Distribution, movements and habitat use of mule deer associated with the Bracket Creek winter range, Bridger Mountains, Montana by Harvey Evan Nyberg 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 Harvey Evan Nyberg (1980) Abstract: A study was conducted from March 1978 to April 1979 in the Bridger Mountains, Montana. Objectives were to determine the distribution, movements, habitat use, food habits and population characteristics of mule deer associated with the Brackett Creek winter range. A total of 114 mule deer were marked, 18 with radio collars. Mule deer generally occupied two seasonal ranges: winter-spring and summer-fall. Movements between these ranges were usually abrupt and direct and did not involve the use of holding areas. Mule deer were distributed throughout the winter range in early winter. From mid-January to mid-February most were concentrated on a primary use area comprising about 37 percent of of the total winter range. In winter, the movements of all but one of the deer centered on a series of subseasonal ranges. Polygon home ranges, standard diameters and average activity radii of 8 radio-collared mule deer averaged 12.9 km2, 3.3 km and 1.4 km, respectively, and differed significantly with those of mule deer on other Bridger Mountain winter ranges. During summer, mule deer were distributed thoughout the study area. Average polygon home ranges, standard diameters and average activity radii of 9 radio-collared mule deer were 2.9 km2, 1.5 km and 0.6 km, respectively and appeared to be larger than those reported on other Bridger Mountain ranges. During winter, sagebrush, grassland and agricultural cover types received 37, 43 and 14 percent of all recorded use. Mule deer selected the Douglas fir type during the early, severe portion of the winter. The sagebrush, agricultural and Douglas fir cover types were most important during summer, receiving 27, 23 and 18 percent, respectively, of recorded use by mule deer. Browse, forbs, and grasses received, respectively, 48, 33 and 19 percent of total utilization at winter mule deer feeding sites and accounted for 56, 9 and 35 percent by volume of the contents of 38 rumen samples, During summer, browse received 69 percent of recorded use and forbs and grasses 24 and 7 percent, respectively, at 5 mule deer feeding sites. Lincoln Index population estimates of 2352 and 1642 were calculated for early and late winter, respectively. The mid-summer population was estimated as at least 2866 animals. Densities of mule deer were calculated to be 12/km2, 23/km2 and 16/km2 during summer, early winter and late winter, respectively. On the primary winter range, the density of mule deer approached 62/km2. An initial fawn:doe ratio of 150 fawns:100 does was noted for 8 radio-collared does though fawn production for the entire herd was less. Overwinter mortality totaled about 10 percent of all adults and 58 percent of all fawns present in early winter or about 30 percent of the entire herd. The Brackett Creek population was dominated by young and middle-prime aged deer. Maximum ages of deer handled during the study were 10 1/2 for females and 8% for males. Examination of reproductive tracts indicated production below that observed in 1978 and below the long term average for mule deer in the Bridget Mountains.  STATEMENT OF PERMISSION TO COPY In presenting this thesis in partial fulfillment of the requirements for an advanced degree at Montana State University, I agree that the Library shall make it freely available for inspection. I further agree that permission for extensive copying of this thesis for scholarly purposes may be granted by my major professor, or, in his absence, by the Director of Libraries. It is understood that any copying or publication of this thesis for financial gain shall not be allowed without my written permission. Signature Date Z ( Zj DISTRIBUTION, MOVEMENTS AND HABITAT USE OF MULE DEER ASSOCIATED WITH THE BRACKETT CREEK WINTER RANGE, BRIDGER MOUNTAINS, MONTANA by HARVEY EVAN NYBERG A thesis submitted in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE in Fish and Wildlife Management Approved: JffiQiirperson, Graduate Committee rad, r Department Graduate De^n MONTANA STATE UNIVERSITY Bozeman, Montana January, 1980 ill ACKNOWLEDGEMENT I wish to express my sincere appreciation to the following for their contributions to this study: Dr. Richard J . Mackie, Montana State University who directed and aided in the study; Dr. William Gould and Dr. Robert L. Eng, for review of the manuscript; Mr. James Stradley, Gallatin Flying Service, "for his aviation skills and assis­ tance in aerial deer surveys; Mr. David F. Pac, Montana Department of Fish, Wildlife and Parks, for assistance in trapping deer and other aspects of the study; Dr. Henry Jorgensen, Montana Department of Fish, Wildlife and Parks, for assistance in habitat analysis; Mr. Terry Lonner, Montana Department of Fish, Wildlife and Parks, for assistance in computer analysis of data; Dr. John Weigand, Research Bureau Chief, and Mr. Arnold Foss, Regional Wildlife Manager, Montana Department of Fish, Wildlife and Parks, for support and use of equipment and facili­ ties; and local landowners, especially Mr. and Mrs. George Leffingwell, Mr. and Mrs. Hank Leffingwell, Mr. Donald Stafford, Mr. Orland Peckenpaugh, Mr. Richard Scott, Mr. Lawrence Lee, Mr. Edward Skillman, Mr. Pehr Anderson, Mr. Kenneth Johns, and the Brackett Creek Grazing Association for their hospitality and cooperation. I also thank my wife, Kathy, and son, Eric, for their patience and support throughout my academic career. The author was supported by the Montana Department of Fish, Wildlife and Parks under Federal Aid Projects W-120-R-9 & 10. TABLE OF CONTENTS . Page V I T A ............ ii ACKNOWLEDGMENT ............................................ iii TABLE OF CONTENTS.......................................... iv LIST OF TABLES ................... ' . ...................... v . LIST OF FIGURES..................... viii ABSTRACT . ........... '..................................... x INTRODUCTION .............................................. I DESCRIPTION OF THE STUDY A R E A ....................... 3 METHODS ......................... '16 Habitat Analysis ...................................... 16 Deer Trapping ......................................... 17 Movements, Distribution, Habitat Use ........ . . . . 17 Food H a b i t s ..................... 18 Population Characteristics ........................... 19 Deer Harvest..................................... 19 RESULTS ....................... . . . . . . . . . . . . . . 20 Movements, Distribution, Home Ranges . . . . . . . . . . 20 Associations Between Individual Marked Deer ........ 32 Habitat Use ■......................... 33 Food Habits ........................................... 38 Population Characteristics ........................... 45 DISCUSSION AND CONCLUSIONS......................... . . . 59 APPENDIX .......... ............. . . . . . . . . . . . . ■ 75 LITERATURE C I T E D ......................................'. . 101 V LIST OF TABLES Table Page 1. Vegetational and physiographic characteristics of the major ecological cover types on the Brackett Creek winter range . . . .................................... 8 2. Climatological data for two weather stations established on the Brackett Creek winter range during winter 1978-79 and for the U. S. Department of Commerce weather station, Wilsall 8ENE, MT .................... . . . . . . . . . 14 3. The seasonal polygon home range sizes (km2), standard, diameters (km) and average activity radii (km) of radio- collared mule deer on the Brackett Creek study area . . - 23 4. Winter home range sizes (km2), standard diameters (km) and average activity radii (km) of 8 neckbanded mule deer relocated more than 10 times each during the 1978- 79 winter on the Brackett Creek winter range .......... 24 5. Coefficients of association among marked deer on the Brackett Creek study area during 1978-79 .............. 32 6. The percentages of. all mule deer and marked mule deer using major ecological cover types on the Brackett Creek study area by months during 1978-79 ............ 36 7. Monthly percentages of use, January-March, of the major forage classes derived from observations at 23 mule deer feeding sites and from 38 rumen samples on the Brackett Creek study area during 1979 ................... .. 38 8. Percentage use of forage species by cover types and months at 23 mule deer feeding■sites examined on the Brackett Creek winter range during 1978-79. Trace amounts are less than 0.5 p e r c e n t .................... 40 9. Instances of use, aggregate percentages of use and constancy of use of forage species by months at 4 mule deer feeding sites examined on the Brackett Creek study area during 1978. Trace amounts are less than 0.1 per­ cent per month and 0.5 percent of total recorded use . . 44 vi Table Page 10. Sex and age classifications of the Brackett Creek mule deer herd obtained from early and late winter helicopter survey flights .......................................... '46 11. Lincoln Index estimates of the Brackett Creek mule deer population during winter, 1978-79 . . . . .............. 46 12. Sex and age classifications of mule deer on the Brackett Creek study area by months during 1978-79 .............. 48 13. Reproductive performance of 11 radio-collared mule deer does on the Brackett Creek study area during 1978 . . . . 49 14. Sex and estimated age of deer found dead on the Brackett Creek winter range during 1978-79 ........ . . . . . . . 51 15. Cause of death for 58 mule deer found on the Brackett Creek winter range during 1978-79 ...................... 52 16. Description of deer believed killed by domestic dogs on the Brackett Creek winter range during the 1978-79 winter. 54 17. Vegetational and physiographic characteristics of cover types present on the Brackett Creek study area . . . . . . . 76 18. Key to four letter plant species names used in Tables I and 1 7 ........ . . . . . . . . . . . . . . . . . . . . . 80 19. Sex and age description and status of 114 mule deer marked on the Brackett Creek winter range during 1978 and 1979 . 83 20. Maximum, minimum and average distances (km) between aerial relocations for radio-collared mule deer does bn the Brackett Creek study a r e a ............................ . 87 21. Daily polygon home range size (km2), standard diameters (km), average activity radius (km) and minimum, maximum and average distance between relocations of marked mule deer, 1978-79 ........................................... 88 22. Polygon home range sizes (km2), standard diameters (km) ■ and average activity radii (km) for deer followed for two-day periods, during 1978-79 . . . . ................ 90 Table vii 'Page 23. Percent by volume of the forage species found in rumen samples obtained from 38 mule deer found dead on the Brackett Creek winter range during 1979, by months. Trace amounts are less than 0.5 percent . . . . . 93 24. The sex and age composition of the Brackett Creek mule deer herd based on early winter (December) helicopter surveys . ............. 95 25. Seasonal polygon home range sizes (km2), standard diameters (km) or average activity radii (km) from various- studies of radio-collared mule deer in various types of habitats............................................ 96 26. The density of mule deer on winter ranges in the Bridger Mountains ................... 