wzo Z/ Abla/ Pial / Cores/
Carex/
Podi/
TrijrO Fodi Rock Rock Vaso Aomi Fodi Rock
(I) (3) (i) (3) (I) (i) (4) (2)
(650) (640) (244) (3797) (526) (460) (983) (530)
U P U P V P U P U P U P V P C P
8.6/15.3 .
1.3/0.6 34.1/3.8 2.2/- %
7.2/3.6 2.2/1.I I
I.6/0.8 13.8/- i
Tr/-
32.4/39.9
Tr/-
1.6/1.6 I.2/2.4
1. 1/ 0.3
2.5/- 
1.3/1.7
Tr/-
1.1/0.I 5.7/- 
1.3/20.8
1.9/-
Tr/- 2.3/-
17.8/3.6
4.8/14.4 
4.3/6.1
4.1/9.4
11.5/0.2
26.6/4.4
2.1/2.I
Tr/- Tr/' 2.5/0.8 Tr/- Tr/ Tr/-
Table 17. Continued
Winter____________________________ Spring_________________ _____ ________________ Summer_________________________ Fal I
Cavex/
Hpo/
Feid/
Pivo/Feid 
Artv Artv/ Artr/
Abla / 
Vagi/ Foa/ Cavex/
Carex/
Podi/
Abla /
Abla/ Pial' Carex/
Carex/
Podi/
Podi Aviv Rock Rock Trnfo Fodi Rock Rock Vaso Aoni Podi Rock
(3) (6) (6) a) (I) (3) (I) (3) (I) (3) (I) (I) (4) (2)
(2302) (6800) (6550) (1299) (1610) (2206) (650) (640) (244) (3797) (526) (460) (983) (530)
Taxa U P U P U P U P U P U P U P U P U P U P U P U P U P U P
Shrubs 40.3/1.3 Ti/- Tr/- 29.7/1.4 6.1/2.0 16.0/0.5 20.5/0.8
Avo tcs taphy Ios I.4/0.7
uva-ivsz
Artenisia 39.2/1.2 Tr/- 3.1/-
tridenta ta
Fhy' I. doae 
2 larJ:<:i flora 
Phyeocarpns 5.0/0.2 4.6/1.5
I.0/0.I
raIvaoeus 
Prunue virginiana 1.1/17.6 Tr/- 18.5/- 2.9/1.0
Ribes setosMi 3.1/- Tr/-
Poea aoioularie 5.3/5.3
Salix spp. 6.1/6.1 Tr/-
Vaoainim scoparium 19.4/2.2
1Taxa not appearing in this table- because of utilization in only trace amounts but of possible local importance included: Alliwi spp., Cevastiun
arvense, Dodeoatheon pauciflovur, !,ilaceae.
-o
z-
Table 18. Mean volume percentage of each plant taxon and forage class which occurred In bighorn
sheep rumen samples collected in fall, winter, and spring since 1972 for the West
Rosebud and Stillwater areas. Trace (Tr) amounts are less than 1.0 percent. Numbers
of samples are shown in parentheses.
Taxa
West Rosebud Stillwater
Fall
(I)
November 19741
Winter
(I)
Anril 1975
Spring
(2)
Mav 1973 and 1974
Winter
(2)
1973
Poaoeae <5 Cyperaoeae 85 99 72 77
Forbs 2 Tr 3 16
Antennaria spp. I 6
Artemisia frigida 9
Artemisia ludovioiana Tr Z
Cerastium arvense Tr Tr V
Chrysopsis villosa Tr
Fabaoeae I
Heuohera cylindrica 2
Phlox hoodii I
Unknown Forbs I Tr
Shrubs 11 I 25 5
Arotostaphylos uva-ursi I
Artemisia tridentata 4 I I
Berberis repens I I
Penstemon frutioosus 14
Physoaarpus .malvaoeus 5
Pinus oontorta 3 I
Pseudotsuga menziesii Tr
Unknown Browse 7 I 2
Selaginella densa Tr Tr
Unknown 2 I
^Collection dates
Table 19. Mean percentages of use (U) and preference indices (P) by habitat type and/or subtype 
for each plant species used by bighorn sheep in greater than trace amounts in at 
least one type during winter and spring,1975, in the Stillwater area. Trace (Tr) 
amounts are less than 1.0 percent. Numbers of feeding sites examined and instances 
___________ of use are shown in parentheses. ___________________________  _____
Winter_________ _________________________ __________________ Spring
' i ' n  NV1 Psrc/ AoBP F a re ' F o tr  , 'S a lix Ee ii/A a e r Fs-e/Agsp
Grazed Ungrazed Eh tr A r t r Rock Br F e i i Climax Tvla Grazed Vngrazed Eh ir A r t r A-sp
(10) (15) (14) (8) (10) (2) (3) (I) (3) (2) (5) (4) (2) (I)
Taxa 5
(2662) (7050) (9873) (6997) (5800) (749) (1296) (802) (1483) (779) (3386) (3359) (1178) (1057)
U P U P U P U P U P U P U P V P U P U P U P U P U P
Grasses and
Grass-like Plants 0/0.3 47.5/1.2 70.0/1.1 35.1/1.2 33.5/1.4 71.7/1.7 57.9/1.5 91.6/2.0 100/1.0 92.8/- 96.2/- 82.2/- 66.0/- 51.3/-
Apropyron B p io a t r  
C a la ro / H f a lo n a ifo l ia
Tr / - 3.9/0.5 19.3/1.6 31.1/1.7 21.1/7.0 35.8/1.3 25.8/1.7 4.0/- 55.7/- 52.2/- 65.6/- 51.0/-
I.8/4.8 Tr /- I.2/0.6 I.5/8.0 Tr /- Tr /-
Tr /-'a res spp. I.1/0.2 4.8/1.6 I.5/0.9 Tr /- 3.0/12.0 6.0/2.0 10.2/1.5 81.0/5.1 1.7/- 3.2/- 6.7/-
Equiee tier arocnee 
Feetusa i  dai. oe ns i  a I.7/0.8 16.6/1.0 13.5/6.8 Tr /- I.6/1.8 4.5/0.4
1.0/-
Tr /- 6.5/- Tr /-
/ "a b a lt is :,3 Tr /- 3.0/-
Tr /-Poe le ria  c r is ta ta I.9/1.9 I.6/1.6 Tr /- Tr /- 3.3/1.6 10.7/- 8.6/- Ir /-
I spp. 4.7/0.3 15.7/1.6 28.7/1.0 3.3/- 8.4/- Tr /- Tr /- 8.0/4.0 13.5/- 76.0/- 22.0/- 21.6/-
Eprh..: 'a t i f o l i a
Tr /- 2.0/5.3 2.3/2.3 Tr /- 25.1/6.3 3.3/-
85.5/0.9
Unknown Tr /- Tr /- Tr /- Tr /- Tr /- 2.0/-
Forbs 83.7/2.7 27.1/1.5 5.6/1.1 I.3/0.3 3.5/8.0 8.0/1.0 46.9/3.6 I.4/0.3 7.2/- 3.0/- 14.2/- 2.0/- 1.2/-
ApoaerU -Iauoa 1.0/- Tr /- Tr /- Tr /-
AKteKnaria spp. 
Apoajr . - ar.dn -
11.3/1.9 3.2/4.8 Tr /- Ir /- Tr /- Tr /- Tr /-
1.6/-
Tr /- Tr /-
8ae~i f o l i r
A r t-S- Bta sanpee ir ia  
Ar-C --Is ia  f r i p i i a  
•ip "-••• ''a ia  Iu ie  ■ lo iayia
3.0/1.5 Tr /- Tr /- I.7/1.9
Tr /-19.2/2.4 10.9/5.4 3.5/1.8 Ir /- 5.7/2.8 40.4/8.1 Tr /- 2.1/-
Tr /-Tr /- Tr /- Tr /- 1.0/1.0 2.5/20.0 2.3/36.8 Tr /- Tr /-
te ’ ear.crrh is a I.2/0.6 Tr /- Tr /- 5.5/-
B a p it ta ta  
i  r  rs ti-c -  a r cey-Be Tr /- Tr /- Tr /- 4.1/- Tr /- Tr /-
E r ' e reK spp. 
E r l x  K .
Tr /- 
49.3/7.0 9.2/4.6 Tr /-
I.2/1.2 
I.2/1.6 1.8/- Tr /-
C o li l tp o 1.4/-
A pffo  t r  le w is
Shrubs 6.3/0.8 25.3/8.4 24.4/1.7 63.6/2.4 63.0/5.7 20.3/40.6 3.4/0.8 Tr /- 3.6/- 31.9/- 47.5/-
A r t c r ie ia  t r i ie n ta t a 10.4/22.0 12.3/17.7 19.2/0.9 7.6/3.8 2.9/46.4 Tr /- 7.4/r 1.2/-
Se rbe ria  r eveyf  
r in us  f ' ■ - i  I -a
Ir /- 
Tr /-
2.4/-
Fpp ila s  t r ic h e oarpa 
FruK <s v i r p iKitxna 14.5/29.0 8.3/8.3 24.1/24.1 30.6/30.6 12.4/-
1.0/-
2.5/- 1.4/- 2.5/-
Fsc-doteupa 8.8/8.8
-c* z i e s i i  
Eh;,s z r i lc b a ia 6.3/1.3 Ir /- 3.1/0.3 19.9/6.6 13.2/6.6 4.9/-
Tr /- Tr /- 4.9/- 43.8/-
S a lis  spp.
rx r f  CB a 'iu s Tr /-
2.4/0.6
18.3/-
S’i!" Tr /- Tr /- Ir /-
Tr /- 3.6/0.4
5Faxa not appearing In this table because of utilization in only trace amounts but of possible local importance Included: Aproet ie  eaabra, Bro~;<8 t e - l  "  -,
E ltfViB Sana ie ra ie t Fh le i/- prctCKB ie, Conaninx ^ r re lla U it EmpopolIon l i c i t e .
-73-
High utilization of forbs during winter, as observed on the alpine 
plateau, may be unusual for bighorn sheep. Other investigators have 
reported use of forbs ranging from four to 21 percent during winter 
(Sugden 1961, Schallenberger 1966, Constan 1972, Morgan 1970, Todd 1975). 
The difference could reflect the limited availability of forage plants 
on the alpine plateaus, especially in late winter. Pallister (1974) 
reported that forbs comprised only two percent of the plant use at one 
bighorn feeding site on the West Rosebud winter range in December,
1973. General observations in the area of feeding sites on the plateau 
indicated very little standing vegetation at the time my data were 
obtained in March, 1975. Lovaas (1958) found increasing use of forbs 
by mule deer as browse species were depleted on winter range.
