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Graduate Student Theses, Dissertations, & Professional Papers Graduate School
1974
Distribution and population characteristics of bighorn sheep near Thompson Falls in northwestern Montana
Gerald Warren Brown The University of Montana
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Recommended Citation Brown, Gerald Warren, "Distribution and population characteristics of bighorn sheep near Thompson Falls in northwestern Montana" (1974). Graduate Student Theses, Dissertations, & Professional Papers. 6510. https://scholarworks.umt.edu/etd/6510
This Thesis is brought to you for free and open access by the Graduate School at ScholarWorks at University of Montana. It has been accepted for inclusion in Graduate Student Theses, Dissertations, & Professional Papers by an authorized administrator of ScholarWorks at University of Montana. For more information, please contact [email protected]. DISTRIBUTION AND POPULATION CHARACTERISTICS
OF BIGHORN SHEEP NEAR THOMPSON FALLS
IN NORTHWESTERN MONTANA
By
Gerald W. Brown
B. A ., University of California at Riverside, 1970
Presented in partial fulfillment of the requirements for the degree of
Master of Science
UNIVERSITY OF MONTANA
1974
Approved by:
Chairman, Board of Examiners
Dean/ Graduate School
! i 7 r Date UMI Number: EP37311
All rights reserved
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ProQuest LLC. 789 East Eisenhower Parkway P.O. Box 1346 Ann Arbor, Ml 48106 - 1346 ACKNOWLEDGMENTS
I am especially grateful to Dr. Bart W. O’Gara, major advisor for this project, for assistance and guidance throughout this study and for critical review of the manuscript.
Thanks are also due other members of the committee, Drs.
P. L. Wright and Bob Ream, and Mr. R. P. Weckwerth for review of the thesis. Dr. Lee Metzgar provided helpful suggestions on inter pretation of population data.
Gary Halvorson, Jack Fisher, and Dick Smith of the U. S.
Forest Service, Lolo National Forest, provided helpful graphic m a te r ia ls.
I appreciate the cooperation, use of equipment, and flight time provided by the Montana Fish and Game Department.
My wife, Chris, assisted with some of the trapping and provided the patience and understanding sorely needed during this study. My brother-in-law. Bill Unbehend, also helped with some of the trapping. Numerous others helped in various ways, and to them I say thanks.
Financial support for this project came from the Montana
Cooperative Wildlife Research Unit (U. S, Fish and Wildlife Service,
University of Montana, Montana State Fish and Game Department, and
Wildlife Management Institute cooperating).
ii TABLE OF CONTENTS
P age
LIST OF TABLES ...... v i
LIST OF FIGURES ...... v iii
CHAPTER
I. INTRODUCTION ...... 1
II. DESCRIPTION OF THE STUDY AREA .... 6
L o c a t i o n ...... 6 G e o l o g y ...... 6 Land U s e ...... 9 C l i m a t e ...... 10 V e g e t a t i o n ...... 13
III. MATERIALS AND METHODS...... 21
T r a p p in g ...... 21 Group F i d e l i t y ...... 26 Winter Centers of A ctivity...... 26 P a r a s it e s 2 7 Food Habits 2 7 C ensus in g ...... 28 O b serv a tio n s 2 9
IV. RESULTS ...... 31
T r a p p in g ...... 31 Salt Lick U tilization ...... 34 C o l l a r s ...... 37 C o n d itio n ...... 38 D e m o g r a p h y...... 38 Population s e g m e n t s ...... 38 Population e s t i m a t e s ...... 39
111 Page
A g e-se x c o m p o s it io n ...... 42 Survivorship ...... 45 Group size and com position ...... 45 Group fid elity ...... 49 Distribution and Movements ...... 51 Winter range ...... 51 Winter centers of a c tiv ity ...... 60 Spring range ...... 62 L a m b in g ...... 63 Summer ran ge ...... 63 Summer activity centers...... 64 F a ll r a n g e ...... 66 Habitat u s e ...... 67 Diseases and P arasites...... 67 Lung an alyses...... 71 Ectoparasites ...... 71 P r e d a tio n ...... 73 A c c id e n ts ...... 74 Food H abits ...... 75 Horn Growth ...... 79
V. DISCUSSION AND RECOMMENDATIONS .... 83
T r a p p in g ...... 83 Salt lick utilization...... 84 C o l l a r s ...... 85 C o n d itio n ...... 86 D e m o g r a p h y...... 89 Population segm ents ...... 89 Age-sex com position ...... 90 Group size and composition ...... 92 Group fid e lity ...... 93 Distribution and Movements ...... 94 Winter range ...... 95 Winter centers of a c tiv ity ...... 95 Spring range ...... 96 L a m b in g ...... 97 Summer ran ge ...... 97 Summer centers of activity...... 98 F a ll r a n g e ...... 100 Diseases and P arasites...... 100 Population Regulation ...... 103
iv Page
Food H abits ...... 104 Horn Growth ...... 106 Management O ptions ...... 108 Natural population regulation ...... 108 Three-fourths horn harvest ...... 109 Trophy ram s...... 109 Maximum productivity...... 109
VI. SUMMARY ...... I l l
LITERATURE CITED ...... 113
APPENDIX
A. LIST OF PLANT SPECIES ...... 118
B. WINTER AND SUMMER ACTIVITY CENTERS AND MOVEMENT PATTERNS OF BIGHORN SH EEP ...... 126
C. ANNUAL HORN GROWTH IN BIGHORN RAMS . . 134 LIST OF TABLES
TABLE Page
1. Climatological sum m ary ...... 11
2. Age, sex, live weight, location and date of capture, and marking system for 20 bighorn sheep captured during summer 1973 32
3. Sex and age classification of bighorn sheep by month, 15 May 1973 to 15 May 1974 43
4. Age classification of free roaming bighorn rams by annulation counts...... 44
5. Group size frequency distribution from observation of 311 bighorn g ro u p s ...... 47
6. Seasonal change in mean group size for each of the age-sex categories ...... 48
7. Mean seasonal coefficients of association for marked bighorns and percentages in five frequency classes, June 1973-May 1974 .... 52
8. Relocation data for radio collared ewe, 21 June- 16 S e p t e m b e r ...... 59
9. Activity ranges of marked bighorn sheep during winter and summer, as determined by standard d i a m e t e r s ...... 61
10, Comparison of winter and summer standard diameters for marked bighorn s h e e p ...... 65
11. Percentage of bighorns observed on each of three habitat groups and three landform types, for each sea so n ...... 68
VI TABLE P age
12. Comparison of protostrongylld larval output for various age and sex classes as determined from 100 fecal samples collected between April 1973 and January 1974 ...... 69
13. Frequency distribution of protostrongylid larval output for bighorn sheep from both herd segments, as determined from 50 fecal samples each, collected during 1-12 April 1974 ...... 70
14. Numbers of lungworms and larvae found in six respiratory tracts from bighorn sheep shot by hunters or killed by veh icles...... 72
15. Rumen analyses of four rams killed during fall 1973 and two ewes killed during April 1974 ...... 76
16. Summer food habits of bighorn sheep as determined from examination of nine feeding sites during June and J u ly...... 77
17. Major plant species consumed by bighorn sheep, by month, from October 1973 to April 1974, as determined from direct observation .... 78
18. Age and horn size for bighorn sheep taken by resident hunters between 1968 and 1973, and rams shot from original herd ...... 80
19. Average annual increment of horn growth as determined from 21 rams from the present population, and three rams from the original h e r d ...... 81
20. Winter and summer activity centers and movement patterns of bighorn sh eep ...... 126
21. Annual horn growth in bighorn r a m s ...... 134
vxi LI3T OF FIGURES
Figure Page
1. Location and demarcation of study a r e a ...... 3
2. Composite aerial photograph of study area 8
3. Vegetation composition map for study area 14
4. Topographic map of southern portion of sheep range ...... 22
5. Photographs of bighorn sheep 24
6. Datum collection form sheet 30
7. Chronological distribution of bighorn captures . . . 35
8. Chronological distribution of bighorn salt lick utilization ...... 35
9. Transplant sites and post-transplant dispersal p a tte r n s...... 40
10. Monthly ewe:lamb ratios...... 46
11. Dissociation of young rams from ewe groups, first 5 years of a g e ...... 50
12. Seasonal key use areas...... 53
13. Summer movements of radio-equipped bighorn ewe . 54
14. Annual pattern of movements for male lamb No. 446 ...... 55
15. Annual pattern of movements for male lamb No. 436 ...... 56
Vlll Figure Page
16. Spring pattern of movenients for easily recognizable 8-year-old bighorn ra m ...... 57
17. Pattern of movements for individually recognizable bighorn ewe from the Thompson River herd u n it ...... 58
18. Grid map showing winter and,summer activity centers and movement patterns of bighorn s h e e p ...... 133
IX CHAPTER I
INTRODUCTION
Set on (192 9) estimated between 1. 5 and 2 million bighorn sheep (Ovis canadensis) in North America during the 1880's. By the early 1940's, this species was exterminated in 4 of the 15 western states they formerly inhabited. Within the remaining states, their distribution was reduced to approximately 10 percent of their former range, and their numbers diminished to less than 20, 000 (Buechner
1960). Probable causes for their decline are 1) forage competition with domestic livestock, 2) diseases introduced by domestic livestock,
3) conversion of mountain grasslands into timber lands or sagebrush deserts (Morgan 1970), and 4) indiscriminate hunting.
In an ^attempt to rectify th is situation, se v e r a l sta tes initiated transplanting programs into historic bighorn ranges (Yoakum 1963).
The Montana Fish and Game Commission began transplanting activities in 1942; the original motivation for doing so was apparently an attempt to curb inbreeding in remnant, native populations (Guthrie 1945).
During the period 1942-1969, 13 transplants were made into historic sheep ranges with variable results. One such plant was made into the
Thompson Falls area of northwestern Montana. Couey and Schallenberger (1971) list this transplant as ''surviving, " although the
population is steadily increasing, and provides annual harvests of
3/4-curl rams on a permit basis.