100 viii . LIST OF FIGURES' Figure Page 1. Map of the Bridger Mountains complex showing major features and location of the study area ............. 4 2. Map of the study a r e a ......................... .. 5 3. Aerial view of the foothills winter range ............ 6 4. Distribution of ecological cover types on the Brackett • Creek, winter range . . . .............................. 9 5. Distribution of the polygon home ranges of 8 radio- collared mule deer does on the Brackett Creek winter range during 1978-79 and outline of the borders of the total and primary winter ranges ................... 21 6. Patterns of use and average activity radii (km) of subseasonal ranges occupied by radio-collared mule deer on the Brackett Creek winter range during 1978-79. 24 7. Percent of day time active for marked deer observed for full day periods during winter 1978-79 . . . . . . 28 8. Percent of time active during mid-day, 1000-1400 hours, for marked deer observed for full day periods during winter 1978-79 ........................... ............ 28 9. Distribution during summer of polygon home ranges of 10 radio-collared mule deer does from the Brackett Creek study area and one radio-collared doe from the Schafer Creek study area .......... . . . . . . . . . 29 10. Yearlong trends in percentages of mule deer using the major ecological cover types recognized on the Brackett Creek study a r e a ..................................... 33 11. Habitat use by months by mule deer on the Brackett Creek winter range for fall and winter determined by combined ground and aerial observations (see text) . . 34 12. The distribution of fawn deaths for which a date could be established during the winter of 1978-79 . . . . . . 53 I Figure ix 13. The sex and age composition of the Brackett Creek mule deer herd based on data from trapped deer and carcasses found on the winter range during 1978-79 . . . 14. Total winter polygon home range and polygons of sub- seasonal ranges of mule deer doe 4108 in 1978-79 . . . . 15. The repetitious pattern of habitat use exhibited by radio-collared doe 2128 in early winter 1978-79 .• • • 16. The activity patterns of marked mule deer observed for full day periods on the Brackett Creek winter range during 1978-79 . . . . ........................... Page 57 91 . 92 ■ 97 X ABSTRACT A study was conducted from March 1978 to April 1979 in the Bfidger Mountains, Montana. Objectives were to determine the distribution, movements, habitat use, food habits and population characteristics of mule deer associated with the Brackett Creek winter range. A total of 114 mule deer were marked, 18 with radio collars. Mule deer generally occupied two seasonal ranges: winter-spring and summer-fall. Movements between these ranges were usually abrupt and direct and did not involve the use of holding areas. Mule deer were distributed throughout the winter range in early winter. From mid-January to mid-February most were concentrated on a primary use area comprising about 37 percent of of the total winter range. In winter, the movements of all but one of the deer centered on a series of subseasonal ranges. Polygon home ranges, standard diameters and average activity radii of 8 radio-collared mule deer averaged 12.9 km2, 3.3 km and 1.4 km., respectively, and dif­ fered significantly with those of mule deer on other Bridger Mountain winter ranges. During summer, mule deer were distributed thoughout the study area. Average polygon home ranges, standard diameters and average activity radii of 9 radio-collared mule deer, were 2.9 km2, 1.5 . km and 0.6 km, respectively and appeared to be larger than those re-, ported on other Bridger Mountain ranges. During winter, sagebrush, grassland and agricultural cover types received 37, 43 and 14 percent of all recorded use. Mule deer selected the Douglas fir type during the early, severe portion of the winter. The sagebrush, agricultural and Douglas fir cover types were most important during summer, receiv­ ing 27, 23 and 18 percent, respectively, of recorded use by mule deer. Browse, forbs, and grasses received, respectively, 48., 33 and 19 percent of total utilization at winter mule deer feeding sites and accounted for 56', 9 and 35 percent by volume of the contents of 38 rumen samples, During summer, browse received 69 percent of recorded use and forbs and grasses 24 and 7 percent, respectively, at 5 mule deer feeding sites. Lincoln Index population estimates of 2352 and 1642 were calculated for early and late winter, respectively. The mid-summer population was estimated as at least 2866 animals. Densities of mule deer were calculated to be 12/km2, 23/km2 and 16/km2 during summer, early winter and late winter, respectively. On the primary winter range, the densi­ ty of mule deer approached 62/km2. An initial fawn:doe ratio of 150 fawns:100 does was noted for 8 radio-collared does though fawn produc­ tion for the entire herd was less. Overwinter mortality totaled about 10 percent of all adults and 58 percent of all fawns present in early winter or about 30 percent of the entire herd. The Brackett Creek popula­ tion was dominated by young and middle-prime aged deer. Maximum ages of deer handled during the study were 10^ for females and 8% for males. Exam­ ination of reproductive tracts indicated production below that observed in 1978 and below the long term average for mule deer in the Bridget Mountains. INTRODUCTION In the Bridger Mountains, Montana, mule deer (Odocoileus Tiemionus Rafinesque) occupy three broadly different types of winter ranges. Ranges along the west slope comprise a narrow band of steep, south—and southwest-facing, open slopes dissected by timbered draws and canyon walls. East side winter ranges consist of