Structural characteristics and ecological relationships of male blue grouse (Dendragapus obscurus [Say]) territories in southwestern Montana by Robert Rehm Martinka A thesis submitted to the Graduate Faculty in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY in Fish and Wildlife Management Montana State University © Copyright by Robert Rehm Martinka (1970) Abstract: Structural characteristics of male blue grouse (Dendragccpus obsGurus) territories and their relationship to land-use practices and forest succession were .studied from 1967-1969 on a 700-acre area of the Sapphire Mountains in southwestern Montana. A description of the physiography and vegetation was given. The area has been selectively logged periodically since 1948. During 130 observation trips, . 1,010 sightings of males on 40 territories were made. About 60 percent of the males were leg-banded for individual identification.¦ Vegetative and physical characteristics were recorded for 27 territories where males were observed 14 or more times; Territory size averaged 1.99 acres. Thickets of-coniferous trees, which were the major vegetational component of territories, averaged .211 acres and provided about 675 feet of edge. . The density of thickets averaged about 1200 -trees per acre. Average thicket tree diameter was 4.9 inches. Most trees in thickets were from 10 to 60 years old Territory thickets composed mostly of Douglas-fir were generally of greater density and smaller total area than those composed mostly of ponderosa pine. The longevity of thickets used by males was apparently about 40 to 50 years. Territories that- were occupied intermittently during an eight-year known history averaged 2.33 acres while those occupied continuously averaged 1.79 acres. Discriminant function analysis indicated that territories could be distinguished from unused areas with a high degree of success (96 percent) when ten variables were used. As the. number of variables was reduced, the quality of the results decreased. Selective logging may be beneficial because it opens up the canopy which allows the regeneration of trees in the form of scattered thickets. Clear-cut- logging might also be beneficial if used on small blocks of timber (10 to 60 acres). - Silvicultural practices such as mistletoe control, terracing on clear-cut areas, and thinning were discouraged in multiple-use management where blue grouse breeding habitat is paramount. Breeding habitat was associated with a ponderosa pine fire successional stage in the Douglas-fir vegetational zone, or with immature climax stages in both the ponderosa pine and Douglas-fir vegetational zones. With the curtailment of uncontrolled fires, logging is probably necessary if blue grouse breeding habitat is to be maintained or created. Male territories tended to be evenly spaced which was possibly initially a result of habitat requirements and/or selection and secondarily of territorial behavior. Longevity of males did not seem to be related to habitat type.  STRUCTURAL CHARACTERISTICS AND ECOLOGICAL RELATIONSHIPS OF MALE BLUE GROUSE (.DENBRAGAPUS OBSCURUS [SAY]) TERRITORIES IN SOUTHWESTERN -MONTANA by ROBERT REHM MARTINKA A thesis submitted to the Graduate Faculty in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY in Fish and Wildlife Management HeacL Major Departmentfcm Chairman, Examinihj Committee GradudteDean MONTANA STATE UNIVERSITY Bozeman, Montana June, 1970 ACKNOWLEDGMENT To the following, among others, I wish to extend sincere appreci-r ation for their contributions to this study: Dr. Robert -L. Eng, Montana State University, for technical supervision and guidance in preparation of the manuscript; Mr. Thomas W. Mussehl, Montana -Fish and Game Department, for initial project planning, advice, and assistance; Mr. Phillip Schladweiler, Montana Fish and Game Department, for advice and assistance; Mr. L. Jack Lyon, Intermountain Forest and Range Experiment Station, for advice on statistical problems; Mr. Barry Frost for field assistance; Dr, W. E. ,Booth, Montana State University, for verification Of plant specimens; Dr. Don C. Quimby and Dr. Richard J. Graham, Montana State University, for critical reading of the manu­ script; Mr. and Mrs. Phillip E. Snider for hospitality during the field work phase; and to my wife, Kathy, for encouragement and understanding. During this study, I -was supported by the Montana Fish and. Game Department under Federal Aid Project Nos. W-91-R-10, W-9I-R-11, and iii W-91-R-12. iv TABLE OF CONTENTS VITA . . . . . . ACKNOWLEDGMENT . TABLE OF CONTENTS LIST OF TABLES•. ii. iii iv. v Page LIST OF FIGURES vi ABSTRACT .................................. viii INTRODUCTION . . ■.................. ........................ . . I DESCRIPTION OF THE STUDY AREA ............ . . . . . . . 3 METHODS ................. ■........................ .. 9 Observational Procedures . . ..... ........ . . . . . . 9 Territory Structure Analysis ................... 12 Overall Vegetational A n a l y s i s ............ 15 RESULTS . . . ........................ .. . . . . . . . . . . . 17 Territory Occupancy . . . ........ .. . ........... .. . ; 17 Vegetational Measurements . ...................... 25 Physical Characteristics . . . . . . . . . . . . . . . . 31 Discriminant Function Analysis . . . . . . . . . . . . . - 40 LAND-USE AND SUCCESSIONAL RELATIONSHIPS . . . ............. .. 42 Logging . . . ........................................ . 42 Silvicultural Practices ............... . ............. 44 Successional Relationships.............. 46 DISCUSSION 52 APPENDIX 58 LITERATURE CITED 71 V1. CANOPY COVERAGE AND FREQUENCY OF TAXA FOR THE TWO HERBACEOUS TYPES AS DETERMINED JBY EXAMINATION OF TWENTY 2. X 5 DECIMETER PLOTS ON EACH OF 16 SITES ...................... 7 2. A COMPREHENSIVE LIST OF THE FLORA PRESENT ON THE STUDY AREA .................................... 59 3. THE NUMBER OF OBSERVATIONS AND MINIMUM AGE OF INDIVIDUAL • MALES ON DIFFERENT TERRITORIES FOR 1968 AND. 1969 . . . . . 20 4. DAILY OBSERVATIONAL. DATA FOR 1968 AND 1969 . . . . . . . . . 21 5. CHARACTERISTICS OF CONIFEROUS THICKETS USED BY TERRITORIAL •MALE BLUE GROUSE . ........................................... 27 6. CHARACTERISTICS OF CONIFEROUS THICKETS NOT USED BY TERRITORIAL MALE BLUE GROUSE..................... 28 7. THICKET CHARACTERISTICS OF TERRITORIES AND NON-TERRITORIES GROUPED ACCORDING TO TREE SPECIES COMPOSITION .......... 30 8. PHYSICAL CHARACTERISTICS OF 27 MALE BLUE GROUSE TERRITORIES . . ; . . . ........ .. . . . . . ........... 33 9. DISCRIMINANT FUNCTION ANALYSES OF TERRITORIES AND NON- TERRITORIES IN WHICH FOUR COMBINATIONS OF VARIABLES WERE USED . ■.......................... 41 10. RESULTS OF THE DISCRIMINANT FUNCTION ANALYSIS IN WHICH ALL TEN VARIABLES WERE USED ' . . . . . . . -. , . . . . . 67 11. RESULTS OF THE DISCRIMINANT FUNCTION ANALYSIS IN WHICH FIVE VARIABLES WERE USED (THICKET SIZE, EDGE, TREES PER ACRE IN THREE CATEGORIES)........ ■ . . -................. 68 12. RESULTS OF THE DISCRIMINANT FUNCTION ANALYSIS IN WHICH THREE VARIABLES WERE USED (THICKET. SIZE, EDGE, AVERAGE ; D B H ) ........... .. ........................ 69 13. RESULTS OF THE DISCRIMINANT FUNCTION ANALYSIS IN WHICH TWO VARIABLES WERE USED (THICKET SIZE, EDGE) . ........... 70 LIST OF TABLES Table Page LIST OF FIGURES - Figure Page 1. The study area showing network of logging roads ........ 4 2. A view of the open slopes with heavily wooded draws . . . 5 3. Leg band combination on a blue grouse for individual identification............................ 11 4. Vegetation density board used to determine shrubby vegetation density profile ............. . . . . . . . . 14 5. The relationship between the number of observations of males and territory size . .......................... .. . 19 6. Seasonal distribution of the number of territorial male observations per hour in 1968 and 1969 . . . . . . . . . 22 ■7. Blue grouse displaying under.a ponderosa pine during rainy weather . .................................... 24 8. A thicket of ponderosa pine and Douglas-fir used by a territorial male blue grouse ........ . . . . . . . . . 26 9. Shrubby Vegetation density profile of territories and non-territories . . , . .......... .. 32 . 10. A sloping ridgeline.that is open on the south side and heavily wooded on the north side which was often used by a territorial male blue g r o u s e ............................. 36 11. The location of territories with respect to coniferous vegetation on the study a r e a .......................... 38 12. The composition of territories and non-territories with respect to the relative occurrence of three vegetative classes: open, shrub, and thicket .......... . . . . . 39 13. Terracing on a clear-cut area in the Douglas-fir vegetational zone near the study area . . . . . ........ 43 14. A Douglas-fir thicket destroyed in a dwarfmistletoe control program. It was once used by a territorial male blue grouse . ......... ......................."............... 45 vi vii LIST OF FIGURES . (continued) Figure Page 15. A photo sequence of forest succession over a 40-year period following logging. The photos were taken in 1909 (A) , 1927 (B), 1938 (C) , and 1948 (D) (Courtesy U. S'. Forest Service) ............ ........................... 48 16. A photo sequence showing the growth of a ponderosa pine thicket over a 20-year period. The photos were taken in 1938 (A) and 1958 (B) (Courtesy U. S. Forest Service) . . 50 viii ABSTRACT Structural characteristics of male blue grouse (Dendragccpus obsGurus) territories and their relationship to land-use practices and ,forest succession were .studied from 1967-1969 on a 700-acre area of the Sapphire Mountains in southwestern Montana. A description of the physiography and vegetation was given. The area has been selec­ tively logged periodically since 1948. During 130 observation trips, . 