The historic presence of mountain sheep in the Thompson
Falls area was documented by various authors. In his journals,
covering 1808-1812, David Thompson referred to bighorn sheep near
Thompson Falls (White 1950). During the 1830*s and 1840's, fur
trappers described sheep as numerous in the area (Cox 1931, Ferris
1873). The Upper Kalispell Indians hunted bighorns from the big slide
area, on the south side of the Clark's Fork River, approximately
8 miles northwest of Thompson Falls, to Paradise, approximately
35 miles southeast of Thompson Falls (Smith 1937) (Fig, 1). In the
late 1800's, sheep were sighted approximately 50 miles up the
Thompson River near McGregor Lake. At that time, local residents
felt that sheep ranged over a large area, including both sides of the
Clark's Fork and Thompson rivers. Shortly after the turn of the
century, these sheep were greatly reduced in numbers and their range
drastically restricted. Couey (1950) stated that by 1942 the Thompson
Falls sheep numbered approximately 50 and were restricted to a 4- mile area east of the Thompson River and north of the Clark's Fork
River. Five years later, 8-10 animals inhabited this area, according to U.S. Forest Service personnel (Buechner 1960). Between 1948 and
1959, sheep were not sighted in the area and presumably no longer Fig. 1. Location and demarcation of study area,
Scale: 1 inch = 2.3 m iles. t-'K
Mt
' '■ t r f ' II.'.q _____
.«î^S^u; Hole
,^"^;/Q(/s*3mî;
lA I h<=> r t a
|Kaltspe 11 Ic'Cregor Lake mi. Thompson F<
iMissou la existed there.
The present bighorn population near Thompson Falls is the result of a 1959 transplant. On 15 May 1959, 13 bighorns were trans planted from the Sun River herd into the Munson Creek area between
Thompson Falls and Plains. This group consisted of eight ewes and five rams. Subsequently, on 26 September, six additional animals
(five ewes and one ram) from Wildhorse Island were released near the
West Fork of the Thompson River (Warden Cheney pers. comm. ).
Since then, sheep were reported at diverse locations around Thompson
River and Munson Creek. These animals expanded their range to include a block of mountainous terrain encompassing approximately
140 square miles. Other large indigenous mammals inhabiting the area include moose (Alces alces), elk (Cervus canadensis), mule deer
(Odocoileus hemionus), white-tailed deer (Odocoileus virginianus), mountain goat (Oreamnos americanus), black bear (Ursus americanus), grizzly bear (Ursus arctos), coyote (Canis latrans), red fox (Vulpes vulpes), mountain lion (Felis concolor), and bobcat (Lynx rufus).
Numerous smaller mammals are native to the area.
This investigation, designed as a pilot study to assess the current status of mountain sheep in the Thompson Falls area, was conducted from March 1973 through May 1974, Specific objectives were to investigate:
1) sheep distribution and define seasonal, key-use areas; 2) population characteristics, i.e ., productivity, mortality, age-sex ratios and population numbers;
3) the incidence of lungworm as an indicator of range conditions;
4) the interchange of individuals from widely separated locations; and
5) seasonal food habits. CHAPTER II
DESCRIPTION OF THE STUDY AREA
Location
The study area is situated along the north side of the Clark's
Fork River Valley midway between Plains and Thompson Falls,
Montana. Map coordinates are 155®00' - 115° 15' W. longitude and
47°30' -47®45' N, latitude. Fig. 1 outlines the area in which this investigation was conducted. Occasional reports of sheep outside this area were received, but I never observed mountain sheep outside the designated boundaries of Fig. 1.
G eology
Geologic structure and geomorphie features are treated in depth by Alt and Hyndman (1972) and Aid en (1953). Local topography was greatly influenced by massive Glacial Lake Missoula. There is evidence that the Lake inundated the landscape to 3, 500 foot elevation.
Approximately 12,000 years ago, the glacial ice dam near Sandpoint,
Idaho, ruptured, releasing the Lake's waters. Draining of the Lake was rapid, with discharge estimated at 8 to 10 cubic miles per hour
(Alt and Hyndman, ibid. ). The tremendous out rush of water had a pronounced scouring effect on the narrow Clark's Fork Valley between
Plains and Thompson Falls. Lake sediments and residual soils were washed from the Valley walls resulting in exposure of parent material.
Poorly developed soils and numerous talus cones emanating from rugged crags of exposed bedrock, characterize this section of the
V alley.
Glacial activity was minimal, being restricted to a few small cirque basins along the western perimeter of the study area, A small local glacier responsible for carving the eastern flanks of Mount
Headley may have had a branch segment extending a few m iles down the West Fork of the Thompson River (Alden 1953). The main
Thompson River Valley is the result of fluvial geomorphic processes.
For 15 miles below the confluence of Little Thompson River, the main
Thompson deeply bisects the landscape, winding southwesterly through a narrow rocky-walled corridor before converging with the Clark's
Fork, Several sharp-edged interfluves characterize the topography above the corridor walls. Fig. 2 illustrates the topographic features for the entire study area.
The sheep range is located in the southeast end of the Cabinet
Range. This range, formed between 600 and 1, 500 million years ago, is composed of Precambrian sedimentary sandstone and mudstone of the extensive Belt Series, common to western Montana. The Burke and Wallace Formations consisting of nearly pure quartzites, Fig. 2. Composite aerial photograph of study area.
(Scale approximates that of Fig. 1. ) à m $
: # # N ': # ^
% èl'if. 'Vt " * ^ \ i a r r > .« ’fdfeife. , ' * f-' s ' */v; siliceous shale, and laminated argillites underlie a major portion of this area (Alden 1953). Land U se Principal land uses on the study area are mining, ranching, agriculture, and logging. Mining is presently of little importance, but since 1800 copper and silver were extracted sporadically from mines located a few miles above the mouth of the Thompson River (Anon. 1953). Ranching and agriculture are of a subsistence nature, being generally restricted to the narrow river terrace between the Clark's Fork River and its steep valley escarpments. The timber industry is the chief source of income. Timber management on most of the area is administered by the U. S. Forest Service and the area falls within the Lolo National Forest. Private corporations such as U. S. Plywood and Burlington Northern manage timber on their holdings in the northern portion of the study area. Domestic livestock grazing was historically of more impor tance than at present. Following the extensive fires of 1910, the U.S. Forest Service encouraged sheep ranchers from Washington and Oregon to graze their stock on burned-over National Forest lands in the Thompson Falls region (Puphal pers. comm. ). In 1940, a sheep rancher moved onto the terrace at the base of Koo-Koo-Sint Ridge and maintained between 200 and 500 head of sheep until 1960 (Dykstra pers. 10 comm. ). Possibly, the decline of bighorns was related to introduction of domestic sheep into that area. Cattle grazing on National Forest lands is currently of minor importance, being restricted to the eastern and northern portions of the study area. C lim ate The Clark's Fork River Valley between Plains and Thompson Falls reputedly has the mildest weather conditions in northwestern Montana. This is due mainly to the northwest-southeast alignment of mountain ranges. The Coeur D'Alene Range to the southwest blocks out much of the moisture-laden air moving inland from the Pacific Coast, while the Cabinet Range to the northwest shelters the area from cold air m asses moving south from Canada. Short winters with much cloudiness and overcast skies characterize the area. Summers are warm with many clear, sunny days from late June into September. Severe storms are uncommon. Prevailing winds are from the west and southwest and generally mild. Climatological data for the U.S. Weather Bureau are collected by the Montana Power Company at their hydroelectric plant in Thompson Falls, approximately 6 miles west of the study area. Table 1 lists mean and extreme temperatures and precipitation by month, for a 30-year period ending in 1970 (U.S. Dept, of Commerce, Climato logical Summary). U S. DEPARTMENT OF COMMERCE NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION ENVIRONMENTAL DATA SERVICE IN COOPERATION WITH COOPERATIVE EXTENSION SERVICE CUMATOGRAPHY OF THE UNITED STATES NO 20 - 24 LATiniDl 47O 36'N CUMATOLOGICAL SUMMARY STATION THOMPSON FALLS, MONTANA LONOITUDK 115° 2 2 ’W lUV. (QEOUHD) 2 ,3 8 0 f t . M1AN3 AND EXTRKUIS FOR PERIOD 1941-1970 * Temperature (*F) * Precipitation Totals (Inches) Mean number of days Temperatures Means Extremes Snow, Ice Pellets (b) 1 1 Max. Min. 1 o ! I 1 Î Ifll 1 II 1 ]] 1 1 1 1 JIf 1 lî 1 l1 llllU1 (a) 30 30 30 30 30 20 30 30 17 17 JAN. 34.1 18.8 2 6 .5 56 1953 -36 1950 1164 2 .61 1 .4 4 1969 1 0 .5 2 9.9 1943 1 0.5 1954 8 0 9 29 3 JAN. FEB. 4 2 .3 2 3 .6 3 3 .0 64 1968+ -30 1950 891 1.85 1.15 1963 8.6 2 5 .0 1936 8 .0 1936 6 0 2 25 1 FEB. MAR. 49.9 26.0 38.0 78 1952 -1 0 1955 847 1.72 .9 2 1961 3 .8 19.0 1932 15.0 1932 6 0 1 26 * MAR. APR. 6 1 .3 3 2 .5 4 6 .9 90 1952 17 1966+ 556 1.72 1.53 1970 .4 6 .7 1929 4 .0 1929 6 0 15 0 A m . MAY 7 0 .7 3 9 .3 5 5 .0 97 1966 20 1954 311 1.86 1 .9 5 1957 I T 1943 I 1943 5 0 4 0 MAY JUNE 7 6 .6 4 5 .7 6 1 .2 100 1941 30 1951 134 2 .1 7 2 .2 3 1964 0 0 ------0 ------6 3 0 * 0 JUNE JULY 8 7 .8 4 9 .2 68.5 109 1953 35 1962 32 .8 4 1 .2 8 1970 0 0 0 2 15 0 0 0 JULY AUG. 8 6 .3 4 8 .1 6 7 .2 107 1961 32 1965 46 1 .1 0 2 .1 7 1966 0 0 — — - — 0 — — — — 3 13 0 * 0 AUG. SEP. 76.2 42.1 59.2 106 1950 24 1970+ 197 1.41 1.21 1954 IT 1934+ T 1934+ 4 3 0 2 0 SEP. OCT. 6 1 .2 3 5 .0 4 8 .1 89 1945 18 1949 519 2.11 1.10 1942 .4 5 .7 1930 5 .2 1930 6 0 0 11 0 OCT. NOV. 4 4 .3 2 8 .3 3 6 .3 65 1948 -1 3 1959 864 2 .6 3 1.51 1961 2 .5 13.5 1946 6 .0 1946 8 0 1 22 4 NOV. DEC. 3 6.4 2 3 .7 30.1 59 1965 -25 1968 1083 2 .5 0 1.41 1964 7 .8 16.5 1937 7 .0 1937 8 0 7 28 * DEC. JULY JAN. JUNE JAN. MAR. Year 6 0 .6 3 4 .4 47.5 109 1953 -3 6 1950 6644 2 2 .5 2 2-23 1964 3 4 .0 29.9 1943 15.0 1932 68 34 20 162 4 Year (a) Average length of record, years. + Also on e a r lie r d a tes, months, or y ea r s. T Trao#, am amount too small to measure * Lees than one half. *• Base 65*F (b ) Snow fall data in co m p lete, mean and max monthly data for 1928-1945. Greatest daily snow is for period 1928-1957 with some months data m issin g . 12 Mean annual precipitation, mostly rain, is 22. 