extensive open ridges and rolling sagebrush-grass plains, with timber restrict­ ed to certain stream bottoms and north-facing slopes at the upper margins. A "breaks" type winter range, characterized by closely interspersed, open ridges and brushy to semi-open—timbered draws and creek bottoms, occurs along the north end. General population studies, conducted throughout the Bridger Mountains' since 1974 (Mackie et al, 1978), have indicated that mule deer population characteristics differ according to winter range type. Populations associated with east side and north end winter ranges have consis­ tently included higher and more variable proportions of fawns and fewer adult males than those associated with west slope winter ranges. The ecology of mule deer populations associated with west slope winter ranges has been studied intensively (Wilkins 1957, Schwarzkopf 1973, Bucsis 1974, Hamlin 1974, Morton 1976, Pac 1976, Mackie et al. 1976, Mackie and Stewart 1976j Mackie and Knowles 1977, Mackie, Pac and Jorgensen 1978, 1979, Steerey 1979, Youmans 1979). This study represents the first intensive investigation of a mule deer population associated with an east side winter range. Specific objectives were 2 to determine the distribution, movements, food and range use habits and population characteristics of the Brackett Creek mule deer herd and compare results with findings from other investigations of mule deer in the Bridger Mountains and elsewhere. Field studies began in March 1978 and were conducted full time from June 1978 through March 1979. DESCRIPTION OF STUDY AREA The Bridger Mountains are located in southwestern Montana immediately northeast of Bozeman (Fig. I). The main range extends in a gentle arc northwesterly for approximately 37 km and is attended by the Elkhorn, Battle and Bangtail ridges. The study area (Fig. 2) comprised the north end of the Bangtail Ridge or plateau and its adjoining easterly foothills, a land area of approximately 31,500.hectares. The precise boundaries were Bfidger Canyon on the west, the Brackett Creek road on the north, the Shields. River on the east and an imaginary line connecting the Stone Creek- School Gulch divide and the Bangtail Creek-Willow Creek divide on the south. The Bangtail Ridge extends approximately 19 km southeast from the confluence of the three forks of Brackett Creek and is composed of variously tilted Morrison Formation shales and sandstones. The foothills are characterized by alternating sagebrush valleys and rocky sandstone outcrop ridges or hilltops and dissected by numerous intermittent streams flowing to the northeast (Fig.,3). Elevations varied from 2,435 m on the Bangtail Ridge to 1,402 m near the confluence of Kay Creek and the Shields River. The study area is drained in three directions by nine major continuously flowing streams. Approximately 15 percent of the area was public land owned and administered by the Uv S. Forest Service, Gallatin National Forest. National Forest lands occurred in a checkerboard pattern at higher 4 MEAGHER CO GALLATIN CO LEGEND CREEK DIRT ROAD PAVED HIGHWAY COUNTY LINE MOUNTAIN PEAK CITY MULE DEER WINTER RANGE BlACKTAIl MT WINTER RANGE X / SCALE |W ILSALl h BATTLE RIDGE Y fW lN T E R RANGE BRACKETT CREEK WINTER WINTER gf--- C lE I l l IiieiIOii Figure I. Map of the Bridget Mountains complex showing major features and location of the study area. To l— -tb­ it IV CR Uvmgston C20mi)L E G E N D PIVtD ROAD UNPAVED ROAD STREAM Figure 2. Map of the study area (including major continuous streams, trails, and topographic points). 6 Figure 3. Aerial view of the foothills winter range. 7 elevations along Bangtail Ridge. Public access to this portion of the study area, which served primarily as summer-fall range for mule deer, was limited to three seasonal truck trails. One public road, Calcite road, occurred on the eastern part of the winter range. Elk (Cervas canadensis) commonly occur on the Bangtail Ridge during summer and fall. Small numbers of moose (AIces aloes shivasli) may use the area throughout the year. White-tailed deer {Odocoileus Vivginianus) occur along major streams during spring, summer and fall and along the Shields River, on the eastern boundary of the study area, throughout the year. The entire area was grazed by cattle, while a portion of the summer range was also grazed by one band of approximately 2,000 domestic sheep. Thirty-eight broad vegetative cover types (see Appendix, Table 17) have been tentatively delineated on the study area (Jorgensen, unpubI. data). For this study, these were grouped into seven broad ecological types (Table I and Fig. 4) based on general vegetative, physiographic and topographic similarities: Grassland Type.— A grassland type occurred on rocky, sandstone derived soils generally below 1,830 m. This type typically occupied hilltops or ridgetops and upper slopes between sagebrush dominated valleys (Fig. 3). It was found on all aspects, but especially on the north­ west, and on slight to moderate slopes. The major grasses were blue- bunch wheatgrass (Agropyron spicatwn), Idaho fescue (Festuca Table I. Vegetational and physiographic characteristics of the major ecological cover types on the Brackett Creek' winter range. Cover Sub Slope Elev Maj or Plant Species Present ' Type Strata (Degrees) Aspect (m) Grasses Forbs Shrubs Trees Grassland SS-RS1 . 