1,010 sightings of-males on 40 territories.were made. About 60 per­ cent of the males were leg-banded for individual identification.■ Vegetative arid physical characteristics were recorded for 27 terri­ tories where males were observed 14 or more times; Territory size averaged 1.99 acres. Thickets of-coniferous trees, which were the major vegetational component of territories, averaged .211 acres and. provided about 675 feet of edge. . The density of-thickets averaged about 1200 -trees per acre. Average thicket tree diameter was 4.9 inches. Most trees in thickets were from 10 to 60 years old/ Terri­ tory thickets composed mostly of Douglas-fir were generally of.greater - density and smaller total area than those composed mostly of ponderosa pine.. The longevity of thickets used by males was apparently about • 40 to 50 years. Territories that- were occupied intermittently during an eight-year known.history averaged 2.33 acres while those occupied continuously averaged 1.79 acres. Discriminant function analysis indicated that territories could be distinguished from unused areas with a high degree of success (96 percent) when ten variables were used.- As the. number of variables was reduced, the quality of the re­ sults decreased. Selective logging may be beneficial because it opens up the canopy which allows the regeneration of trees in the form.of scattered thickets. Clear-cut, logging might also be beneficial if used on small blocks ..of timber (10 to 60 acres). - Silvicultural practices such as mistletoe control, terracing on clear-cut areas, and thinning were discouraged -in multiple-use management where blue grouse breeding habitat is paramount. • Breeding habitat was associ­ ated with a ponderosa pine fire successional stage in the Douglas-fir vegetational zone, or with immature climax stages in both the ponderosa pine and Douglas-fir vegetational zones. With the curtailment of uncontrolled fires, logging is probably necessary if blue grouse breeding habitat is to be maintained or created. Male territories tended to be evenly spaced which was possibly initially a result of habitat requirements and/or selection and secondarily of territorial behavior. Longevity of males did not seem to be related to habitat type. INTRODUCTION Most blue gtouse CDendragetpus obsaurus) populations exhibit -a seasonal, altitudinal migration. 1 After,spending fall and winter in coniferous forests .on the higher mountain 'ridges, the males migrate in late March and early April.to relatively open forests in lower mountain areas where they establish and defend breeding territories. Females arrive shortly after, the males and nest in the same general- areas (Bendell and Elliott,1967). Structural characteristics of the vegetation found at male blue grouse territories have- been discussed by several authors ; however, no one has described them in a quantitative manner. Bendell and Elliott (1966 and 1967) noted that the position of•territories in dense cover may depend on the location of:openings, and other authors. (Blackford 1958 and Mussehl 1962) have described territories in open areas,as being associated with thickets of coniferous Vegetation. Fotest succession^ following fire or logging activities, undoubtedly acts as a.control on the density and positioning of territories (Bendell and Elliott 1966; Mussehl -1962). Breeding blue grouse accept a variety of different forest types, from moist forests in the Pacific Northwest to relatively dry forests of the-interior-Rocky Mountain region. -2- Personnel of the Montana Fish and Game Department have been con­ ducting blue grouse population and pesticide studies•(MussehI and Finley 1967) since 1962 on a small area of the Sapphire Mountains in southwestern Montana. - This area was chosen for a quantitative study of.the vegetational characteristics of male blue ,grouse territories because of the known history of approximately 40.different territories. Also, a large proportion of the territorial males had been leg-banded for individual identification.,• Objectives of.the study werd to deter­ mine the structural makeup of male breeding territories and to evaluate, the effects of forest succession in relation to silvicultural practices on blue grouse breeding habitat in ponderosa pine, (P-inus 'fonderosa), and Douglas-fir (Tseudptsuga menz-Iesii) vegetation zones. Full time field studies were conducted from late July to.late August, 19.67, from mid-April to .mid-September, 1968, and from early April,to early September, 1969. Approximately 130 trips to the study area were made for the purpose of .locating male grouse, and about'200 were made for the, purpose of vegetation analysis'. DESCRIPTION OF THE-STUDY AREA The study area (Figure I), located-10 miles southeast of Hamilton, Montana, contains about 700 acres of Bitterroot National Forest land near Skalkaho Creek. According to Perry (1962), this area is composed of granitic rock of the late Cretaceous to early Tertiary periods. Elevations range from approximately 4550. to 5750 feet mean sea level. Steep, open, south-facing, slopes intermingled with heavily wooded draws characterize the area (Figure 2). Numerous logging roads tra­ verse the hillsides providing excellent accessibility. • Logging was begun in 1947 and has continued until the present. Climatological data for Hamilton (elevation 3529 feet) show a mean annual temperature of 46.1 F. . January is the coldest month and July is. the warmest with average temperatures of 24.1 F and .67.9 F, respectively. Average annual precipitation is 12.74 inches. The only months with average precipitation exceeding 1.20 inches are May and June which average 1.67 and 2.04 inches, respectively. Because pre­ cipitation generally increases with elevation ;.in this region, the study area undoubtedly receives more moisture than Hamilton. On April I, 1969, portions of the study area had 18 inches of snow remaining on the ground while Hamilton had none. In addition to the influence of logging operations on the area, heavy summer grazing pressure was exerted by domestic livestock, mum Study A n a Figure I. Map of the study area showing network of logging roads. Figure 2. A view of the open slopes with heavily wooded draws. —6— particularly on creek.bottoms and other moist sites. Mule deer (Odocoileus hemtonus) and elk (Cervus canadensis)- use the open, south­ facing slopes as winter range. The study area included portions of both the ponderosa pine and Douglas-fir zones as described by Daubenmire (1953). Semi-open stands of ponderosa,pine dominated the lower elevations while stands of pine with Douglas-fir interspersed were found at higher elevations.' The heavily wooded draws consisted mostly of Douglas-fir. The pine has been selectively cut on much of the area and is apparently being re­ placed by Douglas-fir at the higher elevations.. Average crown.cover of the study area as. determined from aerial photographs was about 30 percent. The unforested portions of the area consisted of three different ' vegetation types,. Two herbaceous ' types -were -..dominant while a shrubby type was of minor importance. . Canopy coverage and frequency of occur­ rence of the principal plant species present in the two herbaceous types are presented i n ;TabIe I. The dryer portions of the.area supported a bunchgrass vegetation type in.which, bluebunch wheatgrass, (Agropyron spicatum) , Junegrass (Keeleria cvistata), and Idaho, fescue ('Festuca idahoensis) were the major grasses and arrowleaf bals.amroot (Balsamovhiza sagittata) , silky lupine (Lupinus sevieeus) , yarrow (Achillea millefolium) , and field . chickweed (Cevastium av.vense) were the major forbs. -7- TABLE I. CANOPY -COVERAGE AND. FREQUENCY OF TAXA FOR THE TWO HERBACEOUS TYPES AS DETERMINED BY EXAMINATION OF TWENTY 2 -X 5 DECIMETER PLOTS ON EACH OF 16 SITES. Taxai-/ • Vegetation Type' Bunchgrass (10 sites) Pinegrass (6 sites) Coverage GRASS AND GRASS-LIKE PLANTS 13 Frequency- 100 Coverage 35 Frequency 100 Agropyron spieatim- 3.0 46 y2J X Bromus teotorum 1.4 ' 35 X X Calamagrostis purpuresoens X X ■ 1,6 19 - Calamagrostis rubesoens X X 25.0 92 • Caress- geyeri X X 5,0 50 Festuoa -idahoensis, 2.6 31; 0.8 16 Koeleria -oristata 3.3 . 58 ' - - Poa spp. 1,4 52 3.9 33 ' FORBS 16 99 ■ 19 100 Achillea millefolium. 1.-7 ■ 53 1.4 49 Anaphalis margaritaoea- - - 0.3 12 Antennaria raoemosa - — 0.9 10 Arenaria oongesta ■ 0.4 14 - - Arnioa oordifolia - - 1.5 43 Balsamorhiza sagittata 8.0 48 X X Cerastium arvense - 1.2 36 X X Erigeron spp, Frdgarid-.virginiana ■ 0.6 12 - - : X, X . 5.6 5,S Gayophytum -nuttallii 0.7 27 X X Lupinus serioeus 2,4 25 8 . 2 - 51 Sedum stenopetalum. X X - 0.5 14 Silene nootiflora — - 0.8 15 ' Taraxioum officinale X X 0.5 10 Tragapogon dubiUs . 0.4 15, X • X Unidentified forbs 0.-8 25 X X SHRUBS• Symphorioarpus albus ■ 0.7 ' 10 - - I/ Includes taxa with at least 10 percent frequency of ,occurrence or one percent canopy coverage in at least one,vegetation type. 2/ Indicates taxon' present but less than 10 percent frequency .of occur­ rence or one percent canopy ' coverage; -8- The more moist portions of the area supported a pinegrass (Calcmagvostis vubesaens) .vegetation type:in which scattered pine and Douglas-fir were usually present.