5 inches. Maximum precipitation occurs during November, December, and January with a secondary peak in June. Mean yearly snowfall is less than 50 inches with January having the greatest snowfall; however, some rain occurs during January of almost every year. Some high peaks receive in excess of 300 inches snowfall per year. July and August are the driest months averaging 0. 84 and 1.10 inches of rain, respectively. The average annual temperature is 47. 5° F. January is the coldest month averaging 2 6. 5® F. Subzero temperatures are uncommon. The warmest temperatures are recorded during July and August with monthly means of 68. 5® F and 67,2® F, respectively. July averages 15 days of maximum temperatures above 90® F with temper atures frequently exceeding 100® F. The summer of 1973 was one of the driest on record. Mean temperatures of 70. 0 and 69. 5® during July and August were slightly above normal. There was no precipitation in July, and only 0. 14 inches during August. The 1973-74 winter was wetter than normal. November had 4. 42 inches of precipitation. Early January rains bared south facing slopes below the 4, 000 foot level. Those slopes were relatively free of snow for the remainder of the winter. 13 V egetation Floristic composition in the Thompson Falls region reflects the Pacific Coast Climatic influence. Species common to the west coast such as western red cedar (Thuja plicata), western hemlock (Tsuga heterophylla), mountain hemlock (T. mertensiana), grand fir (Abies grandis), western white pine (Pinus monticola), and western yew (Taxus brevifolia), occur in the study area. The local flora is listed in Appendix A. The following description of vegetation is based on habitat type inventories compiled for resource planning purposes by the U. S. Forest Service. Portions of Deerhorn, Big Hole, and Cube Iron- Silcox planning units fall within the confines of the study area and their habitat groups are delineated on topographic maps (on file. Plains and Thompson Falls Ranger District Headquarters). I constructed the vegetational composition map for the sheep range (Fig. 3) from those planning unit maps. The 10 broad habitat groups represented on the study area are described below. Each group is comprised of several habitat types with sim ilar climax tree species but with variation in dominant understory species. I. Ponderosa pine (Pinus ponderosa) The ponderosa pine habitat series includes the following climax plant associations: 1) ponderosa pine/ Fig. 3. Vegetation composition map for study area. N um erals 1-10 correspond with habitat series I-X in text of thesis. Vertical lines indicate cliffy areas. North is towards top of page. Scale: 1 inch = 2.0 m iles. 15 bluebunch wheatgrass (Agropyron spicatum); 2) ponderosa pine/Idaho fescue (Festuca idahoensls); 3) ponderosa pine/ bitterbrush (Purshia tridentata); 4) ponderosa pine/snow- berry (Symphorycarpos albus); and 5) ponderosa pine/ pinegrass (Calamagrostis rubes cens). This habitat group is confined to elevations below 3, 000 feet and restricted in distribution. Valley bottoms, well-drained benches and hot dry aspects characterize the distribution of this series. At upper range limits on relatively dry exposures, Idaho fescue is found; common snowberry occurs on more mesic sites. At the lower elevations on the most xeric sites, bluebunch wheatgrass, arrowleaf balsam root (Balsam orhiza sagittata), and bitter brush are the dominant understory species. Ponderosa pine is generally a serai species being gradually replaced by Douglas-fir (Pseudotsuga menziesii), the climax dominant. True climax ponderosa pine communities are extremely limited on the study area. II. Douglas-fir/Grass This group consists of two climax associations, Douglas-fir/bluebunch wheatgrass and Douglas-fir/ pinegrass. Near 2, 800-foot elevation on warm dry aspects, bluebunch wheatgrass is the common associate. At 16 mid-elevations, approaching 5, 600 feet on similar aspects, pinegrass is found. This habitat type series has a limited, widely dispersed distribution on the study area. III. Douglas “fir/Shrub The Douglas-fir shrub habitat types occur over much of the area, growing under a wide range of microclimatic conditions. This group's elevational range lies between 2, 800 feet along the Thompson River to approximately 6, 000 feet along southerly exposures facing the Clark's Fork River, Mid-elevations, benches and warm dry slopes characterize this series. The common serai associate, ponderosa pine, is replaced above 5, 600 feet on moist northerly exposures by western larch (Larix occidentalis), and lodgepole pine (Pinus contorta). Climax association in this group are: 1) Douglas-fir/thin leaved huckleberry (Vacciniiun membranaceum); 2) Douglas-fir/kinnikinnick (Arctostaphylos uva-ursi); 3) Douglas-fir/snowberry; and 4) Douglas-fir/ninebark (Physocarpus malvaceus). On mesic sites near the upper elevational limits of this group, beargrass (Xerophyllum tenax) and thin leaved huckleberry dominate the understory. On moderately mesic sites, such as ravines on southerly exposures, ninebark and ocean spray (Holodiscus discolor) are common. The Douglas-fir 17 snowberry association is common along the Thompson River at lower elevations, while kinnikinnick is common on slightly cooler and drier sites. IV, Clintonia (Clintonia uniflora) Under this heading, clintonia (queenscup) is the common understory species found in association with grand fir, western red cedar, western hemlock, and subalpine fir (Abies lasiocarpa). This group is found along stream bottoms and on moist north-facing slopes. Eleva tional range lim its are between 2, 800 and 5, 800 feet. Grand fir is the climax dominant on low north aspects. Western larch and Douglas-fir are the major serai tree species on this habitat type. Many browse species, including redstem ceanothus (Ceanothus sanguineus) do well on disturbed sites within this habitat type. The western red cedar habitat, found along major stream courses, is generally restricted to below 4, 800 feet. Serai tree species on this type include western larch, grand fir, subalpine fir, western white pine and Engelmann spruce (Picea engelmannii). Slightly above the grand fir type, the subalpine fir climax predominates. Its elevational amplitude is exceeded above approximately 5, 200 feet on north slopes and 6, 000 feet on south aspects. 18 Confined to north aspects above 5,200 feet, with precipitation requirements in excess of 40 inches annually, the mountain hemlock community is extremely limited on the study area. V. Menziesia (Menziesia ferruginea) Cool moist slopes, generally on northern exposures, at mid- to high elevations (4, 500-6, 000 feet) typify this group. Menziesia is the dominant understory species normally found in association with subalpine fir or mountain hemlock. VI. Dry Beargrass Included in this group are the Douglas-fir/beargrass, grand fir/beargrass, and subalpine fir/beargrass habitat types. These are generally found at mid- to high elevations (5, 000-6, 000 feet) on relatively warm dry exposures. Much of the higher elevations in the south eastern portions of the study area fall within this group. VII. High Forested Ridge Subalpine fir and mountain hemlock are the dominant species in this grouping. These habitat types occupy cool, dry, flat ridges at higher elevations up to nearly 6, 000 feet. Grouse whortleberry (Vaccinium scoparium) and beargrass are common associates. 19 VIII. Devil's Club (Oplopanax horrldum) Occurring at mid-elevations in cool stream bottoms, devil's club is the dominant under story for this group. Major dominant tree species are western red cedar, western hemlock, and subalpine fir. Habitats of this nature are confined to portions of the West Fork of the Thompson River, Anne Creek, Munson Creek, and Spring C reek. IX. Subalpine This group is associated with ridge tops above 6, 000 feet. Subalpine fir and whitebark pine occur together as climax co-dominants. Beargrass and huckleberry are typical associates. A few small areas on Sundance Ridge fall within this category. X. S cree This group is divisible into the Douglas-fir-ponderosa pine/scree habitat type at approximately 5, 500 feet and below, and the subalpine grass or snow slide type at elevations above 5, 500 feet. Edaphic factors have controlling influence over the vegetation on these types. The soil mantle is thin and texture is coarse. The sub strata is fragile, subject to slumping and colluvial processes. Southwest exposures on Sundance Ridge are 20 characterized by snowslide chutes with beargrass as the dominant vegetation. Most of the Thompson River corridor and nearly all of the southerly aspects over looking the Clark's Fork are classified under the Douglas- fir-ponderosa pine/scree habitat type. Shrubs are the dominant life forms on most of this type. Important species include mountain maple (Acer glabrum), Oregon grape (Berberis repens), evergreen ceanothus (Ceanothus velutinus), mockorange (Philadelphus lewisii), bitter cherry (Prunus emarginata), bitterbrush, squaw current (Ribes cereum), rose (Rosa woodsii), serviceberry (Amelanchier alnifolia), and ocean spray. Other vegetational communities occur on the study area. Willow (Salix spp. ), redoiser dogwood (Cornus stolonifera), black cottonwood (Populus trichocarpa), hawthorn (Crataegus douglasii), alder (Alnus spp. ), and clematis (Clematis columbiana) are common riparian species. Small stands of quaking aspen (Populus tremuloides) occur on moist depressions, generally at the base of slide-rock areas. A variety of annuals and other herbaceous plants are common along the low dry slopes overlooking the Clark's Fork. During spring and early summer, these species assume seasonal dominance according to their respective phenologies. CHAPTER III MATERIALS AND METHODS Trapping Trapping activities were conducted in two phases, June-July 1973 and December-January 1973-74. Four man-made salt licks and three natural mineral licks (Fig. 4) were located. I installed clover traps (Fig. 5) provided by the Montana Fish and Game Department at three salt licks that were accessible and received heavy sheep use. In addition, one large corral-type trap, equipped with manually operated drop-gate, was constructed at traps it e B. Winter trapping was confined to trap sit es C and D. All traps were baited with 50- pound blocks of salt (NaCl 99 percent, inert matter 1 percent) during summer trapping. Alfalfa-grass hay, topped with a livestock sweetfeed mixture of rolled oats, barley, and molasses served as bait at winter trapsites. Traps were inspected twice daily, once in midmorning and again in late afternoon, to insure that the animals did not occupy traps more than 16 hours. Many hours were spent at salt licks noting times of arrival and departure, time spent at licks, numbers, ages and sexes of animals, responses to traps, and general sheep behavior. 