0-20 2 N W ' 1524-1829 Agsp, Feid4 Basa, Chvi " Artr, Rosa spp Pifl . (0-40+) (all) Koma, Stco Luar, Arfr ■ Prvi, Jusc Sagebrush SS-NRS 10-20 NW, SE 1524-1829 Agsp, Koma, Luar, Anro, Artr, Jusc Psme, Pifl (0-40+) (all) (to 1905) Feid, Popr Trdu, Astrag spp Amal, Putr Limber SS 20-30 Var S 1524-1601 Agsp, Koma, Acmi, Basa, Jusc, Artr Pifl, Psme Pine RS (0-40+) Orhy, Brte Heun, Meof Rhtr, Oppo Douglas Var. 0-40 Var NSe 1524-1829 Feid, Koma, Luar, Ciar, Artr, Jusc, Psme Fir3 SE Popr, Agsp Taof, Arco 2 Ribes, Rowo Swales a) NRS 10-20 Var NSE 1524-1329 Popr, Phpr, Gevi, Mof i, Symph. spp, Psme (0-40+) Elci Deoc, Ciar Artr, Rowo ‘ b) NRS 5-20 Var N&E 2134-2363 Feid, Carex spp, Gevi, Acmi Psme, Pico (0-30) Brea, Agca Coli Creek NRS 0-10 Various 1524-1829 Popr, Phpr, Gevi, Salix, Picea Bottom Aster spp Alin Psme Brea, Elci Ciar, Senecio spp Cost, Potr Agricultural NRS-)- 0-20 Various 1524-1829 Brin, Dagl, Mesa RS Hovu, Trae 1 SS=Sandstone, RS=Rocky Soil, NRS=Non-rocky Soil. 2Usual condition (total range). 3Douglas fir type on winter range only, on summer range see Appendix, Table 17. lfSee Appendix, Table 18 for key to four letter plant species names. Figure 4. Distribution of ecological cover types on the Brackett Creek winter range. XO ■idahoensi-s), prairie June grass (JLoeterda macrantha), and needle and thread (Stipa comata) . Arrowleaf balsamroot (Balsamorrhisa saggittata), hairy goldenaster (Chryopsds villoas), silvery lupine (Lupdnus argenteus) and fringed sagewort (,Artemdsda frdgdda) were the most • important forbs noted. Big sagebrush (Artemdsda trddentata), rose (Rosa spp.), chokecherry (Prunus vdrgdnda) and Rocky Mountain juniper (Jundperus soopulornrn) were the most common shrubs present. Limber pine (Pdnus ftexds) was present on many of the more rocky sites of this type as scattered individuals. Sagebrush Type.— Sagebrush cover types were associated with non-rocky soils derived from sandstones, usually below 1,830 m elevation. The sagebrush type occurred on all slopes and all exposures, but was most common on 10-20 degree slopes of northwest and southeast aspect. Bluebunch wheatgrass, prairie junegrass, Idaho fescue and Kentucky bluegrass (Poa pratensds) were the most important grasses. The most important forbs were silvery lupine, rosy pusseytoes (Antennarda rosea), salsaify (Tragopogon dubdus) and milkvetch (Astragulus spp.). Big sagebrush was the most important shrub followed by Rocky Mountain • juniper and western serviceberry (Ametanohder alndfolda). Antelope bitterbrush (Purshda trddentata) occurred on sites of this type on the north end of the study area only. Douglas fir (Pseudotsuga mensesdd) and limber pine occurred as scattered individuals. Ldmber Pdne Type.— Limber pine cover types were restricted to moderately 11 steep (20-30°) rocky (sandstone), usually south-facing slopes at elevations below 1,600 m on the winter range. These sites were dominated by limber pine. Rocky Mountain juniper, big sagebrush and bluebunch wheatgrass. Douglas fir trees were usually present. Prairie junegrass, Indian ricegrass (Oryzopsis hymenoides) and cheatgrass (Bromus tectovwn) were other important grasses. A variety of forbs were found, especially common yarrow (Achiltea mtVlefoUWri) y arrowleaf balsamroot, Rocky Mountain helianthella (,HeHantheHa Uniflovas) and yellow sweetclover (Melilotus Offtatnaltss). Skunkbush sumac (Rhus tvtlobata) and prickly pear cactus (Opuntta polycantha) were also important shrubs. Douglas Ftv Type.— The Douglas fir type was restricted on the winter range primarily to certain stream bottoms and slopes of northerly aspect. On intermediate and summer ranges it was the dominant type, occurring as various cover types (Appendix, Table 17) on all slopes and exposures and at all elevations. On winter range sites, Idaho fescue and, occasionally, big sage­ brush were also dominant species. Other important grasses included prairie junegrass, Kentucky bluegrass and bluebunch wheatgrass. Silvery lupine, Canada thistle (Ctvstum avvense), dandelion (Tavaxaaum Offtctnales) and ballhead sandwort (Avenaxta congesta) were the most important forbs. Other important shrubs were Rocky Mountain juniper, woods rose (Rosa woodstt) and gooseberry (Rtbes spp.). Individual 12 cover types occurring at higher elevations were vegetationally diverse, depending upon local site conditions and other factors. Vegetative and physiographic characteristics of these are described in Appendix, Table 17. Swale Type.— The swale type included moist meadows and brushy draws •. which differed somewhat in vegetational composition by elevation. At higher elevations (2,135-2,360 m) the type was found on slight to moderate (0-20°) slopes of various northerly and easterly exposure and presented a general grass-forb aspect. Idaho fescue, sedges (Carex spp.) and sticky geranium (Geranium viscosissimum) usually were dominant species. Other common grasses included California brome (Bromus oavinatus) and bearded wheatgrass (Agropyron oaninum). Timber oatgrass (Danthonia intermedia)- was also frequently present. Common yarrow and narrow-leaved collomia (Collomia linearis) were ■ important forbs. Scattered Douglas fir and lodgepole pine (Finns oontorta) trees usually were also present. Swales of lower elevations exhibited a shrubby aspect, dominated by snowberry (Symphoricarpos spp.).and exotic grasses including Kentucky bluegrass and timothy (Phleum pratense). Basin'wildrye (Elymus einereus) was also abundant while important forbs included sticky geranium, wild bergamot (Monarch, fistulasa), western larkspur (Delphinium ocoidentale) and Canada thistle. Douglas fir trees again were usually present. Creek Bottom Type.— Creek bottoms throughout the study area were 13 dominated by willow (Salix spp.), mountain alder (Alnus -inoana) and a wide variety of exotic and native grasses and forbs characteristic of moist sites. Red-osier dogwood (,Covnus stolon-ifeva) and aspen (PopuZus tvemuZoides) were common shrubs. The most important grasses were Kentucky bluegrass, timothy, California brome and basin wildrye. Sticky geranium, aster (Aster spp.), Canada thistle and groundsel (Seneoio spp.) were the most important forbs. Douglas fir and occasionally spruce (Pioea spp.) trees were also found in creek bottoms. Agri-ouZturaZ Type.