When the bighorns migrated down from the alpine plateaus in late 
winter, grasses (47 percent of the total use at feeding sites) and 
shrubs (40 percent of the recorded use) became the most important 
sources of forage in the heavily used Artr subtype (Pipo/Feid h.t.). 
Grass usage consisted mainly of new green leaves of king spikefescue 
and Idaho fescue. Sedges were also important. Big sagebrush leaves 
were used extensively, especially during periods of heavy snow.
Arrowleaf balsamroot and fringed sagewort were the only important 
forbs, with the latter having a preference index of 13. Hood's phlox 
received less usage but had a preference index of 7.3.
—7 4-
The one winter rumen sample examined, from a bighorn using the 
Artr subtype, contained 99 percent grasses and grass-like plants and 
only one percent big sagebrush (Table 18).
Spring (May I - June 15). — Throughout the spring grasses and 
grass-like plants were utilized most heavily in all habitat types 
(Table 17). Bluebunch wheatgrass, sedges, Idaho fescue, and king 
spikefescue were highly preferred in nearly all types in which they 
occurred. Bluegrasses were important on the rock outcrop subtype 
(Abla/Vagl h.t.) and the Poa/Trifo h.t. Bastard toadflax (Comandva 
umbellata), silvery lupine and roundleaved allumroot (Heucheracylindrioa) 
were important forbs. Shrubs were important only on the rock outcrop 
subtype (Abla/Vagl h.t.) where leaves of chokecherry and ninebark were 
utilized.
The two rumen samples, collected from bighorns using the rock 
outcrop subtype (Abla/Vagl h.t.) during spring in 1973 and 1974 
(Table 18) indicated greater usage of grass and less use of forbs than 
feeding site examinations in 1975. This may have been due to the lack 
of forbs on the area in May, 1975, when cold weather apparently 
suppressed forb production.
Summer (June 15 - August 31). —  Forbs were the most important 
forage used during summer in three of the five habitat types sampled 
(Table 17). The most important species included false dandelion 
(Agoseris glauca), arnica, milkvetch (Astragalus vexilliflexus)t
- 7 5 -
ha Ir y Indian paintbrush (Castillega cusickii), fleabane, alpine lily, 
moss silene and Parry’s clover. Grasses, including bluebunch wheat- 
grass, tufted hairgrass, and bluegrasses ranked second for use overall 
and were most important on the rock outcrop subtype (Abta/Vagt h.t.) 
and the Abta/Vasa h.t. Bluegrasses appeared to be highly preferred in 
all types. Sedges were also preferred. Shrubs were important only on 
the rock outcrop subtype (Abta/Vagt h.t.) where prickly rose, ninebark, 
and chokecherry were utilized, and on the Abta/Vasa h.t. where low red 
huckleberry was of some importance. Prickly rose and low red huckle­
berry were especially preferred (Table 17). Pallister (1974) reported 
much higher utilization of both forbs and browse during the summer.
Fall (September-November). —  The most important forage class in 
the fall was grasses (Table 17). Tufted hairgrass, bluegrasses, 
spreading wheatgrass and sedges were the most important species. Forbs 
were utilized only on the Carex/Podi h.t. with yellow avens and silvery 
lupine being most important. Shrubs were not important in the areas 
sampled. One rumen sample (Table 18), collected in November, showed 
higher usage of shrubs than occurred at feeding sites. Pallister 
(1974) reported similar shrub usage but lower utilization of forbs 
during the fall.
Stillwater Area
Winter (December-April). —  Over the winter, utilization of 
grasses, forbs and shrubs averaged 50.0, 15.4 and 34.4 percent.
—7 6—
respectively, though use varied somewhat by habitat type and/or 
subtype (Table 19).
Grasses were most important in the Feid/Agsp h.t., RhtP and Agsp 
subtypes (Psme/Agsp h. t.), Psme/Feid h.t. and the Potr/Salix h.t. with 
its Tyla subtype. Bluebunch wheatgrass was preferred and heavily used 
on the Khtr and. Agsp subtypes and the Psme/Feid h.t., but was seldom 
used on the Feid/Agsp h.t. Sedges also were important and preferred 
in these types. Bluegrasses were very important on the RhtP subtype 
and the Feid/Agsp h.t. where swales maintained at least some green 
forage throughout the winter. The low preference index for bluegrass 
in the RhtP subtype (Table 19) reflected the abundance of bluegrass in 
these swales where canopy coverage transects were generally placed 
rather than a lack of preference. Idaho fescue was also important and 
preferred in the Rhtp subtype and the Feid/Agsp h.t., though most of 
the usage did not occur until the green-up in March. Usage of grasses 
and grass-like plants in the Potp/Sdlix h.t. was generally limited to 
sedges and bluegrasses, while green common cattail shoots were heavily 
used in the Tyla subtype.
Among these types, forbs were of major importance only on the Feid/ 
Agsp h.t. and the Psme/Feid h.t. Fringed sagewort was very important 
on both of these types and was highly preferred wherever it occurred. 
Hood's phlox was also heavily used and highly preferred on the Feid/ 
Agsp h.t. Shrub usage was high on the Feid/Agsp h.t. as well as the
-77-
Rhtr and Agsp subtypes. Big sagebrush and chokecherry were heavily 
utilized and highly preferred with lesser use on skunkbush sumac.
Forbs dominated the bighorn diet only on the grazed phase of the 
Feid/Agsp h.t. Hood's phlox, fringed sagewort and pussytoes were 
important and highly preferred, possibly because they remained somewhat 
green throughout the winter. Bluegrasses were also important, while 
skunkbush sumac was used during storms. Since bighorns selectively 
fed on this type throughout the winter, forbs probably comprised a 
greater part of their total diet than indicated by the pooled data from 
all habitat types. Several observers have reported that fringed sage- 
wort appeared to be a highly important forage species for bighorns 
(Spencer 1943, Sugden 1961, Schallenberger 1966, Constan 1972, Cooper- 
rider 1969, Todd 1975). Hood's phlox has not previously been considered 
a major forage species though it appeared to be nearly as important as 
fringed sagewort in the Stillwater.
Shrubs were the most important forage class used by bighorns on the 
Artr and rock outcrop subtypes (Psme/Agsp h.t.). Big sagebrush, 
chokecherry, and skunkbush sumac were the most important browse species 
with the latter two being highly preferred. Douglas fir was also used 
on the rock outcrop subtype. Bluebunch wheatgrass was also important 
on these sites. Forbs were relatively unimportant, with cudweed sage­
wort being used most often. On two occasions rams were observed to 
eat lichen from rock faces.
-78-
Two rumen samples, collected during the winter of 1973 showed a 
high use of grasses and grass-like plants (Table 18). Forbs ranked 
second, with fringed sagewort, pussytoes, and Hood’s phlox being the 
most important species. Browse was relatively unimportant with big 
sagebrush, Oregon grape, and lodgepole pine being utilized.
Spring (May I - June 15). —  Grasses dominated use at feeding sites 
during the spring with shrubs second in importance (Table 19). New 
leaves of bluebunch wheatgrass were selected for in nearly all types. 
Bluegrasses were heavily utilized oh the Feid/Agsp h.t. and its grazed 
subtype as well as the RhtP subtype (Psme/Agsp h.t.). Idaho fescue and 
junegrass were important on the Feid/Agsp h.t., with the latter also 
important in the grazed phase. Shrub usage was high in the Artr and 
Agsp subtypes (Psme/Agsp h.t.) where new green leaves of common snow- 
berry and squaw currant, respectively, were the most important species. 
Big sagebrush and chokecherry were also utilized.
Forbs were important only on the RhtP subtype with new shoots of 
arrowleaf balsamroot being heavily utilized.
During winter and spring, utilization of shrubs increased 
dramatically when snow depths exceeded three inches (Table 20). The
r
change occurred in all habitat types, although the bighorns tended to 
occupy sites with greater shrub availability during and immediately 
following snowstorms. Similar changes in food habits during heavy
Table 20. Relationship of snow conditions to mean percentage forage class utilization by bighorn
sheep in each habitat type and/or subtype on the Stillwater area from January to June
1975.
Grasses_______  Forbs______  ______ Shrubs_______
3 Inches 3 Inches 3 Inches
<3 Inches or more <3 Inches . or more <3 Inches or more
Habitat Type Snow Snow Snow Snow Snow Snow
Feid/Agsp h.t. 77.9 38.2 18.5 ' 19.7 3.7 42.1
Grazed Phase 36.0 3.5 64.0 74.8 - - 21.7
Psme/Agsp h.t. - - - - - ,
i
Rhtr Subtype 76.8 66.2 10.4 2.9 12.8 30.9 vI
Artr Subtype 46.4 29.8 1.8 0.8 51.8 69.4
Rock Subtype 35.9 28.7 5.1 0.3 59.0 71.0
Agsp Subtype - 59.7 - 4.0 - 36.2
Psme/Feid h.t. 53.1 — 46.9 — - -
Potr/Salix h.t. - - - - - -
Tyla Subtype 97.6 100.0 0.7 - 1.7 -
Total 63.2 46.2 16.0 9.3 20.8 44.5
-80-
snow were reported for bighorns by Schallenberger (1966), and for elk 
by Rouse (1957).
Quantity and Quality of Winter Range Forage 
Quantity of Forage Available
Standing crops of forage plants used by bighorn sheep, as measured 
at the end of the winter, on various habitat types and/or subtypes on 
the Stillwater and West Rosebud winter ranges are listed in Table 21. 
Less forage was available per unit area on the important Carex/Podi X\.t 
on the West Rosebud area than on any other type except the rock outcrop 
subtype (Psme/Agsp h.t.) in the Stillwater. Significantly less forage 
was available on the Carex/Podi h.t. than on the grazed phase of the 
Feid/Agsp h.t. on the Stillwater (p < .0001), though the difference was 
not significant when standing crops on all types were tested together 
using a Bonferroni simultaneous t-test (p = .05) (Table 22).
Total available forage could not be calculated for the Carex/Podi 
h.t. because the percentage of that type which was available to big­
horns (areas blown free of snow) was not determined. However, winter 
observations indicated that bighorns limited themselves to only a few 
small areas on which the total amount of forage, available could not 
have been large.
Significantly more forage was available to bighorns on the West 
Rosebud as they moved down to the Artr subtype (Pipo/Feid h.t.) in the
Table 21. Standing crop 
period, 1975,
of bighorn sheep 
on Stillwater and
forage species available at the 
West Rosebud habitat types.
end of the winter
Habitat Type
Standing Crop 
(lbs./acre)
Standard
Deviation
Estimated Area 
of Habitat Type 
(acres)
Total Available 
Forage (lbs.)