21 Fig. 4. Topographic map of southern portion of sheep range. Letters A, B, C, and D over open circles show location of trapsites (continued on next page). L shows natural mineral licks. Solid circles represent cens using points. f / # - i V;)*>r, '/ ; ) i , Y ' é ^ . ' ( ( ( (^'\'^, vt •■ fw » i ü i \ Y > Y â S y. Fig. 4 (continued). A y Fig. 5. Photographs of bighorn sheep showing: A. Radio collared ewe and type of trap used. B. Adult with rope collar (upper left); yearling ram, 16 months of age (lower right). C. 45-month-old ram (3/4-curl status). D. Same ram as in Photo C. 25 Tranquilizing drugs were not used. Trapped bighorns were manhandled and their legs secured in a fashion similar to that of tying up a calf. Each animal was marked with a color-coded, rope-flagging collar sim ilar to those described by Craighead et al. (1969) (Fig. 5B). Each collar consisted of three flags in combination with white rope for males and yellow rope for females. Every collar included either a red or black pendant, each numbered differently with white numerals, thus facilitating individual identification at close range. The three flags identified animals at longer distances. Inside circumferences of collars were 23 inches for ewes and 25 for rams. Live weights were obtained with the aid of a Chat ill on type-160 spring scale. Each animal was examined for ectoparasites and general body condition was noted. On 21 June 1973, one adult ewe was equipped with a radio transmitter collar (Fig. 5A) designed by Varney. The transmitter operated on an intermittent pulse rate of 19 pulses per minute. A small receiver, also designed by Varney (1971), with both loop and whip antennas was used to locate the radioed ewe. All location ’’fixes” were obtained from ground triangulation and plotted on U. S. Geological Survey topographic maps (1:24,000). In addition to transmitter fixes, several visual contacts were made of the radioed sheep. The trans mitter was functional through March 1974. Marked sheep provided data on home range, seasonal 26 movements, short-term movements, group fidelity, population numbers, lamb survivorship, and herd structure. Exact locations of marked animals were determined from U. S. Geological Survey topographic maps (1:24,000), and then transferred to special U.S. Forest Service topographic maps (1:63, 360). Group Fidelity Group cohesion or constancy as explained by Knight (1970) and Erickson (1972) was tested, using the method described by Cole (1949). The degree of association between any two marked bighorns was calculated for each season of the year. The probability of two sheep once observed together being associated again within each seasonal period was given by mean values for all coefficients of association, A perfect association between any two marked bighorns was shown by a coefficient of association value of 1. 00. Winter Centers of Activity The extent of movements for marked bighorns, during winter, was determined using methods described by Knight (1970) and Erickson (1972). The centers of activity for individually tagged animals were defined on topographic maps using a grid overlay system as explained by Hayne (1949). Centers of activity were used with Harrison's (1958) formula (SD - V Z, /N) to calculate the standard diameter (SD) for each marked animal. D is twice the 27 distance from the center of activity to each relocation, and N is the total number of relocations. The standard diameter represents the diameter of a circle with the center of activity as its center, and which contains 68.26 percent of all relocations of an animal during the period considered. P a r a site s During the period April-December 1973, 100 fecal pellet groups were collected from animals of known age and sex. These animals were observed defecating and the feces were collected immediately. An additional 100 fecal samples were collected from animals of unknown age and sex during the first 2 weeks of April 1974. All samples were sent to the Veterinary Research Laboratory, Montana State University, Bozeman, and analyzed for presence of lungworm larvae, Protostrongylus rushi and P. stilesi, using the Baermann technique. Respiratory tracts from four hunter-shot rams, one adult ewe and one lamb (both road kills, April 1974) were immediately frozen and sent to the Veterinary Research Laboratory for examination. Food Habits During early summer 1973, a limited number of feeding sites were examined. Vegetational composition for each feeding site was sampled by five 50-foot line intercept transects laid out parallel 28 to each other at 10-foot intervals along the slope of the terrain. Plant species along each transect were examined for indications of sheep use. Number of bites were recorded for each species. This method was soon abandoned as it was extremely time consuming, and interfered with the trapping and marking operations. Most of the food habit data were collected by observing sheep at close range and recording food items taken. Rumen samples from four hunter- harvested rams taken in the fall 1973, plus one adult ewe and one lamb struck by automobiles during April 1974 were examined. C ensusing Population estimates were derived from the Lincoln index method (Southwood 1966). Several censuses were made during winter and spring 1974. Data for the Lincoln index method were collected from a set of predetermined points located along State Highway 200 between Weeks ville Creek and a point approximately 1. 5 miles west of the Thompson River (Fig. 4). Approximately 10 minutes were spent at each of these points examining the slopes with binoculars and spotting scope. All censusing along this route was done in late afternoon as that was the time of greatest sheep activity. In addition to the ground censusing, one helicopter survey covering the same area was flown on 16 April 1974. 29 Ob s e rvat i ons Observations were aided by the use of 7x35 mm binoculars and a 15-60x variable spotting scope. Observations were recorded on special form sheets (Fig, 6). Rams were aged in the field by annulation counts (Geist 1966). Ewes were classified as yearlings or adults during summer. No attempt was made to ascertain the sex of lambs until late fall, at which time males were distinguishable from females by larger and distinctly shaped horns. During summer and early fall, frequent exploratory trips were made on foot into the roadless areas in an effort to delineate summer range. Areas suspected of sheep use were examined for the animals or their signs, i. e. , tracks, bed sites, and pellet groups Fig. 6. Datum collection form sheet. 30 L ocation Date T im e Weather Conditions Cloud cover: 100% 75% 50% 25% 0 Fog Wind velocity; 0-5 mph 6-10 mph 11-15 mph 16-20 mph 20 mph Wind direction: N S K W NE NW SE s w Precipitation: Rain Snow H ail Temperature: A spect: N S E W NW SE SW Slope: 0 - 5^ 6-10 11-15°, 16-20°, 21-25°, 26-30“, 31-35°, 36-40°, 4 1 -4 5 “, 45 Terrain: Talus Broken ridge Rock outcrops V egetation G rassland B rushy Woodland F o rested Type G r a sses - Shrubs - T r e e s - No. of Groups Group Designation: Ewe Ram M ixed Total No. Sheep No. cT No. ? Lambs of '73 Lambs of '74 1-yr. -old d 2 -yr. -old d 3 - y r .- o ld d 4 - y r .- o ld d 5-yr. -old d 6-yr. -old d 7 -yr. -old d 8 -yr. -old d 9 - y r .- o ld d 10-yr. -old d Activity: No. feeding No. bedded Movement : Direction Speed Nearest Source of Water Nearest Cover CHAPTER IV RESULTS Trapping Between 18 June and 22 July 1973, I captured, marked, and released 20 bighorns (10 adult ewes, 2 yearling ewes, 4 yearling males, 2 female lambs, 2 male lambs) at trapsites A and G (Fig. 4, Table 2). Trapping and handling resulted in a few minor injuries. Scratches and abrasions around the head and neck were noted on four of the sheep. One female lamb (No. 174) lost the left horn sheath and appeared dazed when released. She walked slowly into a nearby cliff area, paying no attention to the calls of her dam. The ewe joined the lamb which suckled briefly, then both lay down. I observed them for over an hour before they departed. The lamb was subsequently sighted on several occasions during winter and spring of 1973-1974 and appeared in good health. Bighorns proved tolerant of human presence at salt licks, A sm all-scale logging operation was conducted, near traps it e A, during summer 1973. One of the log landings was positioned immediately adjacent to the lick and trap. Sheep frequently milled about the machinery. Logger’s activities did not interrupt the animals' 31 TABLE 2. Age, sex, live weight, location and date of capture, and marking system for 20 bighorn sheep captured during summer 1973 Collar Ear tags Capture Classification Weig Pendant no. Flagging L R Traps it e Date Sex Age and color 411r WWW/y - - B 6/18 ? 4 - Radio Collar Blue & Ylw - - A 6/21 ? 6 - 410r B B B /r - - A 6/22 ? 1 - 412r WBW/y - - B 6/24 ? 5 - 413r BBB/w AlOOl A1002 B 6/26 d* 1 110 414r BW B/y A1004 A1003 B 6/26 ? 3 140 415r BYB/w A1005 A1006 A 6/30 d* 1 125 416r BY B/y A1007 A1008 A 6/30 ? 1 105 42 Or WYW/y A1009 AlOlO B 7/1 ? 5 145 42 7r WBW/w A lO ll A1012 A 7/1 d 1 110 42 8r YWY/y A lo is A1014 A 7/4 ? 5 137 toCO TABLE 2. (continued) Collar Ear tags Capture Classification Pendant no. Weight and color Flagging L R Traps it e Date Sex Age 446r GGG/w A1015 A1016 A 7/4 cT Lamb 30 435r WWW/w A1017 A1018 A 7/6 d 1 130 445r GGG/y A1020 A1019 A 7/10 ? Lamb 40 447r RRR/y A1021 A1022 A 7/10 ? 4 160 436r WYW/w A1023 A1024 A 7/11 d Lamb 47 44 9r GRG/y A1025 A1026 A 7/11 Î 5 145 174b RGR/y A1027 A1028 A 7/14 ? Lamb 55 213b RWR/y A1029 A1030 A 7/22 $ 3 130 231b GWG/y A1031 A1032 A 7/22 ? 