— The agricultural type included grainfields and hayfields occurring at elevations below 1,830 m. The most common plant species present were smooth brome (Bvomus -Lnerntis), orchard- grass (Daotyt-is gZomevata), barley (Hordeum vuZgare) and alfalfa (Medicago sati-vd). Climatological data for the 1978-79 winter and long term means are presented in Table 2. Although data from the Wilsall station may not be entirely applicable to conditions on the study area, they are presented to show general trends and the relative severity of the 1978-79 winter. The 30-year average annual temperature at Wilsall 8ENE is 5° C. January is usually the coldest month with an average temperature of -6.9° C, while July is warmest averaging 16.7° C.. Average annual precipitation at Wilsall 8ENE is 52 cm. An average of 223 cm of snow falls during the November-April period with greater Table 2. Climatological data for two weather stations established on the Brackett Creek winter range during winter 1978-79 and for the U. S . Department of Commerce weather station, Wilsaill 8ENE, MT. Month Sta Temperature °C Precipitation cm Snowfall cm Max. Snow Depth cm Days on Ground November Wil -3.8/-0.8/301 5.6/2.9/20 82.6/30.7/20 40.6/16.5/19 25/9.1/14 Lef -2.8 25 Pek -5.9 25 December Wil -10.1/-4.6/30 3.0/2.3/20 35.6/42.4/19 50.8/29.2/15 30/26.3/16 Lef -10.6 31 Pek -7.8 31 January Wil -12.8/-6.9/30 2.3/2.5/21 45.7/43.9/20 71.1/43.2/16 31/30.5/15 Lef -13.0 41.7 31 Pek -11.1 28.2 31 February Wil -5.2/-3.9/30 2.5/1.9/21 50.8/30.7/20 — /37.3/17 11/26.9/15 Lef -4.2 45.7 Pek -4.4 March Wil -.4/-2.2/30 3.5/3.4/21 33.0/45.7/19 66.0/42.7/17 — /29.3/12 Lef o.o '51.1 Pek -0.6 19.8 April Wil 1.0/3.8/30 3.4/4.4/21 12.7/29.0/19 45.7/24.6/19. 0/11.1/14 Lef 4.1 4.6 0.0 0.0 0.0 Pek 3.6 0.0 0.0 . 0.0 Data for 1978-79 winter/long term average/number of years averaged. I 15 than 2.5 cm of snow on the ground for an average of 133 days. The climatological data for the 1978-79 winter indicate that during the November 1978-February 1979 period temperatures were much below average. Snowfall was above average in November arid average to above average from December through February, These conditions combined resulted in much greater than average snow depths. Weather conditions moderated to provide a period of rapid melting after mid- February and the winter range was relatively snow free during late winter. I ■ I I METHODS Habitat Analysis Vegetational cover and habitat types on the study area were defined by Jorgensen (1977) in conjunction with Bridget Mountain mule deer habitat studies. The habitat sites selected for study appeared as recognizable units on air photographs. Each unit was visited and measurements of its elevation, slope, aspect and substrate were recorded. The cover type of a site was designated by visually deter­ mining the two plant species with the greatest canopy coverage. The remaining plant species were listed in their order of apparent abundance. Additional habitat units that appeared from air photos to be similar to those initially chosen for study were visited and described to determine the reliability of cover typing from aerial photos. Habitat types were assigned following Pfister et al. (1974) for forested habitats and Meuggler and Handl (1974) and Jorgensen (1977) for grassland and shrubland habitats. Plant names followed Hitchcock and Cronquist (1973) whenever possible or Booth (1972), Hahn (1973) or Booth and Wright (1959). Climatological data for the winter range were obtained from two Department of Fish, Wildlife and Parks’ weather stations, which were established on the study area in November 1978, and the U. S. Depart­ ment of Commerce, weather station at Wilsall 8ENE, MT. The Department of Fish, Wildlife and Parks' weather stations consisted of standard rain gauge, recording hydrothermograph and anemometer. 17 Deer Trapping A total of 112 mule deer (see Appendix, Table 19) were marked on the study area during two trapping periods. During March and. April 1978, 31 deer were captured using cannon nets as described by Mackie et al. (1976). In early March 1979, 81 deer were captured by a helicopter drive net technique. Twelve of the deer trapped in 1978 and 6 of those captured in 1979 were fitted with radio-transmitter collars. The others were marked with 4-inch vinyl neckbands of Armortite materials bearing Tuff-flex painted symbols. In addition, two fawns captured by hand during the 1978 summer were marked with colored ear flags. Movements, Distribution, Habitat Use The movements, distribution and habitat use of mule deer were determined by aerial and ground observations. Aerial surveys using Piper supercub aircraft were made at approximately weekly intervals to relocate radio-collared and other marked animals. Data recorded for all observations included: time, vegetation cover type, slope and aspect. Group size, composition and any specific markings were I recorded for all visual observations. All relocations of marked deer were precisely marked on aerial photos. On some flights during winter when large numbers of deer (up to 700) were observed, only the general locations of groups of unmarked deer were recorded. Seasonal dates used in analysis of movements and habitat use were based on mule 18 deer activity according to the method described by Steerey (1979). Locations of observed marked mule deer were converted into Universal Transverse Mercator coordinates to facilitate computer analysis of data. Detailed data on winter habitat use were obtained by intensive ground observations of individual marked deer