- Pinegrass, elk sedge (Cavex geyevi) , and blue grass■(Poa spp.j were the major grasses and grass-like species, and silky lupine-,- Virginia. strawberry -(Fvagavia vivginiccna) , yarrow, and ' heart-leafed arnica (Avnioa oovdifolia) were, the major fprbs-. A shrub vegetation-type .occurred on some,of the more, moist sites and in creek bottoms.. The major shrub species present were.common snowberry (Symphovioavpus albus)., ninebark (Physooavpus malvaoeous) , mockorange (Phiiadelphis .lewisii)chokecherry -(Pvunus vivginiano.) , white ,spiraea (Spivaeaibetulifolia)i and red dogwood (Covnus-,stolonifeva). A comprehensive listing of the plants, occurring on the study area, is presented- in Table -2 in • the . appendix. Plant-nomenclature is ,accord­ ing to Booth (1950) and Booth and Wright (1966). METHODS- ) Each year field work was divided . into two maj or .phases.. From April through mid-June,-, a concerted effort was made to locate terri­ torial males, and plot ,their locations on aerial photographs.. Mid-June to September was devoted to vegetation measurements., The severe decline in male breeding activity by mid-rjune created a natural divi-. sion for the-two phases; 'Observational Procedures A 4-wheel drive vehicle was used to travel an 8.8- mile - route through the study area while conducting morning and evening obser­ vations, Morning observations were of three to four.hours duration beginning about one-half hour- before sunrise. Evening observations were begun about three hours before sunset and continued until visibility :was ' impaired,. These, periods ,coincided with times of greatest,breeding activity (Blackford 1963; Wing 1946; and Bendell 1954). During the-seasonal breeding peak, the large number of obser­ vations prevented covering the entire area during a single morning or. evening activity period. Some observations were made on foot.. Obser­ vations from vehicles were probably more indicative of normal-.behavior because many males.were more disturbed by persons on foot.than they- were of vehicles. —10— An attempt;was made to capture and band all territorial males. They were captured with :a plastic-covered wire noose.attached, to the end of a,24-foot telescoping -fiberglass pole (Zwickel-.and Bendell 1967). , Birds, were marked .for.individual field identification with a combination .of numbered, plastic and .aluminum bands of various'colors (Figure 3)„ Different color combinations were used each, year. ■ When a banded territorial male,was sighted, a 15x-60x spotting scope or a 7X50 binocular aided in.checking the band number and/or color.-. If the bird was-wary or too far away-, a recorded female call. (Stirling and Bendell 1966) was used to coax - it. closer. The ca]Ll was also useful in locating males that were not readily observable. At least some gave multiple hoots in response- or came out in the open. Each male observation was plotted on colored aerial photographs taken during a low level flight in 1967. Territorial boundaries were then delimited from-the.plotted observation -points. . The projected size of.a territory varies with the number of observations until,a point is reached where more,observations will : not add greatly to the size (Odum and Kuenzler, 1955) . In order to determine this approximate point, the number of observations- of each male was plotted against the size of its territory. Once this point was determinedj emphasis could be placed on locating males which had been observed less than the desired number of times. —11— Figure 3. Leg band combination on a blue grouse for individual identi­ fication. -'12- Territory Structure Analysis Overall territory size was■determined;from-aerial photos -by measuring all the area included in boundaries formed by connecting the outermost observation points. To reduce• .the' error in acreage determi-r■ nation caused by. radial distortion in the photos, territorial boundaries were transferred to a sheet of paper using a method described by Meyer, et al. (1970). Area.was then determined by using a dot grid. Most other measurements were made in the field with emphasis placesd upon , coniferous thickets in the t e r r i t o r i e s A thicket was defined as an area having a density:of 300 or more trees per acre. • Among the variables measured were the number.and total-size of thicket(s) in use, tree species, composition of thickets, average -age of oldest treesj and the amount of edge formed by the perimeter of thickets and open areas. Tree age was determined with the use of an increment borer, and other quantitative measurements were made, with the use of a 100-foot steel tape. . Crown cover of each of the terri­ tories was determined from aerial photographs using a.dot grid. • All ■ trees .,in the thickets, were measured, with a diameter tape and placed in diameter categories of 1—3, 4-8, and.greater than 8 inches. From these.data, the.number-of -trees per.acre in each diameter category was determined. Wherei thickets were too large for.all trees to be. measured, ten randomly-placed one-hundreth acre plots were used. Also measured -was the height,to the lowest live-branches under. 10 feet high.. -13— The percent slope was.measured with an Abney, level, exposure was determined with a-compass, and the average altitude with an altimeter. Other characteristics that were.recorded were the amount -of shrub cover, and the distance from the center of one territory to the center of the nearest neighbor territory.. The- activity center rather than the geo­ metric.center was■ used in determining this distance. A vegetation density profile of each territory was determined using a technique modified from that proposed by Wight (1938), By this method, a board.6 feet in length with each foot marked off and numbered from one, to six was - ,used. The board was placed upright in the approximate center of the territory, and an observer standing 50 feet from it esti­ mated and recorded, the amount, of cover. obstruction at. each one-foot:- interval (Figure 4). Estimations of obstruction were made -in,categories ■ of 0-5, 5-25, 25-50, 50-75, 75-95, and 95-100 percent, An average per­ cent obstruction for each one foot interval was - obtained by adding the, midpoints of all obstruction estimates for that interval and dividing by,the number of observations. Eight readings were made in each terri­ tory, one at each, of eight,major compass directions. To permit•a-statistical analysis = of the vegetational.character­ istics, a series of measurements-similar to those,described above were made on ,an equal number of areas .designated as "non-territories". They were selected at random-from portions of .the study area.that had coni-. ferous vegetation present but no history of use-by territorial male — 14- Figure 4. Vegetation density board used to determine shrubby vege­ tation density profile. -15- bltie groUse. . Discriminant function analysis (Snedecor and Cochran 1967) was used to determine if measurable differences existed between areas selected by male grouse for territories and areas not-used by.males. The variables which showed no significance in. the.analysis were eliminated and, the.remaining judged the most significant territorial characteristics. In this method,, all of the vegetation measurement data are used to formulate an equation,.the discriminant function. The data from each territory.and non-territory.are then inserted into this equation separately. The - magnitude of.the resulting figure indicates whether• the variables and interaction between variables for the particular area are more closely related to those,determined overall for the terri­ tories, or those determined overall,for the non-territories. Thus the area, whether it is actually a territory or a non-territory, is classi­ fied as one or the other through the use of the discriminant .function. The probability that the area was classified correctly was also deter­ mined . Overall'Vegetational Analysis' Vegetational measurements in-the open areas were made with a. modification of the method described by Daubenmire; (1959). Canopy coverage and - frequency, of occurrence of grasses, forbs, and.shrubs were determined with the use of twenty.2 X 15 decimeter plots placed at -IS-- 10 foot intervals along- each of 16 paced.transects through representa­ tive sites. The-percent canopy coverage of each species, and percent­ ages of.bare ground -and rock were recorded for each plot.. Percentage classes were the same as those ., used in the vegetation density profile readings and.the midpoint-of each class was the value used in data tabulations RESULTS Territory Occupancy Observations of banded male blue grouse indicate that some may be present on territories as early as the last week it March. Others may not be situated on a territory until the second or third week in April even though they have been present in the general area since the beginning of that.month.• Initiation of breeding behavior occurred during the first week in April. Forty-three territories have been occupied on the study area at one time or another since 1962 as indicated by the present and previous studies (Schladweiler. and Mussehl 1968). In ,the springs of ,1968 and 1969, 39 and 40, respectively, of these territories were occupied. . At ■ least two territorial males were killed by predators in 1968 and four. in 1969. In a minimum of three of these cases, other males took up occupancy after variable periods of time. A total of 1,010 sightings of individual adult male blue grouse was made. The number of sightings per male over the two-year period ranged from I to 72; All sightings were plotted on aerial photographs. The number of- plotted, observations of a given male may be greater than the number of individual sightings due to extensive movement during a single, sighting. A comparison of the number of observations of a male and the size of its territory indicates that the territory size increased with the —18- number of observations until a male was observed about 14 times (Figure 5). Therefore, fourteen observations of.an individual,male were.con-, sidered sufficient to indicate the approximate size and extent of a, territory .