5 150 r = red pendant w = white rope B = Black flag Y = Yellow flag b = black pendant y = yellow rope W = White flag G = Green flag R = Red flag CO 00 34 visitations to the lick, and probably habituated the sheep to humans and machinery. On seven occasions sheep entered traps, while I was within 50 yards. Frequently, the animals peered in at the salt block while walking around the trap. Individual bighorns tested the trap by nibbling and pulling at the netting and tie ropes, and pawing around the edges of the framework. Under those circumstances, I often approached the lick, very slowly, and moved the salt to a position outside the trap. Sheep generally watched this procedure from a short distance, and returned immediately once I moved away. After the animals licked the salt for a few minutes, the process was reversed by replacing the block within the trap. This procedure resulted in the capture of four bighorns. Salt Lick Utilization Activity at salt licks and trapping success were directly related (Figs. 7 and 8). Although traps were operated 19 days in June and 2 5 days in July, 75 percent of all captures occurred between 24 June and 14 July. During that period bighorns made daily visits to lick sites. Maximum activity at licks occurred between 1:00 and 5:00 p. m. ; 17 of the 20 captures were made during afternoon inspections of traps. In single file, groups of sheep frequently approached salt licks at a steady, moderately fast walk. Departures were of a more gradual Fig. 7. Chronological distribution of bighorn captures Fig. 8. Chronological distribution of bighorn salt lick utilization. MEAN NUMBER SHEEP OBSERVED PER DAY AT LICKS % BIGHORNS CAPTURED —^ KJ ro W w viv cn O O i o Ln O Oi è Vi O i____L I J-J Ln a CO Cn 36 nature. After approximately 2 or 3 hours at licks, individuals and sm all groups (two to three animals) slowly dispersed over the slopes and evening feeding began. Ewe groups, including ewes of all ages, yearling males, and lambs congregated at licks in the afternoon. Occasionally, I observed young rams (2-3 years old) using licks during midmorning. None were seen at those areas during late afternoon. After mid-July, lick utilization diminished rapidly as sheep dispersed onto summer range. Lick visitations were sporadic throughout the remainder of the year. At irregular intervals during fall and winter, I observed bighorns near salt licks, but examination of those licks generally indicated that they were not used. During mid- November and early January, I saw sheep pawing snow from around salt blocks and licking salt. Trapping bighorns during winter was unsuccessful. Although two traps were set in an area frequented almost daily by sheep (trap- sites C and D), the animals completely ignored the bait. Snow accumulation was minimal in December, and early January rains cleared the trapping area of all snow. This resulted in total avail ability of natural forage which reduced the attractiveness of artificial b ait. 37 C o lla rs Three-flag collars proved adequate for marking the small number of captured sheep. Under proper light conditions, pendant numbers were readable at approximately 0.25 mile. Depending on orientation of the animal and light conditions, flag colors were discernible for approximately 1 mile. Certain flag colors were more difficult to recognize than others. White and yellow were difficult to differentiate at long distances. Flag combinations of bright red, lime green, and white were easiest to identify at long range. The collars were durable. During April 1974, I saw 19 of the 20 marked bighorns. Their collars were intact and in good condition. Some difficulties were experienced in fitting lambs with collars which would accommodate their rapidly increasing neck sizes. Surgical tubing (0.25 inch) was used to prevent collars from slipping over lambs' heads. Ideally, the rubber tubing was to rot away in a few months, resulting in collar expansion to the recommended adult size. By that time, horn growth would prevent collars slipping over heads. Collars on two lambs. Nos. 446 and 445, expanded to full size by December 1973. However, collars on Nos. 436 and 174 did not expand until late April 1974. Collars on those two lambs were snug and caused some discomfort to the animals. They shook their heads from side to side in apparent attempts to remove the collars. The other collared lambs did not behave in this manner. 38 C ondition Weights for 16 of the trapped sheep are included in Table 2. One adult ewe and one female lamb were killed by vehicles during April 1974. Their live weights were 155 and 68 pounds, respectively. The ewe was weighed within 2 hours of death, while the lamb was not found for 2 days after its death. Average weights, taken in early summer, for lambs, yearling ewes, yearling males, and adult ewes were 43, 105, 119, and 145 pounds, respectively. One 4-year-old ram, shot on 3 November 1973, weighed 270 pounds live weight. Hog- dressed weight for this individual was 200 pounds, a weight loss of 26 percent. Ages and hog-dressed weights for three other hunter- harvested rams were 3-year-old, 170 pounds; 4-year-old, 175 pounds; and 6-year-old, 195 pounds. Calculated live weights for those rams were 230, 237, and 264 pounds, respectively. All four hunter-shot rams, examined during fall 1973, appeared in good health. Subcutaneous fat layers were thick, measur ing 1 inch in some places. Kidneys were enveloped by large volumes of fat, and fatty tissue was interspersed throughout abdominal mesenteries. D em ography Population segments. The bighorn population consisted of two herd segments. One segment ranged the precipitous terrain along 39 the north side of the Clarkes Fork River, between Weeksville Creek and the Thompson River (henceforth referred to as the Clark's Fork Unit). The other segment occupied the rocky canyon walls along the west side of the Thompson River, from its mouth, north to Deerhorn Mountain (henceforth referred to as the Thompson River Unit). Fig. 9 shows the post-transplant dispersal patterns and present-day ranges of the respective herd segments. Interchange between the two segments was minimal, being restricted to rams which crossed the Thompson River. Ewe groups maintained their respective home ranges on either side of the Thompson River and were not known to cross. Several marked sheep visited the west face of Koo-Koo-Sint Ridge, overlooking the Thompson River from its east bank. Five collared sheep were seen a total of 2 7 times on that west face. Only one of those bighorns, ram No. 413, was observed on the west side. That individual was seen with ewes on the west side on three occasions during September 1973. He was later sighted several times back on the east side. Ewes 414 and 449 wintered on the west face of Koo-Koo-Sint Ridge. They were never observed on the west side where ewes from the Thompson River Unit were wintering. On 20 February, the two collared ewes departed from their wintering area and moved east towards Weeksville Creek. Population estim ates. Population estimates derived from the Fig. 9. Transplant sites (T) and post-transplant dispersal p attern s. 40 41 Lincoln index method were restricted to the Clark's Fork Unit, as animals from the Thompson River Unit were not marked. From 6 February to 16 April, nine censuses were taken along the route shown in Fig. 4 and revealed an estimated population between 142 and 155 animals for the Clark's Fork Unit, including all age and sex classes. A certain degree of bias was inherent in the estimate. Rams, 2 years of age and older, were not marked; however, they were included in the sample base for each census. This bias was corrected for in the following manner. Rams, 2 years old and older, and ewe groups (including ewes of all ages, lambs, and yearling males) were treated as two discrete populations. The above qualification was assumed valid because rams and ewe groups were segregated throughout most of the year. The ram element was, therefore, deleted from each of the census samples, leaving the ewe-group population to be computed separately. The ewe-group population was estimated at 12 5 individuals, The ram component was then computed using fall ratios of 31 rams per 100 in the ewe-group classification; 39 rams were estimated for the Clark's Fork Unit. Once these adjustments were made, the total population estimate for the Clark's Fork Unit became 164 animals. Best count figures were relied upon for estimating population numbers of the Thompson River Unit; 59 bighorns were tallied on the afternoon of 17 April 1974. All fell within the ewe-group category. Using the same ratio as the Clark's Fork Unit, the ram component 42 for the Thompson River Unit was calculated at 18, bringing the total estimate to 77. The combined estimate for both units was 241 sheep. Age-sex composition. Age and sex composition and ratios are listed in Table 3, Observed ratios of ewes to lambs, yearlings, and rams are given as they occurred in the field. Calculated ratios were derived with the following assumptions and methodology. Yearling ewes became increasingly difficult to differentiate from adult ewes during fall and winter. Yearling males were readily distinguished from all other age and sex classes. The number of yearling ewes equalled the number of yearling males for any 1-month period. Deducting the number of yearling ewes from the total number of ewes left only those females 2 years of age and older. This last figure was used to arrive at calculated ratios. Age structure of the sheep population weighed heavily towards the younger age classes as indicated from horn annulation counts of 173 observations of the same rams during the fall rut and spring concentration period (Table 4). I never saw a ram older than 8 years, and males 7 and 8 years old constituted a small percentage of the ram population. However, due to their behavior and habitat preference, older rams were less observable than younger ones, thus creating a bias in number towards younger rams. TABLE 3. Sex and age classification of bighorn sheep by month, 15 May 1973 to 15 May 1974 Observed Calculated Sample Adult Yearling Month Adult Yearling Lambs no. per 100 ewes no. per 100 ewes size m ales m ales fem ales fem ales lambs : yearlings : rams lambs : yearlings May^ 15 8 6 1 16 133 June 111 17 15 37 11 31 84 70 67 94 91 July 160 6 20 67 18 49 73 57 31 83 68 Aug. 37 3 1 16 1 16 100 13 24 100 14 Sept. 104 15 47 7 35 75 47 28 90 77 Oct. 116 26 8 38 10 34 90 47 71 94 44 Nov. 159 21 10 65 8 55 85 28 43 92 33 Dec. 150 18 18 62 3 49 79 34 55 96 88 Jan. 96 6 5 42 8 35 83 31 22 83 22 Feb. 342 18 40 141 14 129 92 38 37 95 40 March 236 31 11 104 8 82 79 18 38 90 24 April 302 16 19 146 13 108 76 22 22 80 28 May^ 24 15 6 2 ic Total 1,852 185 168 771 103 625 16-31 May. b 1-15 May. ^Lamb of 1974. CO 44 TABLE 4. Age classification of free roaming bighorn rams by annulation counts Num ber of P ercen t of Age in years individuals totals 1 72 41. 6 2 31 17. 9 3 31 17. 9 4 15 8. 7 5 16 9.2 6 6 3. 5 7 1 0. 6 8 1 0. 6 45 Survivorship. Mortality during winter, 1973-1974, was apparently low. I did not discover any carcasses during spring exploration of wintering areas. During April and May, 1974, 19 of the 20 collared sheep were resighted, indicating negligible mortality within the sex and age groups represented by marked animals. Ewe 420 was last sighted on 2 8 November, and presumably died during winter. Lamb survival through their first winter was extremely high (Fig. 10). This was further substantiated by the fact that all four lambs captured during summer 1973 were observed alive in April and May, 1974. Group size and composition. Between 1 April 1973 and 24 May 1974, I classified 311 bighorn sheep groups. Mean group sizes for ewe, ewe-lamb, yearling, ram, and mixed groups were 2.0, 7.8, 2.1, 3. 