Stillwater
-
Feid/Agsp h.t. 1,371 941 120 164,520
Grazed Phase 598 231 80 47,840
Psme/Agep hit. — - - -
Rhtr Subtype 1,450 892 160 232,000
Artr Subtype 1,323 1,040 50 66,150 I
Rock Subtype 293 473 400 117,200
00
H
Agsp Subtype 651 417 5 3,255
Psme/Feid h.t. 1,025 456 15 15,375
Total 830 646,340
West Rosebud
Carex/Podi h.t. 301 158 - -
Pipo/Feid h.t. - - — - -
Artr Subtype 1,346 934 530 713,380
5 3 0  713,380Total
Table 22. Differences of standing crops (lbs./acre) of bighorn forage species available during 
March and April, 1975, on Stillwater and West Rosebud habitat types.
Habitat
Type
Psme/ 
Agsp / 
Rhtr
Feid/
Agsp
Pipo/ 
feid/ 
. Artr
Psme/
Agsp/
Artr
Psme/
Feid
Psme/
Agsp/
Agsp
feid/
Agsp/
Grazed
Carex/
Podi
Psme/
Agsp/
Rock
Psme/Agsp 
Rock Subtype
1.1571* 1,078* 1,053* 1,030* 732* 358 305 8 0
Carex/Podi 1,149* 1,070* 1,045* 1,022* 724* 350 297 0
Feid/Agsp
Grazed
852* 773* 748* 725* 427 53 0
jo
Psme/Agsp/
Agsp
799* 720* 695*~~ 672* 374 0
IS)I
Psme/Feid 425 346 321 . 298 0
Psme/Agsp/
Artr
127 48 23 0
Pipo/Feid / 
Artr
104 25 0 -
Feid/Agsp 79 0 ■
Psme/Agsp/
Rhtr
0
-
subtype (Psme/Agsp h.t.) is 1,157 lbs./acre
^Difference is significant (p < .05) when tested using a simultaneous t-test based on the 
Bonferroni t-table.
spring than on the alpine plateaus (Table 22). Because of the large 
area covered by this subtype, more total forage was available here 
than on the entire Stillwater winter range.
The much greater amount of forage available on the Feid/Agsp h.t. 
as compared with the grazed phase of that type (Table 21) may be indica­
tive of the effect of heavy summer and fall grazing on availability of 
forage for bighorns during the following winter and spring.
Standing crops of bighorn forage plants on the various habitat 
types of the Stillwater area were generally larger than those reported 
by Stelfox (1974) for bighorn winter ranges in Waterton, Banff, and 
Jasper National Parks. In the West Rosebud, alpine plateaus supported 
less forage than ranges evaluated by Stelfox (1974) while the Artr sub- 
type (Pipo/Feid h.t.) supported substantially more.
Quality of Available Forage Plants
Mean mid-and-late-winter percentages of protein contained in major 
bighorn forage species on the Stillwater and West Rosebud areas are 
shown in Table 23. The alpine diet listed for the West Rosebud winter 
range was a composite sample of all forage species used by bighorns 
on the alpine winter range, with each species represented in approxi­
mately the same proportion as it occurred on the area. This approach 
seemed justified because the bighorns heavily utilized all plants 
occurring on the plateau.
-83-
Table 23. Mean percentage protein content of major bighorn forage species from the Stillwater 
and West Rosebud areas.
Taxa
Stillwater West :Rosebud
Mid-February Late-April Mid-March Late-April
Agropyron spiaatum 2.2/41 18.9/4
Artemisia frigida 10.0/5 14.7/5 - 10.0/1
Artemisia tridentata 8.6/4 10.0/4 10.0/1
Balsamorrhiza sagittata - - 4.5/1
Carex spp. - — 7.1/1
Festuoa idahoensis - 13.4/3 - 6.8/1
Hesperoohloa kingii - - - . 17.6/1
Phlox hoodii 7.8/2 8.4/2 - —
Poa spp. 10.7/3 15.6/4 - - ■
Prunus virginiana 9.8/4 12.0/4 — '
Rhus trilobata 8.1/4 9.0/4 ■ -
Alpine diet - - 6.5/5 -
^Mean percent protein/Number of samples analyzed.
-85-
On the Stillwater winter range, protein levels in mid-February 
were highest for bluegrasses, fringed sagewort, and chokecherry. Both 
bluegrasses and fringed sagewort remained somewhat green throughout 
the winter, while bighorns selected only the more nutritious terminal 
buds (Bailey 1967) of chokecherry. Bluebunch wheatgrass, one of the 
most important species in the bighorn1s diet, had the lowest protein 
level of any species analyzed.
The increased protein content for all species sampled in late April 
reflected the occurrence of new green growth at that time. Bluebunch 
wheatgrass, bluegrasses, fringed sagewort and Idaho fescue were partic­
ularly nutritious.
During the winter, alpine vegetation on the West Rosebud was 
relatively low in protein as compared with most forage plants on the 
Stillwater area. Klein (1965) and Hebert (1973) found alpine vegeta­
tion to be generally much higher in protein content than vegetation 
of lower elevations. Alpine vegetation has also been reported to 
remain relatively nutritious throughout the winter (Tikhominov 1959, 
Hebert 1973). However, Nichols (1974) suggested that alpine vegetation 
which is dessicated and wind scoured probably provides relatively 
little nutrition compared to vegetation which is snow covered as was 
apparently the case in studies of Tikhominov (1959) and Hebert (1973).
The late April samples from the West Rosebud were obtained from 
lower elevational areas used by bighorns at that time. Protein values
—8  6 —
were generally higher than for the alpine sample in mid-March and 
similar to those for samples collected on the Stillwater area at the 
same time.
Measures of Population Quality
Horn growth (Wishart 1969, Geist 1971), lungworm (Protostrongylus 
spp.) larvae output (Stelfox 1974), and duration of suckling (Geist 
1971, Horejsi 1972) have all been suggested as measures of bighorn 
population quality and ultimately as measures of bighorn range quality. 
Some data regarding these factors were gathered from the West Rosebud 
and Stillwater populations incidental to other studies.
Horn Growth
Annual horn growth and circumference at annual rings for all age 
classes of rams, except lambs, was generally greater for the Stillwater 
than the West Rosebud herd (Table 24). Although sample sizes were 
small, and these differences were not significant, their consistency 
suggested superior growth among rams in the Stillwater population. 
Limited data on horn size among ewes indicated only slightly better 
growth on the Stillwater range. Ewes 3.5 years old and older from that 
area had a mean horn length of 9.54 inches and a mean basal circumfer­
ence of 5.29 inches while these measurements averaged only 9.25 and 
5.23 inches, respectively, among West Rosebud ewes. Sample sizes for 
Stillwater and West Rosebud ewes were 7 and 8, respectively.
Table 24. Mean length of annual horn growth segments and mean circumference at annual rings 
of bighorn rams from the West Rosebud and Stillwater populations.
Horn Growth
Lamb
Growth
Yrlg. 
Growth
2-Yr.-
Old
Growth
3-Yr.-
Old
Growth
4-Yr.- 
Old
Growth
5-Yr.- 
Old
Growth
6—Yr.— 
Old
Growth
7-Yr.- 
Old
Growth
8-Yr.-
Old
Growth
Length
-
- " '■
West Rosebud 3.2/61 8.6/11 6.8/11 5.8/10 3.9/10 3.6/7 3.2/6 1.9/2 1.2/1
Stillwater 2.3/5 9.3/ 5 7.7/ 3 6.3/ 2
Circumference 
at Annual Ring
' - . -
West Rosebud 3.8/5 7.3/11 10.5/11 12.6/10 13.6/10 13.5/7 14.0/6 14.4/2 14.0/1
Stillwater 3.0/5 7.6/ 5 11.0/ 3 13.7/ 2
1Mean length of horn segment or mean circumference at annual ring In Inches/Sample size.
- 8 8 -
Lungworm Larvae Output
Analysis of 47 fecal samples from the West Rosebud population and 
104 samples from the Stillwater population showed a mean output of 20.02 
(range 0 - 170.9) and 5.55 (range 0 - 125) larvae per gram, respectively. 
This difference was highly significant (p < .001). Only 4.2 percent 
of the West Rosebud samples were negative as compared with 8.7 percent 
of the Stillwater samples. The mean larval output for bighorns in the 
West Rosebud during this study was similar to that observed in previous 
years, while that for the Stillwater was lower than reported earlier 
(Stoneberg 1973, 1974). The Stillwater count was also much lower than 
had been reported by Forrester and Senger (1964). Both populations 
had lower larval output than populations studied in Canada (Uhazy et al. 
1973, Stelfox 1974). The larval output from the West Rosebud bighorns 
was similar to that found by Brown (1974) in the Thompson Falls area.
Duration of Suckling Periods
Ten suckling periods were observed in the West Rosebud area on 
July 27, 1974. The average duration was 13.2 seconds. Horejsi (1972) 
reported mean durations of 15.3 and 17.3 seconds for 11 and 107 suckling 
periods during the last two weeks of July in 1969 and 1970, respective­
ly. He associated the short suckling periods for 1969 with poor forage 
conditions while the longer suckling times occurred during a summer 
with good forage conditions.
-89-
On two occasions. West Rosebud lambs were observed suckling during 
June nearly one year after birth. Stillwater lambs were observed 
suckling no later than mid-February.
Lambing Season
Most lambs appeared to be born during the last week of June and 
early July on the West Rosebud area (Table 25), two to four weeks later 
than reported for most other bighorn ranges.
Observations of the behavior of ewe groups during June supported 
this conclusion. Pregnant ewes have been reported to isolate themselves 
from other sheep for more than a week prior to lambing (Geist 1971).
In 1975, 72 percent of the estimated adult ewe population on the West 
Rosebud was observed on June 23. Only five percent of these were 
isolated (Table 26), suggesting that a majority were one week or more 
from lambing. After June 23 the number of ewes observed dropped 
sharply as more ewes became isolated.
Previous studies of sheep throughout the United States, Canada, 
and Alaska have generally reported lambing seasons occurring between 
late April and mid-June (Sugden 1961, Biood 1963, Murie 1944, Nichols 
1974, Geist 1971, Spencer 1943, Couey 1950, Smith 1954, Morgan 1970, 
Moser 1962, Rrown 1974). Honess and Frost (1942), and Wishart (1958) 
suggested that some lambs may be born as late as early to mid-July.
The only report of a peak lambing period similar to this study was by
-90-
Table 25. Estimated birth dates of newborn 
Rosebud drainage during the early
lambs observed on the West 
summers of 1974 and 1975.
Date of 
Observation
Number of 
Lambs Observed
Estimated Birth 
Date(s)
June 29, 1974 I June 23
July 4, 1974 2 Last week of June
June 23, 1975 I June 23
June 24, 1975 I -
July 3, 1975 I July I
July 5, 1975 I June 30
Table 26. Progression of Isolation of ewes prior to lambing in 1975 
on the West Rosebud drainage.