for one or two day periods at irregular intervals. Locations and routes of travel were recorded on large scale aerial photos. Daily and seasonal polygon home ranges (Mohr 1947), standard diameters (Harrison 1958) and average activity radii (Hayne 1949) were calculated. Average activity radii were used for statistical comparisons whenever possible to prevent bias due to differences in sample sizes. Indices of association (Knight 1970) were calculated for selected pairings of individual marked deer. Food Habits The food habits of mule deer were determined by visiting 28 recent feeding sites and recording instances of plant use as described by Cole and Wilkins (1958). Supplementary data were provided by analysis, following Wilkins (1957), of 38 rumen samples collected from deer found dead on the study area. Forage preferences were assessed subjectively by consideration of extent of use in relation to occur­ rence at each site. . 19 Population Characteristics Early and late winter helicopter sex and age classification surveys (Mackie et al. 1978) and two late winter fixed-wing age classification surveys provided information on population composi­ tion and for computation of Lincoln indices (Overton and Davis 1969) of population size. Additional data concerning population composi­ tion, fawn production and mortality were gathered by sex and age classifications of deer observed, found dead and handled during trapping operations. Deer Harvest Information on mule deer harvest was gathered from hunter questionnaires returned to three voluntary check boxes on the area, field contacts with hunters and conversations with local landowners. Landowners were contacted prior to the opening of the general hunting season to determine potential hunter access.. RESULTS Movements, Distribution, Home Ranges Winter-Spring (25 December 1978 to 10 May 1979) Di-StTibution During early winter of 1977-78 and 1978-79, mule deer were distributed across an area of approximately 10,200 hectares within an elevational range of 1,402 to 1,830 m (Fig. 5). This total winter range (Fig. 5) included the Brackett Creek drainage below Miles Creek and all but the timbered upper portions of Canyon and Bangtail Creeks. Mule deer distributional changes on the winter range were not e followed during the 1977-78 winter. During 1978-79, however, most of the mule deer population became concentrated along lower Brackett Creek below Gobblers Knob by mid-winter. This Primary or Critical Winter Range (Fig. 5) encompassed approximately 3,750 hectares or about 37 percent of the total winter range area. Concentration on the primary use area was most evident from mid-January to mid-February, a period of about 30 days. Thereafter, deer again became dispersed across the entire area as the weather moderated and snow depths decreased on the winter range. Mule deer occupied the Brackett Creek winter range for a period of approximately 6 months. The nine radio-collared mule deer arrived on the winter range in 1978-79 during a period of 3 months, November- January, although all but one (No. 2118 which arrived on 26 January 21 ,Brackett--Cr anyon__Cr LEGEND DEER NO 103B STREAM -----------< TOTAL WINTER __ RANGE PRIMARY WINTER RANGE - - - - - - SCALE IkmLEGEND DEER NO. 2068 STREAM — TOTAL WINTER ... PRIMARY WINTER RANGE Figure 5. Distribution of the polygon home ranges of 8 radio- collared mule deer does on the Brackett Creek winter range during 1978-79 and outline of the borders of the total and primary winter ranges. 22 1979) were there by 29 December 1978. Departure of radio-collared deer from the winter range generally occurred during a 25-day period from mid-May to early June. In 1979, one radioed doe moved off the winter range in late April while a radioed buck moved off the winter range on 15 July (Rosgaard, pers. comm.). Movements and Eome Ranges Seasonal polygon home range sizes, standard diameters and average activity radii of 12 radio-collared and 8 neckbanded mule deer are presented in Tables 3 and 4, respectively. The seasonal maximum, minimum and average distances between aerial relocations of radio- collared deer are presented in the Appendix, Table 20. The movements of all but one of the eight radio-collared does on the winter range centered around two or more distinct "activity centers" (subseasonal home ranges). Generally, those reflected their distribution during early winter (January to mid-February), late winter (mid-February to mid-March) and spring (mid-March to mid-May) periods. Movements about each activity center were charac-, terized by distinct patterns of range use which were related to weather and snow conditions. The length of time that the activities ■ of individual deer centered around each activity center varied greatly; however, four patterns were apparent (Fig. 6). These included use about a single activity center during the entire winter, use of separate early.winter, late winter and spring ranges, use of a Table 3. The seasonal polygon home range sizes (km2) activity radii (km) of radio-collared mule area. , standard diameters deer on the Brackett (km) i Creek and average study Deer Summer 1978 Winter 1978--79 # HR1 SDl AARl HR SD AAR 2038 1.33 1.12 0.52 19.45 6.11 2.79 2068 0.52 0.84 0.39 13.83 2.82 0.91 2108 2.882 1.70 0.74 0.87 1.35 0.59 2118 5.06 1.81 0.81 9.42 2.42 0.89 2128 0.47 0.65 0.27 8.85 2.40 0.96 4078 -- 3 —- — — 15.05 6.26 2.91 4088 1.204 * 6 --- --- 11.97 4.21 1.81 4098 12.333 3.85 1.34 6.63 2.02 0.82 4108 1.39 1.30 0.61 27.39 4.46 1.97 4118 3.226 1.40 0.56 — — — 4128 1.33 1.33 0.60 5.26 2.02 0.87 4018 0.877 0.88 0.39 — — — X 2.94 1.49 0.62 12.85 3.31 1.38 S 3.599 0.908 0.300 7.375 1.472 0.730 N 11 . 