■ Measurements of vegetational characteristics were • limited ' to the,27 territories where males had been observed 14 or more times, The number of observations and minimum age of males on these territories is presented in Table 3. In 1968, 58 percent of 36 and in 1969, 70 percent of 36 territorial males closely observed were banded. For the years 1968 ahd 1969 > 81 and 68 percent, respectively, of the males having bands the previous year returned to their respective territories. Over the two-year period, . the return rate averaged 74 percent• Two males banded in 1962 were still occupying the same territories in 1969. One disappeared later that- spring. Ten adult and seven yearling males were banded during this study. Results of the daily observational periods,are presented,in Table 4. There was an indicated difference between 1968 and-1969.in the peak of breeding activity, based on the number, of■adult-male observations per hour (Figure 6). The-data from,1969 compare more favorably-with other studies than those from 1968. The number of female sightings per hour., - which, also may be indicative of the relative degree of breeding activ­ ity, generally supports the data on males pertaining to activity peaks. About .11 percent of the male observations were made on foot rather-than Te rri to ry Si ze (a cr es ) Number of Observations Figure 5. The relationship between the number of observations of males and territory size. -20-. TABLE 3. THE NUMBER OF OBSERVATIONS AND MINIMUM AGE OF INDIVIDUAL MALES ON DIFFERENT TERRITORIES FOR 1968 and 1969. Territory No. Min. Age of Male • (1969) Number of Observations 1968 . 1969 Total 10 3 A 5 22 43 65 104 5 5 23 28 105 4 9 ■ 30 39 42 unk.-lA 4 16(NB)2/ 20 32A 8 7 27 34 32B uhk. ■ 4 16(NB) 20 30 3 3 14 17 30A 5 20 52 , 72 65 9 11 (21)1/ 32 73A . 2 7 (21) 28 54 9 9 19 28 • 94 4 9 23 32 94A 8 7 21 28 62 unk. ' 12 14(NB) 26 38 2 15 ( 2 3 ) 38 38A 2 12 27(NB) 39 72 2 19 (2 9 ) 48 27 unk. 6 - 16(NB) 22 47 3 . 3 19 22 ■ 48 unk. 13 30(NB) 43 ■ 51 unk. 6 (1 6 ) 22 53 4 22 31 53 52 2 7 (2 4 ) 31 82 ’ 2 6 (2 3 ) 29 115 I 2 ■ 12 15(NB) 27 116 unk. 10 IS(NB) 28 78 unk. 20 (3 3 ) 53 I/ Age unknown . 2] Indicates that the male was not banded in 1968 so individual identification was'not permitted for both years. _3/ Parentheses indicates that the territory was occupied by different males in.1968 and 1969. . TABLE 4.. DAILY OBSERVATIONAL DATA FOR 1968 and 1969. Period. Adult' Males■ Others Total Hours of Search Miles of Search Males/ Hour Birds/ Hour 1968 4—14 4 2 6 2 . 5 10.5 1.60 2.40 4-19 to 4-22 47 11 58 . 26.5 7 2 . 2 1.77 2,19 4—27 to 4—30 58 13 71 25.3 73.4 2 . 3 0 2.81 5— 3 to 5— 6 59 19 78 20.5 47.0 2 . 8 8 3.80 5-10 to 5-13 73 33 106 24.6 78.9 2.96 4.30 5-16 to 5-19 50 18 68 15.4 4 8 . 4 3 . 1 8 4.35 5-25 to 6-13 21. . 8 29 16.3 89.1 1.29 1.78 Sub-totals 312 104 416 131.1 419.5 2.38 3.17 1969 3-29 to 5— 3 36 18 54 23.3 8 4 . 9 1.54 1.97 ^ 4— 6 to 4—12 127 72 199 40.4 167.2 3.14 4 . 9 3 Y 4-17 to 4-19 52 • 36 88 15.2 72.2 3.41 5.77 4—20 to 4—26 140 84 224 38.1 167.0 3 . 6 8 5.88 4-27 to 5- 3 111 51 162 25.4 118.2 4.37 6 . 3 8 5- 4 to 5- 9 146 78 224 30.1 136.1 4.85 7.45 5-12 to 5-16 65 36 101 21.1 1 1 8 . 3 3.09 4.80 5-25 to 5-29 21 6 27 8.5 57.6 2.47 3.18 Sub-totals 698 381 1079 202.1 921.5 3.45 5.34 Totals 1010 485 1495 3 3 3 .2 1341.0; 3.03 4.49 ? 2.5 28 1 DATE Figure 6. Seasonal distribution of the number of territorial male observations per hour in 1968 and 1969. -'23— - from a vehicle but have been included in the total. Approximately 1.33 miles were driven for each adult male sighted and 0.90 for each blue grouse sighted. This latter figure is consid­ erably better than the one grouse per 26.07 miles of travel recorded by Rodgers (1968) over a three-year period in Colorado. Bendell and Elliott (1967) recorded a high of .81 hooting males per hour of foot search during the peak of breeding activity (May I to 14) on Vancouver Island. During the present study, as many as 4.85 males per hour of vehicle search were recorded. Although differences in physiography and habitat types between the areas are considerable, the densities of territorial males were similar. Thus; it appears that search by vehicle, when feasible, may be more efficient than search on foot. About'68 percent of all blue grouse observed were adult males. The high percentage of birds in .this category is attributed to the fact that adult males are much more conspicuous, especially when displaying, than are females or yearling males. Also, the observer probably biased these results by concentrating the search mostly to known,territories, where females and yearling males would not necessarily be.found. Eighty-six percent of the adult males observed were either "hooting" or displaying. Of these, 88 percent were in open areas. During rainy or windy weather, males were most often observed hooting in thickets or under trees (Figure 7). Twenty-eight percent of the males observed hooting in the open were on roads. These figures are undoubtedly -24- Figure 7. Blue grouse displaying under a ponderosa pine during rainy weather. -25- inf luenced .by observational bias, but they probably reflect somewhat the tendency of males to. display in!open areas, particularly on roads (when available), where visibility is least restricted. Vegetation Measurements Thickets of coniferous .trees which were probably used for resting and escape cover appeared to :be a major vegetational.component of each male blue grouse territory ■ (Figure 8). Therefore, various measurements were made on the thickets and the trees of which they were comprised (Table 5). Similar measurements were made on 27 randomly selected areas designated as non-territories which corresponded in size to the terri­ tories (Table 6). The least variable of all vegetational characteristics measured was the amount of edge provided by. the thicket(s). The territories con­ tained an average .of .211 acres of thicket and an average of 677 feet of, edge. Numerous, small thickets often provided, as much edge as one large one. For example. Territory 52 contained six thickets, totaling .089 acres with .577 feet of edge, while Territory '105 had one thicket totaling .294 acres but only 570 feet of edge. In the non-territories, an average of .055 acres of thicket provided-an average of 278 feet of edge, both of which were significantly different.(p<.01) from the. territories. -2 6 - Figure 8. A thicket of ponderosa pine and Douglas-fIr used by a territorial male blue grouse. TABLE 5. CHARACTERISTICS OF CONIFEROUS THICKETS USED BY TERRITORIAL MALE-BLUE GROUSE. Terr. No. Terr. Size^ Thicket Area^/ Thicket Edge?./ Trees Ave. Branch DBH^/ Ht.-/ ■m>A/■ %DF— All- Trees ■1-3" per Acre 4-8" > 8" 10 3 A 1.60 .254 599 5.4 4.9 93 ' 7 1074 241 574 259 104 2.44 .366 897 8.7 5.3 88 12 434 46 153 235 105 1.14 .294 570 5.5 5.3 98 2 1123 395 633 95 42 ' 1.82 .402 874 4.6 5.9 67 33 309 127 162 20 32A 1.42 .187 576 . 5.1 5.8 52 48 471 176 225 70 32B 2.26 .313 608 4.5. 4.4 31 69 361 176 166 19 30 3.60 .152 573 4.7 5.4 17 83 1092 375 592 „ 125 30A 2.16 .174 581 4.6 5.6 53 47 1288 437 730 121 65 • 1.58 .256 580 3.9 6.0 87 13 790 340 438 12 73A 2.61 .189 850 5.7 5.5 24 76 937 217 540 180 54 1.30 .148 584 4.0 4.6 2 98 1628 824. 750 54 94 2.10 .156 665 3.7 4.4 4 96 1923 1064 ' 814 45 94A 2.24 .174 697 4.4 5.0 5 95 1339 494 759 86 62 1.86 .235 787 2.7 5.1 8 92 1803 1244 513 46 38 1.60 .211 520 3.3 ' 5.3 4 96 1341 744 597 0 38A 2.12 .276 795 4.3 5.3 9 91 1210 533' ..583 . 94 72 1.74 .197 697 3.7 5.3 I 99 1955 919 985 51 27 2.11 .123 625 4.6 4.5 9 91 1235 463 707 65 47 1.96 .143 660 4.9 4.8 11 89 1594 524. 986 84 48 1.74 .196 598 5.2 5.0 10 90 918 291 490 138 . 51 1.29 .158 770 4.8 5.7 15 85 2323 842 1354 127 53 1.63 .208 923 4.2 6.7 18 82 1800 790 989 77 52 1.56 .089 577 6.5 6.3 99 I 1663 371 955 337 82 2.82 .117 614 9.3 6.3 100 0 778 60 410 308 115 2.27 .248 825 3.7 6.0 31 69 1298 802 468 28 116 2.43 .255 617 3.7 5.2 90 10 1263 710 510 43 78 2.22 .177 625 5.6 5.3 53 47 610 175 328 107 Average 1.99 .211 677 4.9 5.4 40 60 1205 496 608 105 JL/ Territory size and thicket area are in acresi If Edge and Branch. BeigTit1 are in feet ^ Zf DBH is in inches. 4/ Ponderosa pine. 5/ Douglas-fir. TABLE 6. CHARACTERISTICS OF CONIFEROUS THICKETS NOT USED BT TERRITORIAL MALE- BLUE GROUSE.- Non-terr. No. Size^ Thicket Area^ Thicket V d g J J Trees %PP-/ %DF—/ Trees per AcreAve. DBH^/ Branch Ht.-/ All 1-39 4-8" > 8". 103A 1.60 .092 487 11.9 5.5 89 11 457 0 185 272 104 2.44 .052 266 5.8 7.5 89 11 635 19 481 135 105 1.14 .082 397 2.1 1.0 26 74 1549 1463 85 0 42 1.82 .039 350 3.4 4.2 0 100 2744 1641 1051 51 ' 32A 1.42 .104 380 7,2 4.5 10 90 625 125 308 192 32B 2.26 .015 150 6.7 5.8 100 0 1000 67 800 133 30 3.60 .000 • 0 0.0 0.0 0 0 0 0 0 0 30A 2.16 .090 303 6.5 7.6 .66 34 389 78 256 56 65 1.58 .039 240 7.1 5.8 98 2 1026 179 590 256 73A 2.61 .014 100 12.0 8.9 100 0 857 0 286 571 54 1.30 .032 220 9.6 5.5 100 0 ' 688 0 250 438 . 94 2.10 .007 128 6.3 8.3 6 94 2430 290 1430 ■ 710 94A 2.24 .140 647 5.7 6.4 12 88 843 286 379 179 62 1.86 .048 354 4.0 6.1 54 46 1979 979 896 104 38 1.60 .020 158 8.7 5.6 82 18 850 0 500 350 38A 2.12 .012 100 . 5.3 6.0 100 0 1500 417 1000 83 72 1.74 .034 249 8.0 5.6 50 50 765 88 412 265 27 2.11 .076 372 8.2 4.9 46 54 947 132 395 '421. 47 1.96 .029 126 6.2 4.7 0 100 897 276 414 207 48 1.74 .299 730 6.0 5.3 26 74 690 140 345 205 51 1.29 .067 390 8.9 7.0 62 38 821 119 298 403 53 1.63 .065 188 9.9 8.0 89 11 292 15 92 185 52 1.56 .020 210 10.0 7.9 50 50 1250 100 250 900 82 2.82 .024 • 200 2.8 1.2 0 100 1667 1250 417 0 115 2.27 .037 240 6.7 10.0 26 74 1243 865 162 216 116 2.43 .055 220 5.4 5.4 5 95 1018 382 582 55 78 2.22 .065 298 5.9 4.4 97 3 1215 323 585 308 Average 1.99 .055 278 6.68 . 