Date
of
Observation
No. of Ewes 
Observed
Percent of Est. 
Ewe Population 
Observed
Percent of Ewes 
Observed 
In Isolation
June 3 24 86 0
June 12 28 . 100 0
June 19 14 50 0
June 23 20 72 5
June 26 16 57 6
June 29 9 32 0
Cherniavski (1962), who found that snow sheep (Ovis niwicola) in north­
eastern Siberia generally lambed during the last ten days of June.
Variation in lambing dates from area to area may be due to differ­
ences in climatic conditions, with lambs born later in areas subject 
to severe spring weather than in areas with milder conditions 
(Cherniavski 1962, Geist 1971). It seems doubtful that climatic condi­
tions in the West Rosebud area are sufficiently severe to set back lamb­
ing two to four weeks.
The lambing season of the Stillwater bighorns could not be deter­
mined. Two young lambs were seen on June 28, 1974, and were thought to 
be more than one week old at that time (R. Stoneberg pers. comm.).
-91-
- 9 2 -
Range Use and Food Habits of Other Ungulates
Mule Deer
The Avtr subtype (Pipo/Feid h.t.) appeared to receive the greatest 
use by West Rosebud mule deer during winter and spring, though the Potv/ 
Sydl h.t. was also used extensively (Table 27). Shrubs, primarily big 
sagebrush, dominated the diet during the winter period (Table 28).
Forbs ranked second, with grasses or grass-like plants only rarely used.
Table 27. Percent of 718 observations of mule deer in various habitat 
types during winter and spring 1975 in the West Rosebud area.
Season
Sample
Size Pipo/Feid/Avtv Po tv/Syal Poa/Tvifo
Winter 323 78 19 3
Spring 395 89 10 I
Use of grasses and forbs increased dramatically during the spring 
when they appeared to be of equal importance to shrubs. King spike- 
fescue comprised most of the grass used, and shooting star (Dodecatheon 
oonjugans the major forb. Big sagebrush was the only shrub observed 
to be used.
Table 28. Mean percentage of use (U) and preference Indices (P) by habitat type and/or subtype
of each plant species used by mule deer during winter and spring, 1975, in the Still­
water and West Rosebud areas. Trace (Tr) amounts are less than 0.5 percent. Numbers
of feeding sites examined and instances of use are shown in parentheses.
Taxa
Stillwater West Rosebud
Winter Spring Winter 
Pipo / 
Feid/ 
Artr 
(2)
(1161)
U P
Spring
Pipo/
Feid/
Artr
(3)
(706)
U P
Feid/Agsp
(3)
(768)
U P
Psme/Agsp
Rhtr Artr
(7) (I)
(6691) (1772)
U P U P
Psme/
Agsp/
Potr/Syal Rhtr
(I) (I)
(214) (165)
U P U P
Grasses and Grass-
like Plants 1.2/ 0.3 1.1/0.02 60.6/- 5.2/- 32.2/-
Agropyron spicatum Tr/ - 38.8/- 3.8/- 7.2/-
Carex spp. Tr/ - Tr/-
Festuoa idahoensis 0.7/ 0.04 20.6/- Tr/- 2.0/-
Hesperoohloa kingii 0.7/- 22.7/-
Junous baltious Tr/-
Poa spp. 0.5/ 0.05 0.9/0.03 1.2/-
Forbs 37.6/ 2.1 2.4/0.5 23.0/- 8.9/- 32.6/-
Agoseris glauoa Tr/-
Alli'im spp. 12.1/- 1.6/-
Anemone patens 0.7/-
Antennaria spp. 0.8/ 0.8 Tr/-
Artemisia frigida 20.4/10.2 1.3/0.6 6.7/- 6.5/- 1.8/-
Artemisia ludovioiana 1.0/ 1.0 Tr/ -
Balsamorrhiza 8.1/ 4.0 0.6/1.3 1.2/-
sagittata
Cerastium arvense 0.6/- 0.7/-
Chrysopsis villosa 4.9/ 1.2
Claytonia lanoeolota Tr/-
Delphinium bioolor 5.5/-
Dodeoatheon oonjugans 15.2/-
West Rosebud
Table 28. Continued.
Stillwater
Winter Spring Winter Spring
Psme/Agsp - ' Psme/ Pipo/ Ptpo/
Agsp/ . feid/ Feid/
Feid/Agsp Rhtr Artr Potr/Syal Rhtr . Artz1 Artr
(3) (7) (I) (I) (I) (2) (3)
(768) (6691) (1772) (214) (165) (1161) (706)
Taxa U P U P U P U P U P U P U P
Forbs (cont.) ■
• " '
Erigevon spp. 
Lilaaeae 0.6/-
Tr/-
Musineon 1.8/-
divarication 
Phlox hoodii 2.3/ 1.2 Tr/- 0.9/- 1.1/-
Unknown Tr / - 3.0/- 3.3/-
Shrubs 61.2/20.4 96.5/ 6.9 100.0/3.8 100.0/5.3 16.4/- 86.0/- 35.3/-
Artemisia 11.7/24.9 26.8/26.8 11.9/0.5 4.7/ - 75.7/- 35.3/-
tridentata 
Juniperus communis Tr / - 44.9/ - 1.6/-
Juniperus 8.9/ -
horizontalis
Pinus flexilus 
Populas tremuloides 0.9/ 7.2 Ir/ -
■ Tr/-
Prunus virginiana 3.5/ 7.0 11.6/11.6 26.7/26.7 27.1/9.0 • 7.5/-
Pseudotsuga 14.5/ - 8.5/-
menziesii 
Rhus trilohata 46.0/ - 57.0/ 5.2 61.0/20.3 7.9/-
Ribes spp. Tr / - 0.7/-
Rosa acicularis Tr/-
-95-
Mule deer on the Stillwater winter range used the Rhtr and Artr 
subtypes (Psme/Agsp h.t.) heavily throughout the winter (Table 29). 
During spring, use of the Feid/Agsp h.t. increased substantially as 
new growth of forbs became available.
Table 29. Percent of 1,656 observations of mule deer in various habitat 
types during winter and spring, 1975, in the Stillwater area.
Sample Feid/Agsp Psme/Aqsp Psme/ Potr/ Potr/
Season Size U 1 Gz Rhtr Artr Rock Agsp Feid Syal Salix
Winter 1,272 17 2 47 25 I 4 - 2 2
Spring 384 42 2 40 9 I 2 I 3
1Ungrazed.
2Grazed.
Browse, especially skunkbush sumac, comprised the major portion 
of foods used by mule deer on these types during winter (Table 28). 
Forbs, including fringed sagewort and arrowleaf balsamroot, were 
important only on the Feid/Agsp h.t. Grass use was insignificant.
The one feeding site examined during spring showed predominate 
use of grasses, especially bluebunch wheatgrass and Idaho fescue. 
Forbs used included wild onion (Allium spp.) and fringed sagewort. 
Some browsing occurred on Douglas fir and skunkbush sumac.
Bighorns and mule deer were frequently observed feeding side by 
side. Possible social interaction was observed on only six of 42
- 96 -
occasions when bighorns and mule deer were within 50 yards of each 
other; on these occasions one or more deer moved away from an area at 
the approach of bighorns. In one case, a three-year-old bighorn ram 
moved into a small feeding crater being used by an adult female mule 
deer which immediately left the area. More often, the deer appeared 
to be somewhat more alert than usual when in the presence of sheep.
Mountain Goats
Mountain goats were observed primarily in the West Rosebud; 
only five were seen west of the Stillwater River. Goats appeared to 
prefer the Carex/Podi h.t. and its rock outcrop subtype during the 
winter and summer (Table 30). Like bighorns, mountain goats moved 
down from the alpine plateaus during May and early June to use the rock 
outcrop subtype (Abla/Vagl h.t.). From these areas, they followed the 
receding snowline to the higher elevations during late spring and early 
summer.
Table 30. Percent of 216 observations of mountain goats in various
habitat types during the summer of 1974 and the winter and 
spring of 1975.
Season
Sample
Size Carex/Podi Carex/Podi/Rock Abla/Vag2/Rock
Winter 56 52 48 -
Spring 17 ■ - - 100
Summer 195 81 12 6
-97-
The three mountain goat feeding sites examined indicated substan­
tial usage of grasses and grass-like plants during spring and fall, 
while forts appeared to be the dominant forage in summer (Table 31). 
Idaho fescue, bluegrasses, and sedges were the most important grass and 
grass-like species in spring, summer, and fall, respectively. During 
the summer, fleabane and arnica were the important forbs.
Mountain goats and bighorns were seen in close proximity on six 
occasions. On four of these occasions goats were seen feeding within 
100 yards of bighorns without interaction; on another a goat fed within 
50 feet of two bighorns. On still another occasion, a bighorn, believed 
to be a pregnant ewe in search of a place to lamb, rapidly moved away 
from the area it occupied upon approach of a goat.
Domestic Livestock
Horses. —  Horses used the grazed phase of the Feid/Agsp h.t. on 
the Stillwater winter range throughout the year, while the Psme/Feid 
h.t. was grazed during summer and early fall. Occasional use was made 
of the Feid/Agsp h.t. during all seasons.
Examination of feeding sites on these types indicated that grasses 
and grass-like plants comprised more than 90 percent of the diet of 
horses during summer, winter and spring (Table 32). Idaho fescue and 
prairie sand reedgrass were the most important grasses during the 
summer. Bluebunch wheatgrass and bluegrasses were important during
-98-
Table 31. Mean percentage of use of each plant species used by mountain 
goats during summer and fall, 1974 and spring 1975. Trace 
(Tr) amounts are less than 0.5 percent. Numbers of feeding
sites examined and instances of use are shown in parentheses.
Taxa
Spring
Abla/Vagl/Rocls.
(I)
( 74)
Summer
Carex/Podi
(I)
(412)
Fall
Carex/Podi
(I)
(168)
Grasses and Grass-like 
Plants 97.3 46.6 88.7
Agropyron scribneri ■ — 7.8 -
Carex spp. 10.8 - 86.9
Festuoa idahoensis 86.5 - —
Poa spp. — - 38.8 1.8
Forbs 2.7 53.4 11.3
Arnica latifolia - 19.4 -
Brassicaoeae - . Tr —
Caltha leptosepala — 11.3
Erigeron spp. - 31.1 -
Heuohera oylindrioa 2.7 - -
Potentilla diversifolia - Tr -
Unknown Forb _ 2.4
Table 32. Mean percentage of use (U) and preference Indices (P) of each plant species used by
horses, cattle and domestic sheep in various seasons and habitat types. Trace (Tr)
amounts are less than 0.5 percent. Numbers of feeding sites examined and instances
of use are shown in parentheses.