10 10 8 8 8 1HR=Polygon Home Range, SD=Standard Diameters, AAR=Average Activity Radius 2Radio failed 6-22-78, included here because it remained in an area where it was frequently observed. 34078 left the study area in June 1978 and wasn't resighted until December 1978 on Wilsall winter range. Winter range data not included in statistics. ^4088 had two activity centers 7.7 km apart. Polygon HR is the sum of the area at each activity center, other parameters not calculated. 34098 was a yearlong resident of the winter range, seasonal range sizes were calculated on the basis of herd mean season dates. ' - 64118 killed on summer range 11-24-78. 74018 marked on Schafer Creek winter range, summered on Brackett Creek study area. 24 Table 4. Winter home range sizes (kn?), standard diameters (km) and average activity radii (km) of 8 neckhanded mule deer relo­ cated more than 10 times each during the 1978-79 winter on the Brackett Creek winter range. Deer it Sex HR SD AAR 0048 Cf 8.77 2.19 0.89 0068 Cf 6.08 2.41 1.09 0218 Cf 7.17 3.35 1.15 0298 Cf 4.28 3.21 1.49 0018 2 4.67 2.13 0.94 0198 ? 0.29 0.82 0.36 0208 Y 3.46 2.35 0.85 0308 Y 10.74 6.20 2.06 X 5.68 2.83 1.104 S2 10.6417.6 9.2530 0.251 S 3.26 3.04 0.50 DEtR NO. E . Wl N L. W I N SPR 2118 # # # # 0 0.89 2038 IW 0.81EE1 0.54 2068 2128 4088 0.33 1.57 2.46 0.39 4098 4108 1.06 0 .7 7 4128 0 . 7 5 1.18 Figure 6. Periods of use and average activity radii (km) of sub- seasonal ranges occupied by radio-collared mule deer on the Brackett Creek winter range during 1978-79. 25 separate early winter and combined late winter-spring range and use of a combined early-late winter and a distinct spring range. During January and early February, mule deer activity generally centered in areas of heavier cover. This period was characterized by sub-normal temperatures, normal to above normal snowfalls and above normal snow depths. Daily movements were generally limited and associated with feeding in or adjacent to cover. A period of warming temperatures and rapid snowmelt in mid- February resulted in rapidly decreasing snow depths which allowed deer to use a larger portion of the winter range. Four of the nine radio-collared deer established new activity centers moving an average of 1.2 km to areas used thereafter as late winter-spring ranges. Another deer moved 4.8 km to a late winter range. , The three radioed deer which established separate spring ranges moved an average of 4.3 km from their previous activity center. In general, these spring ranges were located at higher elevations on the winter range than previously-used range areas and may have represented some.upward movement following "green-up". Average activity radii of radio-collared deer on late winter and spring ranges were slightly larger (Fig. 6) than those of early winter but the differences were not statistically significant (t=0.22, 13 df). One deer, 4088, which exhibited the opposite trend, seemed to make test movements to the late winter-spring range before establishing 26 that range. The mean polygon home range sizes, standard diameters, and average activity radii for eight radio-collared mule deer does on 2the Brackett Creek winter range were 12.9 km , 3.3 km and 1.4 km, respectively. Average activity radii of eight neckbanded mule deer (Table 4) on the Brackett Creek winter range during 1978-79 (X=1.10 km) did not differ significantly (P=0.40) from those of radio- collared deer. The daily and two-day movements of marked deer on the winter range are summarized in the Appendix, Tables 21 and 22, respectively. Only average activity radii were compared statistically. During early winter the mean daily AAR was 0.24 km with wide variation bet­ ween and among individuals as well as occasionally between observation periods for the same individual. Commonly, deer established somewhat repetitious patterns of use in areas adjacent to activity centers' (see Appendix, Fig. 15). Although, mean daily AAR's for early and late winter, 0.24 and 0.33 km, respectively, were not statistically different (P10.10) there was an apparent trend toward greater movement in late winter. The mean AAR's for 18 two-day and 41 one-day observation periods were 0.37 kin and 0.29 km, respectively. The differences were not statistically significant (P<0.10). That finding supported the subjective impression of repetitious use of the same local areas. 27 In winter mule deer were active during all parts of the day (see Appendix, Fig. 16). Intensively observed deer were active approximately 57 percent of the total observation time. The percent of time individual deer were active varied from 33 to 67 percent (Fig. 7, see also Appendix, Fig. 16). Individuals observed 4 or more days were active 50 to 67 percent of the total time observed. The winter home range,of the least active deer was immediately adjacent to a haystack. Its lower daytime activity may have been compensated by greater nocturnal activity. The amount of midday activity by deer was generally greatest during the mid-winter period and declined after March as weather moderated (Fig. 8, see also Appendix Fig. 16). Summer-Fall (11 May 1978 to 25 December 1979) Distribution Mule deer were distributed throughout the study area during summer. The Brackett Creek summer range encompassed an area of 24,360 ha, and primarily included that portion of the Bangtail Ridge north of an imaginary line connecting the Stone Creek-School Gulch divide.and the Bangtail Creek-Willow Creek divide and adjacent foot­ hills above 1,707 m elevation. All but three of the radio-collared deer summered within these boundaries (Fig. 9). One of those was a year-long resident on the winter range. Another spent the summer using an area which spanned the upper elevational limits of winter 28 Figure 7 Figure 8 IOOi O wCO oo