5.67 51 49 1051 342 461 248 If Non-^territory size and thicket area are in acres ^ 2/ Edge and Branch height-are In feet. 37 DBH is in inches. 4/ Ponderosa pine. 5/ Douglas-fir. -29-- The average DBH (diameter: breast- high) of trees ill - the territory thickets was 4,9 inches which is significantly less (pc.Ol) than the 6.7 inch average occurring in the non-territory thickets, and the aver­ age number of trees per, acre over 8 inches DBH was significantly less (p<.01) in the territory.than in-the, non-territory'thickets (105 trees per acre vs.. 248 trees per acre),. Thus, the males used thickets that were generally younger than those in non-territories. Ages of the majority of trees contained in the territory thickets ranged from about 10 to 60 years with most of them in the 20 to 40 year range. Thickets with most trees younger than 10 or older than 60 years were seldom.used except-when they were of a growth form that provided protection without obscuring vision* :■ The species composition of thicket trees varied considerably with an.increase in Douglas-fir as the elevation increased. There was no significant difference, in species composition or overall densities of thicket trees between territories and non-territories. - The territories and non-territories were separated into three categories based on the species composition of■thicket trees. The- ponderosa pine type had thickets containing more than 75 percent pine, the Douglas—fir type.had thickets, containing more than 75 percent fir, and the mixed type had thickets in.which neither species made up more, than 75 percent of the total. A comparison of the results (Table 7) indicates that the Douglas-fir type :territories contained less thicket -30- TABLE 7c THICKET CHARACTERISTICS 0F TERRITORIES AND NON-TERRITORIES GROUPED ACCORDING TO TREE SPECIES COMPOSITION.' Terr. Thicket Ave. . Edge!/' DBid/ Branch Ht.i/ Trees per Acre Type Size=/" Area=.' ■ All 1-3" 4-8" >8" Territories • Ponderosa Pine(7)— ' 1.94 .233 636 6,1 5.6 1018 309 525 184 Mixed(6) . 2.03 .250 681 4.7 5.5 723 315 • 347 61 Douglas- fir(14) 1.99 .183 696 4.3 5.2 Non-territories..., 1507 666 761 84 Ponderosa Pine(IO) 1.94 .041 221 8.3 6.3 852 102 442 286 Mixed(9) 1.76 .084 361 6.7 6,2 1070 440 344 286 Douglas-: fir(Bi 2.11 .057 293 5.3 5.0 1460 607 £54 199 JL/ The number of territories or non-territories in each group/' 7J Territory, size and thicket area are in. acres,. J3/ Edge and branch height -are in feet. 4/ ,Average DBH is in inches. araa than the other types, The greater tree density in these thickets could make them more secure and account for the smaller area. These higher densities could be due to the relative shade tolerance of Douglas- fir and the younger age of the thickets. The ponderosa pine thickets were less dense and contained, on the average, larger, trees. The rela­ tive intolerance of pine to shade and the lack of young pine thickets in the area could account for this. The open areas.of territories contained mostly,herbaceous vege­ tation with occasional areas of shrubby cover. The density profile of — 31— the .shrubby vegetation on territories and non-territories is presented in Figure 9. Since the growth of herbaceous vegetation occurs largely after the peak of grouse breeding activity, only the profile of the shrubby vegetation was determined. There is an indicated increase in the shrubby vegetation density in.the territories from the ground level upward while the opposite is apparent in the non-territories. This difference is due to both :the amount of shrub cover and its growth form. Only ten of the territories had significant amounts of shrub cover while 13 of the non-territories had significant amounts. In the 10 territories and .13 non-territories^ shrub cover.averaged.1400 and 6300 square feet, respectively. Small.amounts of shrub cover may bemused.for escape and resting cover■as indicated by Bendell and Elliott (1967); however, large amounts, probably cause too much vision obstruction and are thus avoided. . Large, mature ponderosa pine and/or Douglag-fir trees were present in most,of the territories, but their presence is probably not necessary for territory occupancy. They were occasionally used for escape cover since the birds often flew into, them when flushed; Bendell and Elliott (1967) noted that no large trees were present on the breeding areas they studied on,Vancouver Island. Physical Characteristics Various physical characteristics of the 27 territories are recorded in Table .8. Overall territory■size was included in Table 5. Territories Non-territories He i i k t H k i v e 6 r m l ( f e e t ) Figure 9. Shrubby vegetation density profile of territories and non-territories. -33- . TABLE 8. PHYSICAL CHARACTERISTICS 0F 27 MALE BLUE GROUSE TERRITORIES. Terr. No. . Altitude■ %Slope % Crown. Cover No. of Thickets Distance to NeighboriL/ Exposure 10 3A 5420 18-35 18. 4 460 NE,SW 104 5430 72 25 4 395 E-SE 105 5380 35-65 23 I 525 NE, SW 42 5400 65 19 3 395 SE 32A 5380 58 21 . 4 395 SE 32B 5460 65 27 2 525 S-E- 30 5470 23-47 43 5 395 SE-SW 30A 5510. 23-54 ' 3i 3 395 E-SW 65 5430 . 62 39 2 395 E 73A 5610 13-25 31 6 660 N,S 54 5490 57 29 4 460 W 94 5510 45-66 34 4 4 6 0 SW-NW 94A 5470 34-44• 32 ■ 4 660 W-N ' 62 ' 5400 .44 32 4 460 E 38 5380 48 34 2 330 W 38A 5400 58 29 3 330 . SW-NW 72 5410 5 8 28 5 • 525 W-NW 27 5120 27 25 , 5 • ■ 810 SW 47 5000 65 26 6 ■ 595 W 48 4950 39-56 26 2 395 SW-NW 51 4910 . 60 65 5 ' 460 NW ■ 53 4820 59 ■ 37 9 460 NW 52 4670 56 30 6 725 W 82 4620 57 31 4 660 SW ’ 115 4680 0-60 24 5 330 W,E 116 4650 20-34 23 4 330 SE-NW 78 • 4960 70 ! 33 4 395 W Average 46 . 30 4.1 478 -34- Territory size ranged from 1.14 to 3.60 acres, but only one.terri­ tory was larger than 2.82 acres. The average size was'1.99 acres which - is slightly larger than the size determined by Bendell and Elliott (1967) who worked with several different population densities. From their studies, they concluded that territory size varies inversely with population density. No such conclusion could be drawn from this study ■ since male density remained stable. There appeared to be some relationship between the age of a male and the size of its territory, Nine territories that had been,occupied by the same males for a maximum of two years averaged 2.25 acres, while ten territories that had been occupied by the same males for more.than two years averaged 1.76 acres., but this difference was not statistically significant. The altitudes of the territories ranged from 4620 feet to 5510 feet; however, territories are known to.occur at considerably higher elevations in other nearby areas. Slppes -of the territories located on ridge lines were relatively level, but most of the territories had rather steep slopes because of the general aspect -of the terrain. Tree crown cover on the territories averaged 30 percent•which is the same crown cover.figure arrived at for the entire study area. Mussehl (1962) reported that the average crown cover was 41 percent on. 12 blue grouse territories in the Judith Mountains of Central Montana, -35- Exposure of the territories included all compass directions J how­ ever, the majority faced south or west. Several of the territories were located on ridgelines extending in northwest to southeast or west • to east.directions so,that they contained portions of the heavily wooded north or northeast side of the ridge and the open, treeless, south or southwest side (Figure 10) « In such, territories, the.males often iised the ridgeline for displaying. The, distance from the center of one territory to the center of the nearest neighbor territory was measured on the aerial photographs (Table 8). In order to evaluate the significance of this spacing, the distance- to-the-nearest-neighbor method of Clark and Evans (1954) was used. This involves the calculation of a.R value which is indicative,of the degree to which the pattern,of distribution deviates from random.expectation. . R ranges in value from 0 for maximum clumping to 2.1491 for an evenly spaced distribution. An R value of I represents a random distribution. The calculated R value, determined by dividing the average distance between territories by a figure derived from the territorial male density on the area, was 1.32. This is a significant departure from a random distribution and indicates that the males are rather evenly spaced over the area. The eight-year history of territories on the study area was used to separate them into three categories: those occupied intermittantly, those occupied continuously by different birds, and those occupied -36- Figure 10. A sloping ridgeline that is open on the south side and heavily wooded on the north side which was often used by a territorial male blue grouse. -37- continuously by.the same bird for five or more years. The only relation­ ship noted between these groupings and the physical and vegetation data, other than that noted between- territory size and male age, was that -all the territories with continuous occupancy by the same male occurred at the higher altitudes. The positioning of•territories in relation to the density of coni­ fers on the study area is presented in Figure 11. Small coniferous thickets were associated with all territories even though they may not be so shown in the figure. A comparison between territories and-non-territories with respect to the relative percentages of open areas, thickets, and shrub cover, occurring in each is presented in.Figure 12. The-open areas were designated as. consisting of herbaceous vegetation with or without scat­ tered mature conifers. The composition of the non-territories with respect to the three categories should be indicative of the,composition of