7, and 7. 1, respectively. The average group size for all categories was 5. 3. Groups varied in number from single animals to bands of 40 (Table 5). Seasonal variation in mean group sizes for each age-sex category are listed in Table 6. Of the four groups in the 31-40 category, one was a mixed group during fall, and three were ewe-lamb groups during spring. The largest ram band, observed on 23 June consisted of 15 animals, eight of which had horns with 3/4 curl or greater. Eleven of the 2 9 single Fig. 10. Monthly ewe:lamb ratios: Observed # " ' # Calculated ♦ ...... ♦ NUMBER LAMBS PER 100 EWES NJ u> Cn o VJ oo o O o O o o o o o cn w O- 'O > 9^ 47 TABLE 5. Group size frequency distribution from observation of 311 bighorn groups Group Size 1 2-10 11-20 21-30 31-40 No. of observations 29 241 31 6 4 Percent of total 9 78 10 2 1 48 TABLE 6. Seasonal change in mean group size for each of the age-sex categories C ategory Summer Fall W int er Spring Ewe 2. 5 1 .0 3. 5 1. 1 Ewe-lamb 11.0 5. 8 7.2 7 .0 Yearling 1.4 2. 0 3 .0 Ram 2. 5 3. 0 2 .1 7.2 M ixed 4. 5 11.2 9. 1 3 .6 49 animals were rams, nine were yearlings, and nine were ewes. Ram groups were largest during spring and early fall (October), while ewe- lamb groups were largest in summer and late winter. Young rams began disassociating from ewe groups at an early age. Approximately 30 percent of the yearling rams sighted during winter, spring, and summer were associating with ram bands. On 11 May 1974, I observed ram lamb 446 traveling with nine other rams, ranging in age from 1 to 6 years. Two- and 3-year-old males were almost always observed in ram groups (Fig. 11). The majority of yearling males remained with ewe groups through the rut. After the rut, many of those yearlings left the rutting areas with mature rams. Group fidelity. From repeated resightings of marked bighorns, it became apparent that interchange of individuals between groups was common. Tagged animals observed together were often seen separately with different tagged animals on other days. On several occasions, I watched groups of sheep, containing marked individuals, converge and eventually separate into herds with different combinations of collared animals. Mixing of marked sheep was especially noticeable at salt licks. Group cohesion was tested using the method described by Cole (1949). For winter, spring, and summer over 75 percent of the coefficients calculated were 0. 50 or less, indicating little attraction Fig. 11. Dissociation of young rams from ewe groups first 5 years of age. PERCENT OCC UR RENCE Ram Groups Ewe Groups o XI Cn tsj K) Cn O o en O Cn Cn O O [ e n O 51 between any two individuals intraseasonally (Table 7). Certain individual bighorns showed high degrees of association for one season, while they had low coefficient values or showed no degree of associ ation during other seasons. Of six pairs of animals with perfect associations during one season, only one pair was observed together during the preceding or following season. Five of the pairs were not seen together during any other season. The small number of associ ations recorded during fall (12) was partly responsible for the relatively high mean coefficient of association. That is, two animals seen together once during a season, were either not resighted or were together on each subsequent observation. The mean coefficient of association for the entire year was 0.27, indicating that perfect associations were not necessarily inter seasonal. Distribution and Movements Major, seasonal, key-use areas are delineated in Fig. 12. Figs. 13-17 demonstrate annual movements typical of bighorn sheep in the Thompson Falls area. Table 8 provides dates and approximate transmitter locations for the instrumented bighorn ewe. Dates and locations for lambs 446 and 436 are listed in Appendix B, Winter range. The majority of bighorns wintered on south to southeast exposures at elevations from 3, 500 to 4, 500 feet. Fluctu ating snow depths determined the upper limits of winter distribution. TABLE 7. Mean seasonal coefficients of association for marked bighorns and percentages in five frequency classes, June 1973-May 1974 Mean coefficient Number of Frequency Classes Season of association associations 0. 0 -0 .5 0 0 .2 6 -0 . 50 0. 51-0. 75 0. 76-0. 99 1.00 Summer 1973 .45 32 0 78 22 0 0 F all 1973 .75 12 0 33 25 0 42 Winter 1974 .37 53 26 64 4 2 4 Spring 1974 .45 72 8 76 3 1 2 Ü1 DO Fig. 12. Seasonal key use areas: Outline of winter range Spring concentration areas Summer locations # Lambing grounds ■ I /-M t . ' 'K^. j\«i '1 ^ Headley V 19 r :A . ^ •V - .A- 1 - ;.- - - - \) ^ ' ' # ' ^ j r I / ' / Priscilla ’^h'tuni'Uf^h les 1---^ leos^oo^ I r r o itM ’iJLffi, ■ Ç i Hijr^ti/mo^n D iickhniti -' 29 //' Round lop U/ ^ % 6«S6' : Mtn \ ''»/ m '3< ,N i MTS->c',jnVss“'-j' r Copper tCmgj arc MOic m 2 ± ! k ' 6 • If"^ - ^ 3 Fig. 13. Summer movements of radio-equipped bighorn ewe. Numerals represent sequential transmitter "fixes." Solid circles show locations of visual sightings. (See Table 8. ) w m m g s m i /'3 (I , , ^ . .- . \ ! y J:,-, :\ 5 !' ; 4 ' % j , :■■■ / _ . ■ , - ; / ' ' ^ / ^ 1'.— i^s.'* I / \ I ''/'' ' '' ,.• ; ^ // • r 1 -i ~r f- T*“^-' ' ,yy ^ / K#*##' ^sm f" t / A ' J - :-// ##'y i u j y a . v M _ j ■; I - a s a s i i ï V X ' t I r ./% . _ ^ ') . ■; ,7J -^t jf ^ ./ • ». #:### / ,/ y ' œ a f i i i i ^ : c i ; # ; . r6 '.•/'/■ /,% ■, V// Fig. 14. Annual pattern of movements for male lamb No. 446. (See Appendix B for dates of resightings. ) O' „ 1 ,0 ( >--t-ViVi ' ÎÜ V!'V iï-m ' wcy,nv v'i Doerhoi Mtr “ w % 1 t f e r T T T i T ^ ^ \ll' VI fl/ . , .,/ Priscilla irrn , lrmii Ai'iiJ Hdntymo6\ Af/iriltf-. lr-“ ' ^C%/ _j_ S 1 :i ■ ■''; Roundup” .&V ■-/ , # v: Mtn g X/ i)s\B # ; ; / ! : ! / V I/o HOlf -V I % NS.* Fig, 15, Annual pattern of movements for male lamb No, 436, (See Appendix B for dates of resightings. ) V I '/ I -/ /' ^ V J - t /' V ! , I _,. •■ -;,v V; / y /■ I iS V.* ' ■■ ■' . :'» “ • —t i#— - — i S liif'P■ I Ii’.ri, .,m^,m^u^ & f 1 I , , 7 ' n III '>!■ : nC !flr5M K ^\ ZT :! ■ I \ - I I-"I'll I iT,'"* I'/'iA/J 7 !' Tf h* Mill hiu Itt(~ I. -r X . V,i'7 • ::%###%: '* \ H' ,— ’ / Yv V V ■■■%< . 3 ^ ■-.V I kI V:- ! / 4N ,‘- L' " y-, '| _/' 1^' < / | V ■' ^ / I ' ■■ I ' I! ' .'— I I / . “\ r X I ■—. SIC HOI J f J 1^* ^ ''ï~~ I •■ '‘'T^éixV i N '"'X 'X j ■'Voik^rxiX x'"' ,>-' Fo, 5m!: t- iXi A- xW Fig. 16. Spring pattern of movements for easily recognizable 8-year-old bighorn ram. W\i ; ^1 , ... .^.. V \ •',■>' " '.\ Mtr, ■ / ^ ^ . - .;:-.V:'--:;'.iV- . '"■•)/ V' ■■ '-'X- ' •:' ^ x jx 'I^-r::: > Ç X / Ï / T : " n r.f-f ! X'^'k Ul x = v W # #' # '"X rX # I ^ # \ : •■1^ •rr^ ! . v k ' k - k' ^ - /' X Mini:cour:dtop'"• > I :u iup t ' I ) W _!y I :\. V 11VI .I -Livor N r" - ■ ' . n . ’i V ' ^ ' .', , I K 'i V N ' !&1 \ , .- ,■ ' \1 ■ 30/ ,6234 „ \ |i k ' '‘''”Y'"'X,;'yeepy I r ./I II—< „k V '.kkf'ppef y 1 1 ^uVe7o\> y111 I V- k'l." 1 & a a # m ^ Y I -■[ Y;, S Ü 1 ' ^ Y k C lY ~ Y ~ Y l ' ' i Y - 17 Ï - l Y Fig. 17. Pattern of movements for individually recognizable bighorn ewe from the Thompson River herd Unit. I*' Mat^nKpl'Pk 4 / I ) ' ~ \ ^ ^ / vU' \ 3 4 < J . \ ■ S'" I ■ '\\ ' ^ /fA ""' I,' k.\'. I ! vMi ■#/- " ■' ‘-^ \> X 'J ' l*-^7^ r-.T \ \ : m # m '■' \ -V vr |\ X' i>^ t v i!#%./ S z V - ■> ,'/ - \ % . .A Sn,. k W W x ^ // / / .26 zf i I . / ‘V\. 59 TABLE 8. Relocation data for radio collared ewe, 21 June-16 September M iles from M iles from R elocation D ate Twnshp Range Sec. site of original site of last num ber capture relocation 6/25 1 21N 2 7W 34 .6 . 6 7/8 2 21N 2 8W 14 6. 8 2.8 7/11 3 21N 2 8W 14 6. 3 . 5 7/16 4 21N 2 7W 20 3. 6 2.8 8/2 5 21N 2 8W 13 6.2 2. 5 8/17 6 21N 2 7W 27 1.3 5. 0 8/27 7 21N 2 8W 14 7. 4 6. 0 9/4 8 21N 2 8W 24 5. 3 2.2 9/5 9 21N 2 8W 24 5. 3 .2 9/7 10 21N 2 8W 24 5.4 . 3 9/12 11 21N 2 8W 14 7. 0 1.5 9/16 12 21N 2 8W 24 5. 1 1.8 60 During periods of maximum snow accumulation (Dec. -Jan. ), sheep restricted their activities to the ruggedest crags where snow dis appeared rapidly due to wind and exposure. Snow collected on gradual, timbered slopes above those crags. Bighorns rarely descended to the lowest elevations adjacent to Highway 200. For the Clark's Fork Unit, there were no areas where large numbers of sheep congregated during winter. I found bighorns, in relatively sm all groups, wintering on suitable habitat along the south exposures which faced the Clark's Fork River. Suitable wintering areas were limited on the Thompson River Unit. Sheep were restricted to south exposures from a few miles up the Thompson River to a point approximately 2 miles northwest of its mouth. Most sheep spent the winter on slopes overlooking the Clark's Fork River. Few animals wintered along the Thompson River Canyon. From 31 January through 4 February, I observed three bighorn sheep on Liver Ridge, just north of Snider. I never saw sheep north of that point during winter. Winter centers of activity. Standard diameters were calculated for 18 marked bighorns observed during winter (Table 9). Map locations for each sighting of collared bighorns are listed in Appendix B. Distances between consecutive relocations of marked bighorn 61 TABLE 9. Activity ranges of marked bighorn sheep during winter and summer, as determined by standard diameters Mean Range of individual Sex standard diameter amp e ■T size standard diameters in m ile s W inter M ales 3. 48 5 1.13-8.2 F em a les 2.20 13 . 67-5. 59 Sum m er M ales 5. 03 6 1.40-9.25 F em a les 6.28 14 2.15-8.27 62 sheep, during winter, ranged between 0. 10 and 5.25 miles for ewes and 0. 85 and 8.25 miles for males. Average distances were 1. 30 and 3. 05 m iles, respectively. Although there were no collared sheep in the Thompson River Unit, observations on a large wintering band of ewes and lambs suggested that their movements were less extensive than those from the Clark's Fork Unit. Spring range. By late February 1974, most ewes and lambs descended from their winter ranges onto spring concentration areas at low elevation, adjacent to Highway 200, From that time, sheep began traveling extensively. Ewes 414 and 449 departed from their wintering grounds on the west face of Koo-Koo-Sint Ridge on 20 February and were resighted on 5 April approximately 0. 