Horses Cattle
Domestic
Sheep
Summer Winter Spring Winter Summer
Taxa
Psme/Feid
(I)
(324)
U P
Feid/Agsp
(2)
(1253)
U P
Feid/Agsp
(I)
(822)
U P
Feid/Agsp
(I)
(286)
U P
Pial/Aomi
(I)
(724)
U P '
Grasses and Grass­
like Plants
99.4/ - 90.4/2.3 100.0/ - 95.5/ 2.4 95.0/ 5.9
Agropyron spioatum 5.2/ - 63.9/8.0 36.7/ 4.6 iVO
Brorms teotorum Tr / - 8.5/ -
Calamovilfa longifolia 47.5/ - Tr / -
Carex spp. 2.8/ - 1.7/0.6 80.2/10.0
Festuoa idahoensis 31.2/ - . 2.6/0.2 Tr / - 1.7/ 0.1
Festuoa ovina Tr / -
Junous baltious 0.9/ - 3.5/ -
Koeleria oristata 4.6/ — 0.8/0.8 Tr / - 3.1/ 3.1
Luzula wahlenbergii Tr / -
Foa spp. 3.7/ - 18.9/1.9 91.0/ - 21.7/ 2.2 14.4/ 2.4
Stipa oomata 3.1/ - 2.3/6.8 28.7/84.4
Forbs 0.6/ - 9.6/0.5 3.1/ 0.2 5.0/ 0.1
Achillea millifolium Tr / -
Agoseris glauoa 1.4/ 0.5
Table 32. Continued
Domestic
Taxa
■ Horses Cattle Sheep
Summer Winter Spring Winter Summer
Psme/Feid
(I)
(324)
U P
Feid/Agsp
(2)
(1253)
U P
Feid/Agsp
(I)
(822)
U P
Feid/Agsp
(I)
(286)
U P
Pial/Acmi
(I)
(724)
U P
Forbs (cont.)
Antennaria spp. • 0.8/ 0.8
Artemisia campestris I.4/4.1
Artemisia frigida 2.1/1.0 2.4/ 1.2 H
Artemisia ludoviciana Tr / - Tr / - ?
Cerastium arvense 3.4/1.7 0.8/ 0.8
Ckrysopsis villosa 1.4/0.4 Tr / -
Evigeron spp. 0. 6/  0.1
Fragaria virginiana Tr / -
Liatrie punctata Tr / -
Lupinus argenteus
Phlox hoodii 0.6/0.3
Tr / -
Potentilla diversifolia 
Unknown 0.6/
0 . 6/  0.6
Shrubs
Prunus virginiana 
Rhus trilobata
1.4/ 0.5 
0.7/ 1.4 
0.7/ -
- 101-
the winter, while bluegrasses dominated during spring. Forbs appeared 
to be of some importance only during the winter when field chickweed 
and fringed sagewort were utilized.
Cattle. —  Cattle use on the Stillwater winter range was generally 
restricted to use of the Potr/SaZix h.t. by a few animals in winter and 
spring, though the Feid/Agsp h.t. was also used on rare occasions. One 
feeding site examination suggested a preference by cattle for grass and 
grass-like plants during winter, with bluebunch wheatgrass, needle-and- 
thread and bluegrasses being most heavily used (Table 32). Fringed 
sagewort was the only important forb. Shrubs did not appear important 
in the cattle diet, though occasional use was noted on chokecherry and 
skunkbush sumac.
Bighorn sheep appeared wary of cattle and horses on the same range 
and would invariably move aside at their approach.
Domestic Sheep. —  Domestic sheep occupied areas considered to be 
bighorn range only during the summer in the Sheepherder-Monument Peak 
area at the head of the Boulder River. They used the alpine Carex/Podi 
h.t. and the subalpine Piat/Acmi h.t. most extensively. The one feed­
ing site examined indicated predominant use of grasses and grass-like 
plants, with sedges and bluegrasses being most important and apparently 
highly preferred (Table 32).
DISCUSSION AND CONCLUSIONS
The results of this study generally supported Ballister's (1974) 
suggestion that bighorn sheep associated with the West Rosebud and 
Stillwater areas comprised distinct populations. At no time were big­
horns from these winter ranges observed in the same area. Findings 
also indicated substantial differences in winter range use and habitat 
relationships of sheep between the two areas. These differences appar­
ently were reflected in the quality (Geist 1971), dynamics, and trends 
of the respective populations in recent years.
During winter, bighorns on the West Rosebud ranged on high alpine 
plateaus until April when they migrated downward to spend spring and 
early summer on steep valley slopes along West Rosebud Creek. Sheep 
on the Stillwater wintered at low elevations along a valley bottom. 
Range usage of bighorns on alpine plateaus was highly restricted to 
small windswept areas of the Carex/Podi h.t. on which relatively little 
forage of low nutritional value was available, at least by late winter. 
Observations at that time showed high utilization of all plants, and 
significant use of dried forbs at feeding sites. The latter appeared 
unusual for bighorn sheep, contrasting with food habits of sheep on 
the Stillwater during the same period as well as with winter forage 
preferences on other ranges, and may have reflected prior heavy 
utilization of more preferred grasses and sedges on these sites. On 
the Stillwater range, bighorns fed on a variety of habitat types; and
-103-
forage plants of generally higher protein content remained relatively 
abundant in late winter. Preferred grasses comprised most of the diet 
throughout the winter, while green or partially green forbs and browse 
plants were also available and used. These data suggest that bighorn 
sheep wintering on the West Rosebud were contending with deficiencies 
in both the quantity and the quality of forage available on primary 
range sites. The same deficiencies were not apparent on the Stillwater 
winter range. Inferior horn growth and higher lungworm larvae output 
among bighorns on the West Rosebud, probably reflected the basic differ­
ences in range use and conditions on the two areas. Reduced horn growth 
(Wishart 1969, Geist 1971) and increased output of lungworm larvae 
(Stelfox 1974) have been associated with poor quality bighorn ranges 
and populations in other areas. Similarly, the high lamb mortality 
observed on the West Rosebud during the winters of 1973-74 and 1974-75, 
as well as adult mortality in the latter winter, may have been associ­
ated with the generally low quantity and quality of winter forage on 
the alpine plateaus; though numbers of sheep on the plateau and the 
time and/or degree to which these animals were restricted, by weather 
and snow conditions, to using a few small windswept areas may also have 
been important.
Recent trends in total numbers of bighorn sheep on both the West 
Rosebud and the Stillwater range during spring appeared directly 
related to the numbers of lambs produced and surviving through winter.
-104-
Factors affecting the survival of bighorns through the winter 
apparently did not affect lamb production on the West Rosebud range.
The lamb:ewe ratio observed during the summer of 1974 was high despite 
extensive mortality of lambs during the winter of 1973-74. Lamb 
production and early survival may be influenced more by fetal growth, 
as determined by the nutritional plane of ewes during the last third 
of gestation, than by forage conditions earlier, as shown for domestic 
livestock (Maynard and Loosli 1956) and white-tailed deer (Verme 1963). 
On the West Rosebud, where lambing apparently occurred about the first 
of July, the period of greatest demand for high quality forage would 
begin about May I. By that date all sheep had moved from alpine ranges 
to lower valley slopes and were utilizing an abundance of highly nutri­
tious green forage.
Assuming the relationship between use of high quality forage dur­
ing May and June and lamb production is correct, the late lambing 
period observed on the West Rosebud could represent a local adaptation 
to seasonal range use and nutritional characteristics on the area. 
However, lambs born during late June and early July have a shorter 
summer growing season than those born during "norma]" late May or early 
June lambing periods. Such lambs might be expected to enter the winter 
substantially smaller and be subject to greater over-winter mortality 
when forage deficiencies occur.
Comparisons of food and range use habits of cattle and horses.
-105-
which grazed portions of the Stillwater winter range, with habits and 
behavior of bighorns indicated existing livestock grazing probably did 
not constitute serious competition, though more extensive use of the 
area by either or both species of livestock would likely be detrimental 
to the sheep. Existing livestock usage may have had some beneficial 
effects on sheep by increasing the availability of fringed sagewort and 
Hood's phlox on portions of the Feid/Agsp h.t. Both appeared to be 
highly preferred and nutritious forage species for bighorns, which made 
heavy usage of the grazed phase of the Feid/Agsp h.t. throughout winter. 
However, both cattle and horses heavily utilized bluebunch wheatgrass, 
an important bighorn forage plant on sites used during and following 
winter storms, as well as Idaho fescue, another important grass in the 
bighorn's winter diet. These grasses were drastically reduced or elim­
inated on areas of past heavy livestock use.
Although data were limited, observations of summer grazing of 
domestic sheep on alpine ranges suggested that such grazing probably 
would be competitive with bighorns, especially on winter range areas. 
Domestic sheep preferred and heavily utilized sedges and bluegrass 
which were found to be extremely important in the diet of bighorns on 
those areas.
At present population levels, dual use of the West Rosebud and 
Stillwater ranges by bighorns and mule deer did not appear to be 
competitive. Mule deer and bighorn sheep generally used the same
— 1 0 6 -
habitat types on both the Stillwater and the West Rosebud, except that 
deer were seldom seen in the rock outcrop subtypes (Psme/Agsp, Abla/Vagl 
h.t.'s). Food habits overlapped very little. Mule deer preferred shrubs
in all habitat types during the winter with forb use important only in
. ■ X
the Feid/Agsp h.t. Bighorns generally preferred grasses and forbs
I
with shrubs being most important only in the Artr and rock outcrop sub- 
types (Psme/Agsp h.t.). Since mule deer made little use of the Feid/ 
Agsp type and forbs were plentiful throughout, little competition with 
bighorns appeared to occur there. On other types the potential for 
competition was limited to overlapping use of chokecherry, skunkbush 
sumac, and big sagebrush. Skunkbush sumac and big sagebrush were very 
abundant and total utilization was generally only moderate. However, 
current annual growth twigs of most chokecherry were heavily utilized 
by both bighorns and mule deer, such that some forage competition for 
this species may have occurred. Overlapping food habits were also 
evident during early spring when both deer and sheep utilized new green 
growth of grasses and forbs. Some forage competition could occur when 
these are in short supply. Sharp increases in the population of either 
species may result in both land use and forage use competition (Smith 
and Julander 1953) between mule deer and bighorns.
Competition between bighorn sheep and mountain goat also appeared 
to be minimal, though these species occupied much the same habitat 
types and had very similar food habits. Although this overlap
-107-
fulfills criteria for potential land and forage use competition (Smith 
and Julander 1953) between these two species, the small numbers of 
bighorns and goats involved made competition unlikely. Similar findings 
were reported by Pallister (1974).