the areas not used by males. If this is so, then there -is apparently IeSs shrub, cover and open area, and more thicket, types incorporated in­ to the territories than in the unused ..portions ■ of the area. Considering just the thicket-and open -types, the opposite would probably.occur in areas.with abundant thickets and infrequent openings. Scale Yards L E GE ND J Op e n A r e a s ] S cattered Conifers D e n s e Conifers R o a d s - - - - S t o d v A r e a Bo o n d a r y Territory O c c o p a n c y <2 In te rm itten t # Unknown A C on tlnuoue-B a I W OO I Figure 11. The location of territories with respect to coniferous vegetation on the study area. Territories Non-territories I I I I i 40 50 60 Percent Conpesition Shrob * 80 Thicket Vegetative Class 90 100 I W VO I Figure 12. The composition of territories and non-territories with respect to the relative occurrence of three vegetative classes: open, shrub, and thicket. —40— Discriminant Function Analysis Four combinations of variables were used in the discriminant function analyses to.determine which were the most important. In the first analysis, all ten variables were used (Tables 5 and.6); in the second, thicket area, edge, and'trees per acre in the three dia­ meter categories were used; in the third, thicket area, edge, and average tree DBH were used; and in.the fourth, only thicket area, and edge were used.. The choice of the different combinations ,of variables was based on the results of the analyses of variance mentioned previ­ ously. A.condensed version of the results is presented in Table 9. The results of the individual analyses are included in Appendix Tables 10 through 13. The discriminant.function analyses suggest that the vegetational structure of male blue grouse territories can be distinguished from.that occurring "on areas .not used by breeding male, blue grouse. The analysis in which ten variables were used provided the best results. As the number of variables in the analysis was reduced, the' quality of.the results decreased. - Thus, all the variables measured, except possibly species composition of the thickets, were of some importance. There appeared to be considerable interaction between variables ; which made it rather difficult to choose the most important ones. How­ ever, a rather high degree of discrimination was shown when only thicket area, edge, and average tree.DBH were used in the,analysis, so these -41- TABLE 9. DISCRIMINANT FUNCTION ANALYSES OF TERRITORIES AND NON-TERRI­ TORIES IN WHICH FOUR COMBINATIONS OF VARIABLES WERE USED. Number of Variables Used in the Analysis 10 5 3 2 Territories Classified as: Territory Non-rterritory - 27(3)1/ 0 2 7 ( 6 ) 0 2 7 ( 7 ) 0 2 7 ( 9 ) 0 Non-territories Classified as: Territory Non-territory ■ 2 ( 1 ) 2 5 ( 3 ) 2 ( 1 ) 2 5 ( 4 ) 2 ( 1 ) 2 5 ( 6 ) 2 ( 1 ) 2 5 ( 7 ) I/ The number in parentheses is the number of territories or non- territories out ;of the total which had a less than 95 percent chance of being assigned to the indicated class by the discrimi­ nant functiono variables may be the most,pertinent ones. The most important aspect of the vegetational structure was probably the amount of edge provided by the thickets since this was the least variable measurement. LAND-USE AND SUCCESSIONAL RELATIONSHIPS Logging Selective logging has occurred on the study area since,1948, and there appears to have been no overall detrimental effects to the breeding habitat. This logging method may be beneficial because it opens up the canopy ,which allows the regeneration of trees in the form of scattered thickets. However, there are two side-effects that may be deleterious to the breeding habitat. First, this logging method often results in the destruction of thicket areas during log removal and spur road and skid trail construction.- . Secondly, large areas of slash, like large areas of shrubby cover, seem ..to be avoided by males, possibly because it obstructs their vision. Although the. clear-cut harvest method was not used on the study area because of the wide spacing of merchantable trees, it was commonly used on other nearby areas. If this method was used, on blocks of ten to 60 acres as recommended by Lutz (1957), it may be beneficial to blue grouse because it would ■, open .up the canopy and provide the opportunity for the regeneration of new thickets .• Large clear-cut areas, if re­ forested to even-aged stands, would not be suitable for blue grouse breeding habitat A relatively new practice on large clear-cut areas is a treatment, method commonly referred to as terracing (Figure 13). Such areas are contour furrowed by bulldozers at about '20 foot intervals and planted -43- Figure 13. Terracing on a clear-cut area in the Douglas-fIr vegetational zone near the study area. —44— to. ponderosa pine. The purpose.of this method -is to .produce conditions suitable for the growth of pine at elevations where it occurs naturally only as a fire successional stage. Aside from degrading the area aesthetically, this practice removes.for the present virtually all suit­ able cover and may delay reestablishment of blue grouse breeding habitat. Overall, logging must b e ■considered as being beneficial to blue grouse because it results in subclimax vegetation formerly produced by fire which is necessary for breeding habitat. However, the concept of multiple-use of forested areas should be taken into consideration where logging is to take place, and when possible, logging and reforestation- methods ' should take into.account the ecology of a.particular area as suggested by Lutz (1957). Silvicultural Practices Small portions of the study area were clear-cut by the U. S; Forest Service in an attempt to control heavy dwarfmistletoe infestations in thickets of Douglas-.fir reproduction.. This resulted in the destruction of several thickets (Figure 14) used by territorial male blue grouse and could be considered detrimental-to blue grouse breeding habitat. Ac­ cording to Childs (1963) , control of this parasite is not economically feasible in heavily infested and densely stocked young tree stands such as those that were cut on the study area. Because of this and because mistletoe spreads very slowly-(Pierce 1960), there appears to be little justification for attempts at such control. Also, according to Pierce —45- Figure 14. A Douglas-fir thicket destroyed in a dwarfmistletoe control program. It was once used by a territorial male blue grouse. — 46— (1960), it generally is more prevalent in situations where trees are ill-adapted to the particular site. So perhaps from the multiple-use viewpoint, attempts to control mistletoe should be limited to the more productive sites and to those that are not important blue grouse breed­ ing areas. Thinning, although not practiced on the study area, is another silvicultural method which could be detrimental to blue grouse breeding habitat. However, thinning is generally practiced only on large areas of young, even-aged stands of trees where it is .said to be.economically practical. Thus, the application of the practice is,most(likely re­ stricted to areas unfavorable for breeding blue grouse. Successional Relationships Fire was undoubtedly once the principal creator of blue grouse breeding habitat. With the advent of zealous fire control, logging has become the major disturbances factor responsible for creating new opportunities for succession to take place. However, the serai com­ munities following fire disturbance may differ from those following logging. These differences should be considered since early succes- sional or immature■climax stages are desirable ,for blue grouse breeding habitat. Breeding habitat in the study area was generally associated with a ponderosa pine fire successional stage in the Douglas-fir vegetational zone, or with immature climax stages in both the ponderosa pine and -47- Douglas-fir vegetational zones (Daubenmire 1953). The entire area consisted of uneven-aged stands of pine and.fir which, according to Weaver (1967), were probably the result of periodic burning. Most of the regeneration present is Douglas-fir which appears to be replacing the mature pine,, especially in the cutover areas. The oldest trees in territory thickets ranged from about 40 to 60 years. Thickets in which most trees were older,than 60 years were seldom used and there was: little or.no use of thickets under. 