50 mile east of traps it e A (Fig. 4). They traveled 11 linear miles from winter to spring range. Male lamb 446, which I saw near traps it e A on 17 April, was observed 10 May on the west face of Koo-Koo-Sint, where ewes 414 and 449 spent the preceding winter. Bighorn sheep from the Clark's Fork Unit utilized the extreme southeast portion of their range extensively during spring. From late February through April, 90 percent of all marked sheep were seen on portions of Sections 33, 34, 35, or 36 (Fig. 12). By the first of May, nearly all ewes abandoned spring range and moved up to lambing grounds. Mature rams which appeared on spring concentration 63 areas in March, remained there, with yearlings of both sexes, through mid-May. From early March through late April, a band of 40 ewes and lambs occupied the southern half of Section 12 and the northern third of Section 13, just west of Thompson River Road. That group moved less than 2 miles during those months. By late April, the group disbanded. At that time, I observed single ewes and small groups of ewes traveling up the Thompson River drainage, presumably moving to lambing grounds. Lambing. The first lamb of 1974 was observed on 9 May. Four additional lambs were sighted on 24 May. Known lambing grounds are shown in Fig. 12. Observations by U.S. Forest Service personnel indicated that lambing may occur along the canyon wall between Priscilla Gulch and the West Fork of the Thompson River, Summer range. Summer range, for sheep of the Clark's Fork Unit, appeared as an expansion of winter range. The receding snow level permitted bighorns to extend their range to the highest elevations along the Koo-Koo-Sint Ridge line. Those sheep continued to use lower elevations during summer, but gradually confined their activities to higher altitudes as the season progressed. Frequent observations of collared bighorns along the Clark's Fork range suggested they did not leave the area during summer. 64 The Thompson River herd segment displayed a more classical pattern of seasonal movement. Those animals traveled up the Thompson River, using the rocky canyon wall as a migration route. Summer range included portions of the Sundance Ridge. I saw several ram groups occupying the southwest exposures of that Ridge, while ewe groups were observed along the southeast exposures overlooking the main Thompson River. Nursery bands were sighted as far north as Deerhorn Mountain. Summer activity centers. Activity centers and standard diameters were calculated for summer ranges using the same methods as for winter ranges (Table 9). Winter and summer standard diameters and distances between winter and summer centers of activity, for each marked sheep, are shown in Table 10. Pooled standard diameters for summer and winter were 5. 96 and 2. 30 m iles, respectively. The average distance traveled between winter and summer centers of activity was 2. 93 miles. Individual sheep traveled extensively during summer. Bighorns from the Clark's Fork and Thompson River Units moved back and forth over the entire lengths of their respective ranges. Average distances between consecutive relocations of marked animals during summer were 2, 35 miles for rams and 3, 71 miles for ewes. Distances ranged from 0. 50 to 8.2 5 for males and 0. 25 to 8. 30 miles 65 TABLE 10. Comparison of winter and summer standard diameters for marked bighorn sheep Standard diameter Distance in miles between A nim al no. summer and winter Winter Summer centers of activity 411 1. 00 6.00 1.25 Radioed ewe 2.00 8.10 3. 60 410 6.17 412 1. 14 4.49 4. 50 413 6.26 414 1. 64 6. 80 6. 60 415 1. 75 1.40 .50 416 1. 19 5.86 .80 420 1. 50 8.27 4.20 427 1. 13 1.65 1. 75 428 1. 00 4.80 .60 446 8.20 9.25 1.25 435 2. 60 3.02 1.00 445 4. 74 6.88 5.25 447 1. 19 8.10 4.00 436 3. 70 8.62 .40 449 . 67 6.28 8.25 174 3. 19 8.05 2. 80 213 5. 59 5. 95 2. 70 231 2. 83 2.15 . 50 66 for females. In 7 days (14-21 July) ewe 412 traveled from traps it e A to traps it e B where she was originally captured on 24 June, The distance traveled was 7.25 m iles for an average movement of 1. 04 m iles per day. The instrumented ewe characterized summer movement patterns of most sheep (Fig. 13). Her summer center of activity was located on the NW \ NE ^ Section 24, above Eddy and just west of Munson Creek. During summer, she remained in that area for 5-10 day periods, then moved away on minor excursions lasting approxi mately 1 week. She always returned to her summer center of activity. Fall range. Distribution of bighorn sheep during autumn was essentially the same as that during late winter and early spring. Ewe groups began to appear regularly on those areas in late September. In mid-October some ram groups were still occupying summer range. Rams were noted on Sundance Ridge, the northern portions of Section 10 near the Koo-Koo-Sint Ridge line, and in the old burn area on the south half of Section 28, approximately 3 m iles southeast of Munson Creek. As early as late September, yearling rams began harassing ewes by chasing them and attempting to mount. In late October, mature rams began associating with ewes and remained with them through early January. 67 Habitat use. Ninety-four percent of all bighorn sheep observed were either in the ponder os a pine-Douglas-fir/scree or subalpine scree habitat groups. Table 11 shows the bighorn*s seasonal occupation of the various habitat groups. Bighorns used southerly exposures throughout the year. Northerly exposures were densely timbered, and the possibility of seeing sheep there was minimal. Consequently, observations are biased toward southerly exposures. These animals never ventured far from rugged, rocky terrain, and distances to escape cover rarely exceeded 100 yards. Well worn trails along craggy ridgelines were used extensively by traveling bighorn sheep. The degree of use on various land-form types is shown in Table 11. Diseases and Parasites Results from fecal analyses for presence of lungworm larvae (Protostrongylus stilesi and P. rushi) are summarized in Tables 12 and 13. Of the 200 fecal samples collected during the study, 83 per cent were positive for lungworm larvae. Mean larval output for all samples was 22. 5 per gram dry feces. Seventy-seven percent of the samples had less than 10 larvae per gram dry feces, while only 8 percent had greater than 100 larvae per gram. Two samples from the Clark's Fork segment had larval counts of 804 and 1, 037 per gram dry TABLE 11. Percentage of bighorns observed on each of three habitat groups and three landform types, for each season Habitat group Landform types Season P. pine (I)^ D. -fir (11)^ Scree (X)^ Talus Broken ridge Rock outcrop Summer 0 0 100 33 48 19 F all 2 7 91 22 44 34 Winter 5 0 95 43 50 7 Spring 9 0 91 43 40 17 ^Refers to vegetation description. O) 00 69 TABLE 12. Comparison of protostrongylld larval output for various age and sex classes as determined from 100 fecal samples collected between April 1973 and January 1974 Age-sex category Adult Adult Yearlings Lambs ew es ram s Mean larval output^ 37. 39 5.34 2.75 1.03 Sam ple size 53 30 4 13 Number neg. 10 6 0 5 Number pos. 43 24 4 8 Percent pos. 81 80 100 61 Per gram dry fecal material. 70 TABLE 13. Frequency distribution of protostrongylid larval output for bighorn sheep from both herd segments, as determined from 50 fecal samples each, collected during 1-12 A pril 1974 Larval output per gram dry feces Herd segment 0 .01-1.00 1.01-10.00 10.01-100.00 >100 Thompson River 10 26 10 3 1 Clark's Fork River 2 8 19 13 8 71 feces, extremely high In comparison with other samples from that area. Larval counts for samples from the Thompson River and Clark's Fork Units averaged 4. 8 and 84. 3 per gram of dry fecal material, respectively. Lung analyses. Results from lung analyses of four hunter- shot rams, and two female bighorns, struck by vehicles, are shown in Table 14. One young ram and the female lamb were negative for both adult and larval stages of either species of lungworm. No massive congestion or consolidation of lung tissue was noted for any of the examined lungs. However, lesions were found on those lungs which were positive. Ectoparasites. Captured bighorns were thoroughly examined for ectoparasites. Particular attention was devoted to neck, ear, and genital areas as external parasites frequently localize in those areas. Of the 20 animals captured during summer, none harbored visible external parasites. Earlier, during spring, ticks (Dermacentor andersoni) were numerous on the study area. Frequently, I observed magpies (Pica pica) walking over the backs of sheep and pecking into their hair, presumably extracting ticks. Bighorns were not disturbed by the bird's activities, but would not tolerate pecking around the head. Both animals struck by vehicles during April 1974 were killed in the height of the tick season. Ticks were not visible on the adult ewe. 72 TABLE 14, Numbers of lungworm s and larvae found in six respiratory tracts from bighorn sheep shot by hunters or killed by vehicles No, larvae/gm dry feces, Sex Age K illed Lungworm collected from colon cf 3. 5 9/18/73 0 0, 1 cf 4. 5 11/ 3/73 5 9. 7 of 4.5 11/18/73 72. 8 cf 6. 5 11/19/73 8. 1 ? 7.0 4/16/74 + __b ? 11 mo. 4/24/74 0 __b ^Positive for adult lungworms, numbers not determined. ^Fecal samples not analyzed for those individuals. 73 Several ticks were seen crawling through the lamb's pelage; none . were attached. P red ation Direct predation on bighorns was not observed during this study. However, on two occasions, I observed predator-prey inter actions. On 4 October, a golden eagle (Aquila chrysaetos) harassed four adult rams by diving towards them four times in succession. Each dive forced the rams to scramble across a sheer rock face. After the fourth dive, the eagle perched atop a nearby snag, and it and the rams stared at each other for several minutes. Eventually the eagle departed. Although the large bird never actually struck the sheep, a fall from the rocky face might have resulted in the death of one of the bighorns. On 15 October, two ewes and two lambs caught my attention as they bolted down a broken rocky face. They ran approximately 75 yards, stopped, turned about, and stared up the slope at two coyotes which peered back. The coyotes departed and one ewe and both lambs commenced feeding. The other ewe spent the next 2 5 minutes slowly walking up the hill while gazing at the coyote's previous position. When she rejoined the other sheep, she occasionally stopped feeding to glance up the hill. The coyotes were not observed again. Mountain lions (Felis concolor), bobcats (Lynx rufus), and 74 black bears (Ursus amerlcanus) inhabited the sheep range, but the extent of their predation, if any, on bighorns was not determined. Once, during fall, a black bear foraged on serviceberries in the midst of a band of sheep. The sheep showed little alarm as the bear passed through the group and eventually