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Nichols, L. 1974. Sheep Report. Alaska Dept, of Fish and Game Project 
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-112-
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APPENDIX
Table 33. Actual counts and population estimates of Stillwater bighorn sheep prior to 1971.
Date Rams Ewes Adults Lambs Unci. Total Comments Source
1925 57 Total for Beartooth Mountains McLean 1930
1926 70 Total for Beartooth Mountains McLean 1930
1927 75 Total for Beartooth Mountains McLean 1930
1928 85 Total for Beartooth Mountains McLean 1930
1929 60 Total for Beartooth Mountains McLean 1930
1935-36 46 Cooney 1936
1936-37 14 18 32 13 45 Cooney 1937
1944 135 Forest Service Estimate Montana Fish and Game Files
1945 150 Forest Service Estimate Montana Fish and Game Files
1946 135 Forest Service Estimate Montana Fish and Game Files
1952 " 34 5 39 Montana Fish and Game Files
11/20/53 80 80 Estimate Ikerman in Buechner 1960
1/11/54 9 17 26 10 36 Ikerman in Buechner 1960
1954 32 32 Montana Fish and Game Files
1954 (April) 49 6 55 Montana Fish and Game Files
1954 90 Forest Service Estimate Montana Fish and Game Files
2/ 6/56 5 37 42 10 3 55 Montana Fish and Game Files
3/20/56 10 27 37 7 44 Montana Fish and Game Files
11/24/56 7 16 23 8 31 Montana Fish and Game Files
4/19/57 5 21 26 2 8 36 Montana Fish and Game Files
5/23/57 23 4 27 Montana Fish and Game Files
12/17/58 13 24 37 8 45 Montana Fish and Game Files
1965-66 I 17 18 3 21 Montana Fish and Game Files
12/9/66 I 15 16 5 21 V- Montana Fish and Game Files
2/10/67 2 15 17 10 27 Montana Fish and Game Files
2/28/68 7 20 27 6 33 Montana Fish and Game Files
4/17/69 5 14 19 2 21 Montana Fish and Game Files
1/28/70 2 21 23 5 28 Montana Fish and Game Files
— 1 1 6 -
Table 34. Statistics of bighorn sheep hunting in the Beartooth 
Mountains, 1953-1974.
Harvest
Year Known
Computer
Projection Season
Number of 
Permits
Number of 
Hunters
1953 - 10/15-11/15 5 -
1954 4 10/15-11/15 8 -
1955 2 - 9/15-11/15 8 -
1956 0 10/ 1-10/ 7 Unlimited —
1957 - - 10/13-10/20 Unlimited -
1958 - - 10/ 5-10/19 Unlimited -
1959 4 - 9/20-11/ I Unlimited -
1960 13 9/18-10/30 Unlimited - '
1961 - - 9/24-11/ 5 Unlimited -
1962 6 - 9/16-11/ 4 Unlimited 49
1963 - 9/15- ? Unlimited -
1964 - - 9/13-12/20 Unlimited -
1965 5 11 9/15-12/19 Unlimited 61
1966 6 7 9/15-11/27 Unlimited 73
1967 4 4 9/15-11/19 Unlimited 64
1968 7 9 9/15-12/15 Unlimited 54
1969 2 2 9/15-12/14 Unlimited 22
1970 3 - 9/15-11/29 Unlimited -
1971 9 22 9/15-11/28 Unlimited 144*
1972 6 24 9/15-11/26 Unlimited 245*
1973 6 22 9/ 1-11/25 Unlimited 337*
1974 16 - 9/15-11/24 Unlimited 338*
*Includes hunters in Area 301 (Yellowstone-Gallatin-Madison) and 501 
(Beartooth Mountains).
Table 35. . Statistics of grazing allotments on important bighorn sheep range, 1911-1946*.
Stillwater Area ______  ' - ______________  _______  West Rosebud Area ' ' East Rosebud Area
W. Rosebud Canyon
Date" Lake Plateau2 W. Stillwater Plateau Verdigris Creek and Plateau Mount Wood E. Rosebud Plateau
Allowed Grazed Season Allowed Grazed Season Allowed Grazed Season Allowed Grazed Season Allowed Grazed Season Allowed Grazed Season
1911-1914 • 1,058 1.058 7/1-9/30 -
1914-1921 2.685 2.685 7/1-9/30
1922 2.500 2,375 7/1-9/30 1,200 1,025 7/1-9/30 30 30 6/1-9/30 2,400 7/1-9/30
1923 - 1,000 1,200 7/1-9/30 30 30 6/1-9/30 2.400 7/1-9/30
1924 2,000 1,065 7/10-9/10 1,200 1,160 7/10-9/10 30 35 6/1-9/30 1,200 7/1-9/30
1925 2,000 2,110 7/10-9/10 1,200 1,160 7/10/9/10 30 30 6/1-9/30 1,200 7/1-9/30 ■ ;■
1926 2,200 2,200 7/10-9/10 1,075 1.200 7/10-9/10 30 30 6/1-9/30 1,200 7/1-9/30
1927 2,200 1,200 7/10-9/10 1.200 1,200 7/10-9/10 30 30 6/1-9/30 1,200 - 7/1-9/30
1928 2,200 2,143 7/10-9/10 1,200 1,200 7/10-9/10 30 0 6/1-9/30 1,200 7/1-9/30
1929 2,200 2,200 7/10-9/10 1,200 0 7/10-9/10 30 30 6/1-7/30 1,500 7/1-9/30
1930 2,200 2,214 7/10-9/10 1,200 1,200 7/10-9/10 30 30 6/1-7/30 1,800 1,400 7/1-9/30 500 575 7/10-9/10 665 - 7/10-9/10
1931 2,200 2,117 7/10-9/10 1,200 1,200 7/10-9/10 30 30 6/1-7/30 1,200 1.500 7/1-9/30 500 765 7/10-9/10 665 7/10-9/10
1932 2.200 1,200 7/10-9/10 1,200 1,500 7/10-9/10 30 30 6/1-7/30 .1,200 1,500 7/1-9/30 500 700 7/10-9/10 750 7/10-9/10
1933 2,200 2.250 7/10-9/10 1,200 1,200 7/10-9/10 30 30 6/1-7/30 1,200 1.500 7/1-9/30 500 ■ 700 7/10-9/10 800 7/16-9/15
1934 2.200 2,400 7/10-9/10 1,000 646 7/10-9/10 30 30 6/1-7/30 1,200 1,200 7/1-9/30 700 610 7/10-9/10 800 - 7/16-8/31
1935 2,200 2,200 7/10-9/10 1,200 700 7/10-9/10 30 30 •6/1-7/30 1.500 1.200 6/16-9/15 700 . 700 7/10-9/10 800 7/16-8/31
1936 2,200 2.200 7/10-9/10 1,200 700 7/10-9/10 30 30 6/1-9/30 1,800 1,175 7/1-9/15 700 700 7/10-9/10 .800 7/16-8/31
1937 2,200 1.205 7/10-9/10 1,200 900 7/10-9/10 30 30 6/1-9/30 1,800 721 7/1-9/15 700 375 7/10-9/10 730 7/16-8/31
1938 2,200 - 7/10-9/10 1,200 1,000 7/10-9/10 30 30 6/1-9/30 1,800 1,050 7/1-9/15 700 375 7/24-9/1 ■ . - " ■ *■ ' -
1939 2,200 1,200 7/10-9/10 1.200 1,000 7/11-8/31 30 . 30 6/1-9/30 1,800 1,000 7/1-9/15 Allotment cancelled Allotment cancelled
1940 2,200 1,200 7/11-9/10 1,200 1,000 7/11-8/31 30 0 6/1-9/30 1,800 1,040 7/1-9/15
1941 1,200 1,170 7/11-9/10 1,000 990 7/11-8/31 30 0 6/1-9/30 1,044 1,040 7/1-9/15
1942 1.200 1,182 7/11-9/10 1,000 1,000 7/11-8/31 Al lotment cancelled 1,044 1,040 6/16-8/31
1943 1,200 0 7/11-9/10 1,000 981 7/11-8/31 1,044 1,040 6/16-8/31
1944 1,200 0 - Allotment cancelled 1,040 1,037 6/16-8/31
1945 1,200 1,077 - - 1,040 1,040 6/16-8/31
1946 1.200 1.220_____ - ____________________________________ _______________Converted to cattle _______________;______• __________________ _
lAll allotments are for domestic sheep except the Verdigris Creek allotment for cattle and horses and the W, Rosebud Canyon allotment for cattle after 1946. 
2Lake Plateau has 2 allotments from 1922 to 1935 when the allotments were combined. Table shows total numbers for both allotments.
117-
Table 36. Monthly and seasonal centers of activity, standard diameters, maximum distances from
winter range centers of activity and average distance between consecutive relocations
for marked West Rosebud bighorns.
Tag No. Sex
Month or 
Season
No. of 
Obs.
Center of 
Activity1
Std. Dia. 
in Miles
Max. Distance from 
Winter Range Center 
of Activity in Miles
Average Distance 
Between Relocations 
in Miles
S3535 F Spring 1974 6 6007-50116 2.55 3.00 0.72
Summer 1974 6 5832-49902 15.10 21.80 5.09
Fall 1974 2 - - 21.80 ' ■
Winter 1975 5 6022-50126 0.44 0.50 0.21
S3537 F Spring 1974 2 — 1.60 —
Summer 1974 5 5987-50109 0.73 1.45 0.41
Winter 1975 4 5968-50108 1.73 1.50 1.30
May 1975 5 5985-50103 0.91 1.45 0.59
June 1-14, 1975 5 5987-50102 0.73 1.50 0.49
Spring 1975 10 5987-50103 0.82 1.50 0.54
June 15-30, 1975 8 5991-50091 0.97 2.05 0.49
S3539 F Spring 1974 2 - 0.40* -
Summer 1974 11 5961-50096 1.79 2.90 0.57
Fall 1974 2 -  . - 2.50 -
Winter 1975 2 - - 1.60 -
Spring 1975 8 5996-50104 1.16 0.95 0.26
June 15-30, 1975 8 5989-50095 1.25 2.00 0.51
S3541 F Summer 1974 3 5986-50110 0.58 1.40 0.30
Fall 1974 I - - 7.00 —
Winter 1975 5 5967-50107 1.52 1.40 1.19
May 1975 8 6012-50122 1.82 3.80 0.49
June I -14, 1975 7 5993-50110 2.26 3.25 0.45
Spring 1975 15 6005-50117 2.37 3.80 0.47
June 15-30, 1975 4 5986-50101 0.49 1.40 0.27
08 F Spring 1974 I _ _ 2.00 -
Summer 1974 4 5987-50108 0.78 2.40 0.53
Fall 1974 I - —  • 6.50 -
Winter 1975 6 5958-50109 1.92 1.10 0.84
May 1975 4 5984-50102 0.95 2.10 0.55
June I -14, 1975 3 5983-50100 0.72 2.05 0.58
Spring 1975 7 5986-50102 0.90 2.10 0.57
June 15-30, 1975 9 5991-50091 0.91 2.70 0.42
81
1“
Table 36. Continued.