10 to 20' years of age.. The longevity of thicket use by males in this area is apparently about 40 to 50 years; On Vancouver Island where precipi­ tation is high, the■longevity of breeding areas is closer to 20 years (Bendell and Elliott 1967). A photo sequence of forest succession over a 40-year period fol­ lowing logging on a nearby area shows what might be expected on the study area (Figures 15-A, B , C, and D). The thickets shown in.Figure 15C are probably of about the age when the first use would take place. In a sequence with ponderosa pine reproduction (Figures 16-A and B), the thickets in Figure 16B (about 40 years old) would probably be ex­ cellent for male blue grouse territories. Presently, the regeneration of Douglas-fir thickets following logging on the upper portions of the study area seems adequate.. Se­ lective logging in this area may speed up succession because it favors Douglas-fir. On lower portions of the study area, there seems to be — 48- Figure 15. A photo sequence of forest succession over a 40-year period following logging. The photos were taken in 1909(A), 1927 (B), 1938(C) and 1948(D) (Courtesy U.S. Forest Service). -49- Figure 15. (Continued) -50- Figure 16. A photo sequence showing the growth of a ponderosa pine thicket over a 20-year period. The photos were taken in 1938(A) and 1958(B) (Courtesy U.S. Forest Service). little ponderosa.pine reproduction even•in areas that have been logged. This may .be due to.the fact that pine is more dependent than fir on fire for regeneration (LeBarron,.1957). -51- DISCUSSION Coniferous tree thickets appeared to be .the primary • component of male, blue grouse breeding territories, This.component occurred in all territories and males did,not establish territories- where-it was not present. Thickets used by males varied in number and.size but provided a .relatively constant amount of edge. Although the density of thicket trees was variable, territorial thickets of greater tree density were usually of less total area. Thickets not used by terri­ torial males were generally made-up of younger or older trees than those-used by males. The edges,of extensive thickets received moder­ ate use, but small isolated thickets were -rarely used. Extensive areas of shrubs were lacking in territories and are probably avoided by males. Shrub cover-occurred in much greater quantities on areas not used for territories than it did on areas defended by males. Shrubs that were present-on territories were usually of-a different-growth form. Since measurable differences do occur ,between used and unused. thickets, it seems .reasonable to assume that males select for certain : types -of thickets. In a discussion of habitat selection in birds, Hilden (1965) mentioned that habitat components such as thickets could be considered both a.proximate and - an ultimate factor,in habitat se­ lection, since they apparently stimulate,.the selection of a particular -53- site, and they provide shelter from both.enemies and adverse weather. Shrubby- areas probably evoke a negative response which may be stronger than the positive response toward a particular group of thickets. Once a territory has been established, a male will return to.it each successive year until he dies, regardless of changes in the vegetational,aspect (Bendell and. Elliott-1966). For this reasonj em­ phasis in a study such as this should probably be placed on the younger males whose territories have had little-chance to change. However, in the present study there was- relatively little difference between terri­ tories which had been occupied for more than-two years.and-those.which had been .occupied for two-years or less, even though-the area had been subjected to periodic selective logging. Open areas are also an-important territorial component, but their importance-was not stressed in this study because of their abundance. Since a negative correlation exists between - thicket/and open areas, the relative importance of one,in a given habitat is directly dependent on the other. Barring disruptions in the succession of a unit of forest, a situation where thickets are-at a premium and one where openings are at a premium denote the beginning and end, respectively, of suitability of that area for breeding male blue grouse. The-importance of-openings is, shown by the seeming preference, by males to hoot or display in areas where, at ground.level, unrestricted vision permits ready■surveilance of the territory. Prominences such as rocks,or stumps-are often used . -54- as hooting stations, and in the present study, logging roads were fre­ quently used. Using the distance-to-the-T-nearest-neighbor method of Clark and Evans (19,54) , it was determined: that ..the spacing of males tended toward an even distribution. This distribution may be due to territorial be­ havior of the males., an even distribution of the necessary vegetation, or a combination of these two factors. Spacing due to territorial behavior alone cannot be accepted in light of the yegetational data from territories and non-territories. Since territories do consist of components which are measurably different from non-territories, spacing of breeding male grouse is probably governed initially by habitat re-r quirements and/or selection and secondarily by territorial behavior,• In sparse populations, Bendell and.Elliott'(1967) found a random distribution of males in dense and very dense cover.which they attri­ buted to the influence of cover pattern.. However, in both dense and sparse populations in open coyer, they found that males-tended-toward ' even spacing which they attributed to territorial behavior. ' Although males spend less than•one-third of each year on terriv tories, this is the period when■their■display activities in open areas . would probably make them more vulnerable to predation. Thus, the history of territorial occupancy may be indicative of the relative de­ gree of security provided by the vegetation.. Eng (1959) reported that the greatest .loss of ruffed grouse (Bondsa umbeVlus) to goshawks. -55- (Aocip-iter gentitis) was during the spring drumming season. Territories that were occupied continuously during the eight years were generally smaller than those that were occupied intermittently (I.79 acres vs. 2.33 acres), while most other characteristics were similar. The size difference could be indicative of the aggressiveness of the male as Watson (1964) found in red grouse (Lagopus sogtieus).- Since thicket size and other variables were similar, the security level may in.some way be related to the distributional patt.em of thickets, which,, unfortunately, was not investigated. The larger average size of intermittently used territories in conjunction with the fact that total thicket areas were similar indicates that the thickets may-have been more widely dispersed. . Birds occupying such territories were probably more, vulnerable to predation, particularly by avian predators. However j, it should be noted that -,of the six ..predator-killed males found, all appeared to be victims of coyotes (Canls- Zatvcxns). The greater density and.smaller total area of territory thickets composed mostly, of Douglas-fir (Table 7) suggests that they provide better protection than thickets of ponderosa.pine. Since different tree species have different -growth forms, the species comprising most, of the thicket trees may be.relatively important, although it is basically the growth form,rather than the tree species itself that is of major importance. Gullion and Marshall (1968) concluded that it / was the growth form or physical characteristics of trees rather than —56— the species that affected ruffed grouse Survival in Minnesota. Longevity of males did not seem to be influenced by habitat type (ponderosa pine vs. Douglas-fir zones) as was reported for ruffed grouse by Gullion and Marshall (1968). However, differences in longevity as related to habitat types were probably more easily deter­ mined for ruffed grouse males since their annual turnover.rate is about 50 to 70 percent (Eng 1959; Frank 1947; and Gullion and Marshall 1968) compared to about 30 percent for blue grouse males (MussehI and Schladweiler 1969; Bendell and Elliott 1967). Most of the measured characteristics of thickets were inter­ related and dependent on age. As a thicket increased in age, natural processes would increase the average tree DBH and the average live branch height and decrease the tree density. Also, thicket area.and edge might increase slowly because of regeneration and radial increment at thicket perimeters. Species composition might-shift because of interspecific.competition between pine and fir. Unfortunately, definite relationships such as this are difficult to quantify because of the variation in site quality encountered in mountainous terrain. In an area that is relatively homogenous with respect to site quality, it may be possible to measure a lesser number of selected variables and determine from them the suitability of thicket areas for blue grouse breeding habitat. -57- The discriminant function analysis proved to, be quite valuable - in evaluating male blue .grouse territorial characteristics. Using ten variables, 96'percent ..of. the 54 areas (27 territories and 27 non­ territories) were classified correctly. This high degree of discrimi-. nating power was made possible through a known history of territories which in turn permitted separating areas used for territories from those which were not. In other studies using this statistical tech­ nique (Klebenqw 1969) , problems arose because there was -.no assurance that selected areas were not suitable for a particular organism, even though it-was not found there. Selective logging, and the resulting forest succession, is . probably -necessary fo maintain this area as suitable blue grouse breed­ ing habitat. This .is particularly true in the absenceacetoseI la erispus. CHENOPODIACEAE Chenopodiumtalbum Monqlepis -nuttalliang AMAHANTHACEAE Amaranthus ret^ oflexus. PORTULACEAE Claytonia lanaeolata linearis . perfoliata Lewisia•rediviva CARYOPHYLLACEAE Arenaria aongesta- Cerastium ar;pense- uulgatum ■ Lyqhnis alba. Silene cuoubalus .• menziesii noetiflora - Vaqoaria -se.getalis RANUN CU LA CE AE Anemone patens Clematis ,oolumbiana linqustiai folia. Delphinium bioolor Ranunculus aaris oymbalaria' glaberrimus - Thalictrim oacidentale BERBERIDACEAE Berberis .repens CRUGIFERAE Alyssum alyssoides Arabis holboellii ■ Camelina miarocarpa ■ Capsella bursa-pastoris Desaurainia pinnata Common-Name Sulfur eriogonum, Prostrate -Imotweed Douglas knotweed, Sheep sorrel■ Curl dock■ Lamb 1s quarter Nuttall monoIepIs Redroot, ,pigweed Western spring beauty Narrowleaved- spring beauty Miner's lettuce Bitterroot Ballhead sandwort Field chiekweed Big chiekweed White cockle Bladder siIene Menzies silene - Nightflowering silene .. Pink cockle Pasque flower Rock ' clematis Western white clematis Low larkspur . Tall buttercup ' Shore,buttercup Sagebrush buttercup Western meadow rue Oregon grape Pale alyssum Hoiboell rockcress . Littlepod false-flax Shepherd's purse Pinnate tansy mustard —62- TABLE 2, (CONTINUED) Taxan ____________ . Drdba eras si folia, ' nemorosa Erysimum asperum ■ Physaria didymoaarpa CRASSULACEAE ■ Sedum stenopetalum- SAXIFRAGACEAE Heuahera aylindriaa ' Lithophragma.parviflora Saxifraga rhomboidea GROSSULARiACEAE ■ Ribes aereum sertosum HYDRANGEACEAE , Philadelphus ,lewisii ROSACEAE Amelanahier alnifolia ■ Cerpaoaarpus -ledifoiius : Fragariaaoirginiana Geum trif lorum . Physoaarpus 'maloaaeus Potentilla arguta- glandulosa, ■ grgailis Prunnus .ameriaana- virginiana Purshia -tridentata.. Rosa woods ii ■ Rubus idaeus pavviflprus ■ Spiraea.betulifolia ' LEGUMINOSAE ■ Astragalus sp.