Tag No. Sex
Month or 
Season
No. of 
Obs.
Center of 
Activity1
Std. Dia. 
in Miles
Max. Distance from 
Winter Range Center 
of Activity in miles
Average Distance 
Between Relocations 
in Miles
11 F Spring 1974 3 5993-50101 0.40 0.30* 0.30
Summer 1974 12 5971-50103 2.27 2.15 0.73
Fall 1974 2 - - 2.40 -
09 F Spring 1974 5 5990-50105 0.25 0.25* 0.12
Summer 1974 2 - - 0.80 -
Fall 1974 I - 1.35 -
Winter 1975 .1 - ■ - 0.95 ' -
12 M Spring 1974 7 6020-50129 2.02 2.40* 0.77 I
Summer 1974 8 5873-49956 18.39 21.80 8.20 I
Fall 1974 2 . - - 21.00 - I
Spring 1975 8 6023-50125 0.90 0.80 0.21
June 15-30, 1975 7 5990-50106 3.55 4.05 0.79
S3536 M Spring 1974 5 6023-50128 3.46 2.75* 2.69
Fall 1974 2 4.50
^Coordinates based on 1000 meter grid system on U. S. Geological Survey Topographic Maps.
*For these animals this figure is calculated from the spring range center of activity because of lack of 
winter range observations.
Table 37. Monthly and seasonal centers of activity, standard diameters, maximum distances from
winter range centers of activity and average distance between consecutive relocations
for marked Stillwater bighorns.
Tag No. Sex
Month or 
Season
No. of 
Obs.
Center of 
Activity1
Std. Dla. 
In Miles
Max. Distance from 
Winter Range Center 
of Activity in Miles
Average Distance 
between Relocations 
in Miles
$4287 F . Fall 1974 6 5862-50247 0.98 0.95 0.72
January 1975 27 5868-50241 0.71 0.75 0.37
February 1975 21 5869-50243 0.83 1.10 0.43
March 1975 18 5873-50246 1.08 . 1.15 0.38
April 1975 27 5868-50242 0.42 0.40 0.26
Winter 1975 93 5869-50243 0.76 1.15 0.36
May 1975 20 5869-50242 0.90 1.00 0.41
June 1975 I - 1.80 . -
Spring 1975 21 5869-50242 1.16 1.80 0.48
$4289 F January 1975 18 5866-50238 0.76 1.00 0.42
February 1975 24 5870-50243 0.54 0.45 0.33
March 1975 19 5869-50244 0.49 0.50 0.28
April 1975 22 5869-50241 0.46 0.50 0.27
Winter 1975 83 5869-50242 0.57 1.00 0.32
May 1975 21 5868-50242 0.57 0.55 0.35
June 1975 I - - 0.35 -
Spring 1975 22 5868-50242 0.57 0.55 0.35
$3543 F Fall 1974 5 5862-50243 2.81 3.00 0.98
January 1975 21 5865-50238 1.05 1.60 0.41
February 1975 23 5869-50243 0.88 1.20 0.49
March 1975 21 5869-50244 0.61 0.80 0.36
April 1975 26 5868-50242 0.44 0.45 0.26
Winter 1975 91 5868-50242 0.77 1.60 0.38
May/SprIng 1975 23 5868-50243 0.76 0.95 0.35
166 F Fall 1974 I _ - 0.75 -
January 1975 18 5867-50239 0.83 1.10 0.39
February 1975 18 5872-50244 1.04 1.10 0.45
March 1975 19 5872-50246 1.12 1.15 0.29
April 1975 23 5870-50243 0.98 0.95 0.42
Winter 1975 78 5870-50243 0.99 1.15 0.39
May 1975 16 5870-50243 0.89 0.90 0.48
June 1975 I - 0.40 -
Spring 1975 17 5870-50243 0.88 0.90 0.46
-120
-
Table 37. Continued
Tag No 
162
167
169
41
Sex
F
F
F
M-
Lamb
Month or No. of
Season Obs.
Fall 1974 6
January 1975 19
February 1975 14
March 1975 13
April 1975 15
Winter 1975 61
May 1975 12
June 1975 I
Spring 1975 13
January 1975 25
February 1975 15
March 1975 18
April 1975 25
Winter 1975 83
May 1975 18
June 1975 I
Spring 1975 19
January 1975 27
February 1975 22
Winter 1975 49
January 1975 14
February 1975 18
March 1975 15
April 1975 15
Winter 1975 62
May 1975 14
June 1975 I
Spring 1975 15
March 1975 12
April 1975 25
Winter 1975 37
May 1975 20
June 1975 I
Spring 1975 21
Center of 
Activity1
5869-50249
5879-50253
5878-50252
5874-50249
5873-50248
5876-50251
5873-50248
5873-50248
5868- 50243
5867- 50242
5869- 50243
5869- 50242
5868- 50242
5870- 50242
5870- 50242
5867- 50241
5869- 50244
5868- 50242
5871- 50246
5867- 50241
5869- 50246 
5869-50244 
5869-50244 
5869-50242
5869-50242
5869-50243
5868- 50242
5868- 50242
5869- 50242
5868-50241
Std. Dia. 
in Miles
Max. Distance from 
Winter Range Center 
of Activity in Miles
Average Distance 
Between Relocations 
in Miles
1.11 1.10 0.56
0.71 0.80 0.35
0.72 0.80 0.46
0.63 0.55 0.40
0.67 0.60 0.29
0.69 0.80 0.37
0.77 0.85 0.37
- 0.90 -
0.84 0.90 0.35
0.98 1.10 0.38
0.64 0.70 0.35 I
0.67 0.90 0.39 M
0.52 0.65 0.33 7
0.74 1.10 0.36
0.98 1.00 0.48
- 0.25 -
0.96 1.00 0.46
0.74 0.95 0.41
0.92 1.20 0.38
0.83 1.20 0.40
1.13 0.95 0.32
1.04 1.10 0.50
0.78 0.95 0.41
0.86 0.90 0.34
0.96 1.10 0.40
0.86 0.95 0.53
- 0.35
0.85 0.95 0.54
0.60 0.50 0.39
0.44 0.50 0.30
0.50 0.50 0.32
0.83 1.10 0.40
- 1.70 -
1.10 1.70 0.40
Table 37. Continued.
Tag No. Sex
Month or 
Season
No. of 
Obs.
Center of 
Activity1
Std. Dia. 
in Miles
Max. Distance from 
Winter Range Center 
of Activity in Miles
Average Distance 
Between Relocations 
in Miles
94 F March 1975 8 5869-50244 0.77 0.60 0.43
April 1975 24 5868-50242 0.46 0.50 0.28
Winter 1975 32 5869-50242 0.55 0.60 0.31
May/ 1975 18 5868-50242 0.76 1.00 0.34
Spring
95 F- April/ 1975 15 5870-50243 1.01 1.15 0.51
Lamb Winter
May 1975 20 5870-50243 0.92 0.95 0.38
June 1975 I ■ - - 0.40 -
Spring 1975 21 5870-50243 0.92 0.95 0.37
96 M Spring 1975 3 5867-50235 2.23 1.40
Coordinates based on 1000 meter grid system on U. S. Geological Survey Topographic Maps
-123-
Table 38. Locations of five lambing areas on the West Rosebud drainage 
during the springs of 1974 and 1975.
Number of
Year Lambs Map Coordinates1
1974 3 5952-50097
1975 I 5983-50098
1975 I 6000-50101
1975 I 5983-50078
1975 I 5983-50111
1Based on 1000 meter grid system on U. S. Geological Survey Topographic 
Maps.
Table 39. Mean percentage of use by month and season of each plant species used by bighorn 
sheep In the West Rosebud area. Trace (Tr) amounts are less than 0.5 percent. 
Numbers of feeding sites examined and instances of use are shown in parentheses.
March April Winter May June 1-14
(3) (6) (9) (10) (Z)
Taxa (2302) (6800) (9102) (10647) (1668)
Grasses and Grass- 33.2 47.0 43.5 79.4 84.2
like Plants
Agrovyron caninum 
AgropyitOn soribneri 
Agropyron spieatum 4.4 3.3 22.5 25.3
Agropyron spp. 
Agroetie eoabra
dr<ymue spp. 
Carex spp. 28.5 11.5 15.8 9.4 7.1
Daatylie glomerata 
Deeahartpeia atro-
2.3
purpurea
Deeahartpeia Tr Tr
aaeepitoea 
Feetuaa idahoeneie 16.9 12.6 18.5 8.3
Feetuaa ovina 4.6 1.2
Heeperoahloa kingii 
Junaue baltiaue
14.2 10.6 26.0
Koeleria orietata 1.1
Luzula vahlenbergii 
Poa spp.
Unknown
1.9 41.2
Forbs
Aahillea mille-
66.8 12.7 26.4 15.5 8.3
folium 
Alliur spp. Tr Tr Tr 0.6
Agoseris glauaa Ir
Anemone patene Tr 1.7
Antennaria spp. 
Apiaaeae 
Apoaywur andro-
0.9
'
saenii folium 
Aquilegia flaoeeaens 
Apniaa latifolia
Aptemisia fricida 3.9 2.9 0.6
Aster alpigenue 
Asteraaeae 
Astragalus :'c.riIIi- 
f  lexus
Spring
(12315)
June 15-30 
(3246)
July
(1435)
August
(986)
Summer
(9)
(5667)
October
(494)
November
(4)
(1019)
Fall
(1513)
80.0 82.9 25.9 37.1 60.5 78.9 83.3 81.9
9.3 5.3
2.0 Tr 14.0 4.6
22.9 15.1 8.7
Tr . 0.5 Tr 12.3 4.0
1.9 1.1
Tr Tr
9.1 29.3 4.9 15.3 20.7 Tr 37.6 25.4
Ir
1.7 Tr
5.3 1.3 38.8 26.1
17.1 1.4 0.8
1.6 Tr 0.5 0.8 1.2 i.i
22.5
Tr Tr
1.0 2.4 2.2 1.0 2.4 1.1 1.5
1.7 Tr
7.3 25.4 11.0 13.0 19.6 49.2 4.7 19.2
0.5 Tr Tr
14.5 13.1 40.0 51.9 26.6 21.1 16.5 18.0
Tr 1.0 Tr
Tr
Tr t 13.7 2.4
0.5 I
0.8 Tr Tr
Tr Tr
3.6 0.9
1.9 Tr
8.2 1.4
0.5
0.7 Tr
3.2 1.1
6.8 1.7
I
KJ
4>
I
Table 39. Continued
March
(3)
Iaxa (2302)
Forbs (cont.)