• Glyayrrhiza lepidota Lupinus ‘serioeus ■ Mediaago lupulina Melilotus alba ’ officinalis Trifolium hybridum ■pratense Rocky Mountain draba Woods 'draba Plains; wallflower Common twinpod- Yellow stqnecrop . Roundieaved allumroot Smallflower weodlandstar Diqmondleaf saxifrage Squaw'currant . Redshoot gooseberry Mock-orange 1 Western serviceberry . Curl-leaf mountain mahogany Virginia strawberry Prairie:smoke 1 Ninebark Tall cinquefoil Gland cinquefoil■ Northwest cinquefoil Wild- plum Chokecherry Antelope bitterbrush Wood's rose Red raspberry Thimbleberry White spiraea Milkvetch Wild licorice Silky lupine Black mqdic. White sweetclover •' Yellow sweetclover Alsike clover Red clover' Common. < Niame . __________ —63- TABLE 2. (CONTINUED) Taxon ■_____________ GERANIACEAE . Erodium eieutarium. Geranium..- oarotiniimum visoosisimum EUPHORBIACEAE Euphorbia, egula ■ CELASTRACEAE■ Paqhistima myrsinites ACERACEAE Aaer glabrwn ■ VIOLACEAE Vi& la ■ adunoa ■, orbiouiata ■ LOASACEAE Mentzelia dispersa CACTACEAE • Opuntia.polyaqantha ■ ONAGRACEAE Epi lobium angus tifo Hum glaberrimum- minutum Gayophytum nuttallii Oenothera biennis- UMBELLIFERAE Lomatium disseatum tritematum Osmorhiza ocaidentalis ■ Periderddia gairdheri CORNACEAE Cornus stolonifera- ERICACEAE Aratostaphylos uva-ursi ' Vaaainium -.oaaidentale' PRIMULACEAE ' Dodeaatheon pauaiflorum . GENTIANACEAE Gentianella amerella APOCYNACEAE Apoaynum androsaemifolium Common Name Alfilaria Carolina geranium • Sticky geranium ■ Leafy spurge Myrtle pachistima ■ Rocky Mountain maple - Western violet Western round-leaved violet ; Scattered stick-leaf Plains pricklypear Fireweed Glaucous willow-herb ■ Small willow-herb. Nuttall1S groundsmoke Rydberg's evening primrose.. Nineleaf lomatium Western sweefcroot Yampa, Red dogwood . Kinikinnick Western huckleberry Southern shooting star Annual gentianella Spreading dogbane -64- Taxon ■ Common ..Name v TABLE 2. (CONTINUED) Narrowleav.ed- cqLlomia POLEMONIACEAE Collomia -,.Iineavis - Mievostevis gvaeilis- • HYDROPHYLLACEAE • HydvophyHum eapitatum- Phaeelia hetevophyI la ' lineavis BORAGINACEAE ' Cvyptantha .bvadbuviana Cynoglossum-offieinale. Lappula- vedowskii, Lithospevmum vudevale Mevtensia oblongifolia LABIATAE Agastaehe uvbieifolid Monavda -fistulosa Pvunelta vulgavis- SOLANACEAE ■ Solanum. duleamava SCROPHULARIACEAE Castillega hispida miniata Collinsia- pavvifIova ■ Mimulus- guttatus- Ovthoeavpus -tenuifolius Pediculavis -.eontovta Penstemon albevtinus pvoeevus wileoxii Vevbaseum thapsus Vevoniea amevieana pevegvina ' sevpyllifolia,, PLANTAGINACEAE , Plantago mag’ov, puvshii - RUBIACEAE Galium apavine ■ boveale- tvifidum ■ Waterleaf .. Virgate 'phacelia ■ Linear-leaf phacelia Miner Is candle. Hound*s tongue Western .stick tight - Western gromwall Oblongleaf bluebell Nettle-leaf giant hyssop Horsemint - Common selfheal Climbing nightshade ■ Scarlet Indian paintbrush Blue-eyed Mary Common monkey-flower.,. Thin-Ieaves orth'ocarpus Coiled pedicularis Alberta penstempn Littleleaf penstemon Wilcox.penstemon■ Flannel mullein' American speedwell Purslane speedwell .■ Thymeleaf speedwell ■ Broadleaf plantain Woolly plantain Northern bedstraw -65- TABLE -2. (CONTINUED). Taxon ' Common Name■ CAPRIFOLIACEAE Linnaeec Loveaiis- Twin-flower < Sambuaus me lanoaavipa Black elderberry Sympheviaavpos atbus Common snowberry - VALARIANACEAE Valeviana dioiaa- ■ Marsh valeriana oaaidentaiis Western valeriana CAMRANULACEAE Campanula votundifolia Roundleaf harebell - COMPOSITAE Aahillea millefolium. Yarrow Agosevis -glauaa-- Pale agoseris Anaphalis mgvgavitaaea.. Pearly everlasting Antennar^a Vaaemosa Raceme pussyto.es '■ vosea■ Rose pussy toes Avniaa aovdifolia ' sovovia ■ Avtemisia -fvigida Fringed sagewprt ludoviciana Cudweed sagewort' miahauxiana ■_ Michaux.sagebrush tvidentata Big sagebrush■ Astev foliaqeus Leafybract aster Balsamovhiza Sagittata- Arrowleaf halsamroot.-. Cehtauvea maaulosg Spotted knapweed Chvysop,sis villosa Golden-aster Chvysothamnus- visaidif lovus Green rabbitbrush Civsium avvenSe Canada thistle ; vulgave . Bull,thistle Cvapis .atvabavba Evigevon aavis.: Bitter fleabane aanadensis • Horseweed fleabane • aompositus Fernleaf fleabane • divevgens' Spreading fleabane philadelphiaus spsoiosus , Oregon fleabane subtvinevvis •- Three-veined fleabane Filago avvensis ■ Field fluffweed Hievaaium aynoglossoides Houndtongue hawkweed Laatuag sevviola ■ Matviaavia matviaavioides Pineapple weed Miovosevis nutans Nodding microseris -66- TABLE 2, (CONTINUED) Taxon ' Common - Name ■- Seneoie oanus- Woolly groundsel - lugens • SeUdage misseuviensis- Tanaoetvm vuigave- Tanstsciewn ■ effioihale , ■ Tragopogen-dubius Goldenrod Common■tansy Common dandelion • Common salsify -67- TABLE 10. RESULTS OF THE DISCRIMINANT .-FUNCTION ANALYSIS .IN WHICH ALL T E N ■VARIABLES WERE USED Terr. No. Classi­ fied as ' Probability of Correct Class.— '- Non-terr. No. Classi­ fied as : Probability of Correct - Class. 10 3 A T 0.999 10 3 A N 0.989. 104 T 0.999, 104 N 0.991 105 T 0.999 ' 105 N 0 : 9 9 7 42 • T 1.000 42 N 0.955 32A T 0.902 32A N 0,991 32B T 0.996 32B N 0:998 .30 T ' 0.933 30 N 0.999 30A T 0.991 30A N 0,994 65 T 0.998 65 N 0.997 73A T 0.999 73A N 1.000 54 T 0,955 54 N 0.999 94 T 0.992 94 N 0.994 94A ' T 0.998 94A T 0.877 62 T 0.999. 62 N 0:887 38 T 0.966 38 N 0.999 3 BA T 0.999 - 38A . N 0.997 72 . T 0.999 72 ■ N 0.999 27 T 0.959 27 N- . 0.995 47 T 0.997 47 N 0.999 48 T 0.965 48 T 0 . 9 9 7 51. T 0.999 51', N 0.995 53 T 0.999 53-. N 0 . 9 9 9 52 : T 0.971 52 . N 0.999 82 ■ T 0.728 82 N 0.999 115 T 0.999 115 N • 0 . 9 9 9 • 116 T • 0.999 116 N 0.999 78 T 0.957 78 N 0.985 I/ T stands for territory - and N for non-territory. 2/ Probability that the area was classified correctly by the discrimi­ nant function. - 68- TABLE ,11. RESULTS OF - THE DISCRIMINANT FUNCTION ANALYSIS IN WHICH FIVE VARIABLES WERE USED (THICKET SIZE, EDGE, TREES PER ACRE IN, THREE-CATEGORIES). . Terr.. No. Classi­ fied a s ' Probability of Correct Class.— / Non-terr. No. Classi­ fied as: Probability - of - Correct'Class.. 10 3 A T 0.996 10 3 A N 0.953 104 T 0.999 10.4 N 0.992- 105 T . 0.999 105 N 0.997 42 T 1.000 42 ' N 0.937 32A T 0.873 32A N ■ 0.957 32B T- 0.998 32B . N- 0.997 30 T 0.915 30 N 0.999 30A T Q,980 30A N 0.985 65 T 0.995- 65 N 0.996 - 73A T • 0.999 73A. N 0.999 54 T • 0.953 54 N 0.999 94 T 0.987 9 4 N 0.995 94A T 0.996 94A T 0.833 62 T ■ 0.998 62 N- 0.931 38 T . 0.975 38 N- 0.999 38A T 0 . 9 9 9 3 8 A N 0.996 72 T 0 . 9 9 9 72 N 0.999 27 T 0.948 27 N 0.990 47 T 0.995 47 ' N 0.999 48 T ' 0 . 9 7 2 48 T 0.995 51 T . 0.999 51 N 0.994 53 T-.. 0.999 53 N 0.999 52 T • 0,837 52 N ■ 0 . 9 9 9 82 T - 0.600 82 N . 0,999 115 T 0 . 9 9 9 115 N • 0.999 116 T 0 , 9 9 6 116 N - 0,992 78 T 0.934 78 N 0.989 I/ T stands for territory and N for non-territory. TlI Probability that the area was classified correctly by the discrimi­ nant ■ function.. —69— T A B L E -12. RESULTS OF THE DISCRIMINANT FUNCTION ANALYSIS IN WHICH THREE VARIABLES WERE USED (THICKET■SIZE, EDGE, AVERAGE DBH). Terr. No. Classi- . fied asi— Probability of Correct C l a s s / Non-terr. No. . - Classir fied as: Probability of Correct'Class. 10 3A T 0.986 10 3A N 0.959 104 T 0.999 104 N 0.991 105 T; ■ 0.990 105 N 0.663 42 T 0.999 42 ' N 0.939 32A T- 0.942 32A N 0.931 32B T 0.997 32B N 0.999 30 T 0.903 30 • N . 0.999 30A T - 0.943 30A N 0.977 65 T - 0.990 65 N-- 0,997 73A T 0.999 73A N 0,999 54 T 0.931 54 N 0,999 94 T - 0.984 94 N 0.999 . 94A T - 0.990 94A ■ T 0.937 ' 62 T 0.999 62 N 0.948 38 T 0.958 3 8 N 0.999 38A T 0.999 38A N 0.999- 72 T 0.995 72 N 0.998 27 T 0.924 27 N 0.975 • 47 T 0.-964 47 N- 0.999 - 48 ' T 0.962 4 8 T 0:996 51 T 0.995 51 N 0.979 53 T 0.999- 53 N 0.999 • 52 T 0.588 52 N 0.999 ■ 8 2 T . 0.573■ 8 2 N 0.993 115 - T 0.999 115 N 0.997 116 T 0.995 116 N 0,994 78 ' T 0.958 78 N 0.983 I/ T stands for territory and N stands.for non-territory, 2/ Probability that the area was classified correctly by :the discrimi­ nant function. — 70- TABLE ,13. RESULTS OF THE DISCRIMINANT FUNCTION ANALYSIS IN WHICH TWO VARIABLES WERE USED (THICKET SIZE, EDGE). Terr. No. Classi­ fied as Probability of• Correct Class.— ' Non-terr. No. Classi­ fied as : Probability of Correct Class. 10 3 A T 0.984 10 3A N 0,660 104 T 0.999 104 N ■ 0.991 105 T 0.989 105 N 0.897 42 T 0.999 42 N 0.976 32A T 0.923 32A N • 0.879 32B T 0.996 32B ■ N 0 . 9 9 9 30 T 0.853 30 N 0.999 30A T 0.909 30A N 0 , 9 6 7 65 T 0,980 65 N 0.995 73A T 0,998 73A N 0,999 54 T 0.863 54 N- 0.997 94 T ' 0.960 94 N 0,999 ■ 94A T 0.982 94A T 0.931 62 T 0 . 9 9 8 62 N 0.969 38 T 0.894 38 N 0.999 38A T 0 . 9 9 9 38A N 0.999 72 T ' 0 . 9 8 8 72 N 0.995 27 T 0.875 27 N- 0.934 47 T ; 0.945 47 N- 0.999 48 T 0.952 48 T ■ 0.996 51 T 0.991 51 N 0.928 53 T 0.999 53 N 0 , 9 9 6 52 T 0.643 52 ■ N 0 . 9 9 8 82 T • 0.842 82 N- 0.998 115 T 0.999 115 N - 0.995 116 T 0.988 116 N 0.995 78 T 0.953 78 N 0.981 I/ T stands ■ for territory, and N stands for non-rterritory. 2J. Probability that the area was classified correctly by the discrimi­ nant function.. LITERATURE ■ CITED Bendefll, J. F. 1954. 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