Baleanorrhiza 
eagittata 
Braeeiaaaeae 
Campanula rotundi- 
folia
Caetille^a oueiokii 
Ceraetium arvenee 
Ckrysopeie villoea 
Comandra umbel lata 
Delphinium bicolor 
Dodeoatheon pauai- 
' f  lorum
Dryas ootopetala 
Epilobium angusti- 
foliun
Erigeron spp.
Fabaoeae
Geum roseii 62.1
Fragaria virginiana
Heuohera oy Hndrioa 
Hydrophyllum spp.
Lilaoeae
Lloydia eerotina 
Lupinus argenteue 
Merteneia alpina 
Oxyria digyna 
Phlox hoodii 
Polygonum 
bietortoidee 
Potentilla diversi- 
folia
Potentilla spp.
Saxifraga bronchia lie 
Saxifraga spp. 0.8
Sedum spp.
Seneaio oanue
Seneaio araesuluB
Silene aoaulie 3.7
Solidago
rrieeourieneis
April Winter May
(6) (9) (10)
(6800) (9102) (10647)
June 1-14 Spring 
(2) (12)
(1668) (12315)
5.6 4.2 0.6 0.5
Ir Ir
Ir Ir Ir Ir Ir
Ir 0.5 Ir
4.0 3.5
Ir Ir
Ir Ir
0.7 Ir
15.7
1.7 1.5
Ir Ir
5.4 4.6
2.2 1.7 0.8 0.7
Ir
0.9
June 15-30 July August Summer October November Fall
(2) (5) (2) (9) (2) (4) (6)
(3246) (1435) (986) (5667) (494) (1019) (1513)
Ir Ir
Ir Ir
3.8 1.0
Ir Ir
Ir Ir
Ir Ir
0.6 15.9 2.9
3.2 1.0 1.0
Ir Ir
Ir Ir
0.5 Ir
5.5 1.4
0.5 Ir
Ir 1.3 Ir
0.7 Ir
0.6 Ir
0.9 Ir Ir
0.5 Ir Ir
0.6 Ir
Ir Ir
Ir Ir
5.6 3.2
1.9 Ir
7.9 2.0
2.9
I
Ir Ir H
NJ
Y1
2.5 1.0 1.5
13.3 9.0
0.6 Ir
13.4 4.4
0.8 1.9 1.5
5.1
Table 39. Continued
March April Winter May June 1-14 Spring June 15-30 July August Summer October November Fall
(3) (6) (9) (10) (2) (12) (2) (5) (2) (9) (2) (4) (6)
Taxa (2302) (6800) (9102) (10647) (1668) (12315) (3246) (1435) (986) (5667) (494) (1019) (1513)
Forbs (cont.) .
TuiKuxiriArn officinale Tr Ir
Trajnpoffon dubius Tr Tr Tr Tr
Trifolinm parryi 4.5 i.i
Trifolim spp. 4.5 0.6
Veronica womskjoldii 1.1 Tr
Viola spp. Tr Tr
Unknown Tr Tr Tr Tr Tr Tr 0.7 0.6 1.6 0.8 0.6 Tr
Shrubs 40.3 30.1 5.1 7.5 5.5 4.0 34.1 11.0 12.9 Tr Tr
Abies lasiocarpa Tr Tr
Acer glabriffi 0.9 0.5
Ara^-OBtaphijloa 1.7 1.0
uva-ur&i
Artemisia tridentata 39.2 29.3 0.7 0.6
Berberie repens Tr Tr
Phy Ilodoce 0.5 Tr
glanduli flora
Fhyeoaarpue 6.6 0.9 Tr 11.7 3.1
malvaceus
Prunus virginiana 1.1 0.8 3.8 0.9 3.4 Tr 7.0 1.9
Eibes eetos.m 0.6 0.6 0.9 0.5
Eosa acieularis 14.0 3.5
RubitS idaeus Tr Tr Tr Tr Tr
Salix spp. 1.0 Tr Tr
Vaccinium scoparium 10.3 1.8
able 40. Mean percentage of use by month and season of each plant species used by bighorn 
sheep in the Stillwater area. Trace (Tr) amounts are less than 0.5 percent. 
Numbers of feeding sites examined and instances of use are shown in parentheses.
Spring Summer
Jan. Feb. Mar. Apr. Winter May July Oct. Nov. Fall
(34) (8) (15) (9) (66) (14) (I) (I) (3) (4)
Taxa (17878) (5561) (6946) (6327) (36712) (9759) (114) (102) (724) (826)
Grasses and Grass-
like Plants 41.8 62.0 57.4 54.5 50.0 82.6 100.0 40.3 47.7
Agropyron inter- 37.3 13.0 16.0
medium
Agropyron spieatum 16.9 34.3 1.9 18.0 16.9 51.0 23.6 20.7
Agropyron traohy- 62.7 7*7 ,
oaulum H
N d
Agropyron spp.. Tr Tr 1.4 1.2 r
Agrostie soabra Tr Tr
Bouteloua gracilis Tr Tr
Bromus tectorum Tr . Tr Tr Tr Tr Tr 0.8 0.7
Bromus spp. Tr Tr
Calconovilfa 0.9 Tr 0.9 0.6 Tr
longifolia 
Carex spp. 2.4 15.4 3.2 3.4 4.7 3.6 Tr Tr
Elymus canadensis Tr ■ Tr
Equisetum spp. Tr Tr
Festuca idahoensis 1.4 Tr 18.5 17.1 7.1 2.4 1.0 0.8
Juncus balticus Tr Tr
Koeleria cristata 0.5 Tr 0.6 2.1 0.7 4.1
Phleum pratensis 0.6 Tr
Poa spp. 15.9 4.7 24.2 4.6 13.8 21.1
Sporobolus Tr Tr
airoides 
Stipa comata 0.7 5.9 0.9 1.2 1.6 Tr Tr
Typha latifolia 1.6 7.0 7.8 3.5
Unknown Tr 0.8 Tr
Table 40. Continued.
Spring Summer
Jan.
(34)
Taxa (17878)
Feb.
(8)
(5561)
Mar.
(15)
(6946)
Apr.
(9)
(6327)
Winter
(66)
(36712)
May
(14)
(9759)
July
(I)
(114)
Oct,
(I)
(102)
Nov.
(3)
(724)
Fall
(4)
(826)
Forbs 16.4 5.1 27.5 8.6 15.4 6.9 56.1 56.5 49.5
Agoser-Ls glauoa 0.7 Tr Tr
Atlium spp. Tr Tr Tr
Anemone patens - Tr
Antennaria spp. 2.9 Tr Tr Tr 1.5 Tr 21.8 19.1
Apooynum 0.5
androsaemifo Hum
Artemisia campestris 0.7 Tr Tr Tr Tr 0.7 0.6
Artemisia frigida 6.9 3.0 8.7 3.5 6.0 0.8 2.1 1.8
Artemisia 1.3 1.3 Tr 0.9 Tr 27.5 24.1
ludovioiana
Asteraoeae 0.7
Astragalus spp. Tr
Balsamorrhiza 0.7 Tr Tr 1.9
sagittata
Brassioaoeae Tr
Campanula 14.9 Tr Tr
rotundifolia
Castillega miniata 6.1
Cerastium arvense Tr Tr Tr Tr 0.5
Chrysopsis villosa Tr Tr Tr Tr Tr Tr Tr Tr
Cirsium spp. Tr Tr Tr
Comandra umbellata Tr
Delphinium bioolor Tr
Epilobium angusti- 2.6
folium
Erigeron spp. Tr Tr Tr
Fabaoeae Tr Tr Tr
Geranium 2.6
riahavdsonii
Table 40. Continued.
Jan.
(34)
Taxa (17878)
Feb.
(8)
(5561)
Mar. 
(15) 
(6946)
Apr.
(9)
(6327)
Winter
(66)
(36712)
Spring
May
(14)
(9759)
Summer
July
(I)
(114)
Oct.
(I)
(102)
Nov.
(3)
(724)
Fall
(4)
(826)
Forbs (cont.)
Eedysamm 25.4
sulphuresoens
Eevaoleim lavatum 0.9
Eeucheva cylindvica Tr Tr
Liqtvis punotata Tr Tr
Lupinus avgenteus 0.9 Tr Tr
Opuntia polyoantha Tr Tr Tr
Phlox hoodii 3.3 Tr 16.7 4.4 5.5 Tr 0.6 0.5
Potentilla spp. 1.1 1.0
Solidago Tr Tr 1.1 1.0
missouviensis
Tavaxaoum officinale • Tr
Tvagopogon dubius Tr Tr Tr
Unknown Tr Tr Tr 2.6 Tr Tr
Shrubs 41.8 32.3 15.0 36.9 34.4 10.5 43.9 1.9 1.7
Avtemisia 12.9 6.9 0.6 16.1 10.2 1.1 Tr Tr
tvidentata
Bevbevis vepens Tr Tr 1.3 Tr
Covnus stoloni- Tr Tr
feva
Pinus flexilus 0.7 Tr
Populus tvemuloides Tr Tr Tr
Populus tvicho- Tr Tr Tr
oavpa
Pvunus vivginiana 16.8 14.1 10.6 13.9 14.7 1.3
Pseudotsuga 9.2 1.4
menziesii
Rhus tvilobata 11.5 1.3 1.7 6.9 7.3 5.8 Tr Tr
-129-
Table 40. Continued.
Jan. Feb. Mar. Apr.
(34) (8) (15) (9)
Taxa (17878) (5561) (6946) (6327)
Shrubs (cont.) 
Ribes oereum Tr
Ribes montigenum 
Rosa aoioulavis
Satix spp. 
Symphorioavpos Tr
Tr
albus
Unknown Tr Tr
Mosses Tr 0.5 Tr Tr
Selaginetla densa Tr Tr Tr
Unknown 0.5 Tr
Spring Summer
Winter May July Oct, Nov. Fall
(66) (14) (I) (I) (3) (4)
(36712) (9759) (114) (102) (724) (826)
Tr
Tr
Tr
Tr
Tr
Tr
Tr
35.1 
Tr 8.8
2.2
0.7 0.6
Tr Tr
Tr Tr ,
1.2 1.1 ?
1.2 1.1
■tf N37aTSH9?6,rt W,Vmmr liimuiueS
3
»OVN0*2