disappeared. Grizzly bears (Ursus a ret os) reportedly persisted in the Sundance Ridge area during the study, although 1 never saw one. A ccidents The significance of accidents on bighorn mortality would be difficult to determine. However, judging from the nature of their habitat and general sheep behavior, accidents were probably more common than observed. During fall 1973, a bighorn ram with an apparently broken front leg was observed near the mouth of the Thom pson River. That animal was not seen again. On several occasions during winter, bighorn sheep were observed having difficulties crossing steep rocky faces. Sheep often made several attempts, with much slipping and sliding, at crossing steep icy surfaces. Frequently those attempts were unsuccessful, and the animals were forced to reroute their travel. Falls from some of those areas could have resulted in death or debilitating injury pre disposing an animal to predation. During April 1974, two bighorn sheep were killed by vehicles 75 on the Thompson River Road, An additional carcass was discovered along Highway 200 in an area frequented by sheep during late winter and early spring. Food Habits Rumen contents from six bighorn sheep are listed in Table 15. For the four rams harvested by hunters between 18 September and 19 November, rumen contents averaged 89, 9, and 2 percent grasses and grasslike plants, shrubs, and forbs, respectively. Grasses and grasslike plants, shrubs, and forbs constituted an average of 75, 9, and 16 percent of rumen contents for the two bighorns killed by vehicles during April. Examinations of nine feeding sites during June and July1973 indicated browse as the major forage (Table 16). During that period, the bighorns' diet consisted of 92.4, 4.6, and 3.0 percent browse, grasses, and forbs, respectively. Numerous hours of watching sheep at close range also suggested that browse was used extensively and grass sparingly during June and July. During September, bighorn sheep showed a preference for grasses. Although some shrubs were still utilized, bluebunch wheat- grass appeared to be the preferred forage. Major plant species upon which I observed bighorns feeding from October 1973 through April 1974 are listed by month in Table 17. Fall moisture caused a greenup TABLE 15. Rumen analyses of four rams killed during fall 1973 and two ewes killed during April 1974 Expressed in percent volume. Animal number and date of death Food item Ram No. 1 Ram No. 2 Ram No. 3 Ram No. 4 Ewe No. 5 Lamb No. 6 9/18/73 11/3/73 11/18/73 11/19/73 4/16/74 4/24/74 Grasses & grasslike plants Gramineae 88. 5 90. 5 86.0 89.5 85.0 66.0 Juncus sp. 3 .3 Shrubs Acer glabrum 1.0 Amelanchier alnifolia <1.0 1.2 <1.0 <1.0 4.3 Berberis repens <1.0 Purshia tridentata 1.2 Pachistima myrsinites <1.0 Unidentified shrubs 7 .0 6. 9 4 .4 5.9 7. 5 4 .6 Forbs Heuchera cylindrica 3.3 2 .0 <1.0 8.0 Centaurea maculosa 2 .9 2.2 Lupinus s eric eus 1.5 Camas sia quamash 1.5 Lomatium sp. <1.0 Unidentified forbs <1.0 <1.0 1.3 2.4 10.4 M osses Bryophytes <1.0 1.5 Conifers Pseudotsuga menziesii 7.0 -a o> 77 TABLE 16, Summer food habits of bighorn sheep as determined from examination of nine feeding sites during June and July P ercen t Taxa Mean percent canopy coverage utilization^ Shrubs Acer glabrum <1.0 0. 7 Amelanchier alnifolia 6. 9 10.6 Chrysothamnus douglasii <1.0 0. 0 Holodiscus discolor <1.0 tr. ^ Juniperus scopulorum <1.0 0. 0 Mahonia repens <1.0 0. 0 Philadelphus lewisii 10.2 41. 3 Physocarpus malvaceus <1.0 0. 0 Prunus virginiana 8. 1 6 .2 Purshia tridentata 11. 9 30.4 Ribes cereum <1.0 tr. Ribes setosum <1.0 0.0 Rosa woodsii <1.0 3.2 Sambucus coerulea <1.0 0. 0 Symphoricarpos albus 10. 0 0. 0 F orb s Achillea millefolium <1.0 0. 0 Balsamorhiza sagittate <1.0 tr. Centaurea maculosa <1.0 tr. Cerastium arvense <1.0 0.0 Collinsia parviflora <1.0 0. 0 Heuchera cylindrica <1.0 3. 0 Lomatium macrocarpus <1.0 0. 0 Penstemon albertinus <1.0 0. 0 Phacelia sp. <1.0 0. 0 Verbascum blattaria <1.0 0. 0 M o sses <1.0 0. 0 G r a sse s Agropyron spicatum 5. 7 4 .6 Bromus tectorum 3.2 0. 0 Festuca idahoensis <1.0 0. 0 Poa sp. <1.0 0. 0 ^Determined by number of instances of use, ^tr. = trace. 78 TABLE 17, Major plant species consumed by bighorn sheep, by month, from October 1973 to A pril 1974, as determined from direct observation Food item Oct. Nov. Dec. Jan. Feb. M ar. Apr Shrubs Acer glabrum X X Amelanchier alnifolia X XX Philadelphus lewisii X XX X Prunus virginiana X Purshia tridentata XX X Ribes cereum X X Rosa woodsii X Symphoricarpos albus X T r e e s Pinus ponderosa X F orb s Balsamorhiza sagittata X Centaurea maculosa X Collinsia parviflora X Fritillaria pudica X Lithophragma parviflora X Phlox hoodii XX Ranunculus glaberrimus X X G r a sses Agropyron spicatum X XXXXX X P oa sp. X XX M o sses X X XXX L ichens X X 79 of certain bluegrasses (Poa spp. ) which the sheep used readily. Browse became increasingly important as winter progressed. Mosses and lichens were regular food items in winter diets. Early spring forbs and new grasses provided sheep their major forage from late February through April, until sprouting shrubs became available. Horn Growth Horns of 18 rams harvested from the population between 1968 and 1973 were measured to determine the relationship between age of animals and rates of horn growth. I also measured horns on three ram skulls picked up by local residents (Table 18). In addition, mounted heads of three rams shot from the original population, during the early 1900's, were examined (Table 18), Growth rates of horns from the original bighorn sheep and the present population are compared in Table 19. Data on horn growth for all examined rams are listed in Appendix C. Sexual dimorphism, with respect to horn growth and configu ration, became evident early in the lives of those sheep. At 6 months of age, horns of male lambs averaged 6. 3 inches compared to 3. 5 inches for females. Horns on female lambs appeared spike-like and parallel while those of male lambs were heavier, more divergent, and wider throughout their lengths. By 18 months of age, bighorn rams showed far greater horn development than adult ewes. Horns of 80 TABLE 18, Age and horn size for bighorn sheep taken by resident hunters between 1968 and 1973, and rams shot from original herd Right Horn Left Horn O utside B asal O utside B asal A ge length circumference length circumference (years) (inches) (inches) (inches) (inches) 2 .5 25. 0 13. 8 25.2 13. 8 3. 5 34. 9 15. 8 34. 6 16. 0 3. 5 32. 5 15.2 32. 0 15.2 3. 5^ 30. Ob 14. 7 31. 0 15.2 3. 5 29.8 15. 0 30. 0 15.2 3. 5 32. 3 14. 8 31.8 14. 8 4. 5 33. 8b 15. 9 33. 7b 15. 8 4. 5^ 34. 3b 15. 5 33. gb 15. 8 4. 5 33. 0 17. 0 33.7 17. 0 4. 5 32.4 15. 3 32. 5 15. 3 5. 5 31. 8 14.4 32.0 14.2 5. 5 38. 0 16.3 37.0 16. 3 5. 5 37. 5b 15.4 36. gb 15. 7 5. 5 35. 7b 16.4 35. 7b 16.4 5, 5 34. 5b 15.4 34. 3b 15.4 5. 5 36. 5b 15. 3 37. 3b 15. 0 6. 5 36. gb 15.2 36. 7b 15. 0 6. 5 36. 4b 14. 5 35. gb 14. 5 7. 5 35. Qb 14. 8 36. 3b 15.0 7. 5^ 40. gb 14. 7 37. 5b 14. 5 8. 5 45. 3 16.0 43.0b 15. 8 3. 5*= 20.4 11.4 20.2 11. 3 6, 5° 2 9. g 13. 9 30. 0 14. 0 6. 5*" 32. 5 14.3 32.0 14.2 Skulls found on sheep range. ‘indicates broken or broomed horn tips. Rams shot from original herd. 81 TABLE 19, Average annual increment of horn growth as determined from 21 rams from the present population, and three rams from the original herd Average segment lengths (inches) Annual growth Present population Original population 1st year 6.3 4. 0 2nd y ea r 10. 9 9 .6 3rd year 7. 7 5. 9 4th year 6 .2 4. 7 5th year 4 .8 3. 1 6th year 3. 3 2 .7 7th y ea r 3. 0 2 .2 8th year 1. 8 __a ^No data available. 82 yearling rams averaged 17. 1 inches by November. At 3, 5 years of age, many rams became legal trophies under the 3/4-curl regulation (Fig. 5, C and D). New horn growth, evident as light charcoal- colored bases, commenced sometime in March. Horn growth terminated about the time of the rut. CHAPTER V DISCUSSION AND RECOMMENDATIONS Trapping Under proper conditions, portable Clover traps are well suited to a one-man trapping operation. In Colorado, Moser (1962) used Clover traps for bighorns, but concluded that success depended on severe winter weather. Portable traps proved unsatisfactory for Morgan (1970) in Idaho as mule deer monopolized the traps. Deer were only seen on four occasions at traps it e A and appeared content to lick dirt from small depressions above the trap, paying no attention to salt within the trap. Most trapping of mountain sheep is conducted during winter or spring with large corral traps, wing traps, or drop nets; using one of these devices, numerous animals can be trapped in a short time with minimum cost per sheep (Aldous et al. 1958). Major disadvan tages of Clover traps are: generally only one animal is captured per trap setting; frequent trap inspections are necessary to prevent animals remaining in traps for lengthy periods of time; several weeks are needed to capture substantial numbers of animals; and expenditure on a per animal basis is comparatively high. During summer 1973, I 83 84 spent 44 days trapping 20 bighorn sheep, for an average of pne bighorn per 2,2 days. Erickson (1970), working with Dali sheep in Alaska, captured 68 sheep In 8 days using a drop net at a natural mineral lick. I feel confident that comparable results could be obtained at traps it es A and B during early July, using his trapping system. With properly timed trapping operations, age and sex categories could be selected. By late April, pregnant ewes move away from spring concentration areas and confine their activities to lambing grounds throughout May. During early May, mature rams remain near salt licks and could probably be captured at trapslte A. Most bighorns visiting licks during May are yearlings. By mid-June, nursery bands return to salt licks and yearlings rejoin those groups. From that time through July, captures would Include ewes, lambs, and yearlings. Salt lick utilization. Mineral requirements and lick utilization by mountain sheep are treated In some detail by Honess and Frost (1942), Cowan and Brink (1949), Smith (1954), and Moser (1962). Rutherford and Schmidt (1973) discussed the value of mineralized salt blocks as dietary supplements and attracting agents for bighorns. He found that pure blocks of NaCl had greater attracting qualities and were preferred by bighorns over mineralized blocks. Similar findings by Smith (1954) suggested that bighorns preferred NaCl or at least 85 th e Na*^ ion. Growing, molting, and lactating during spring and early summer deplete animals' mineral reserves and probably account for increased visits to mineral licks. During early summer, ewes visited licks more frequently and spent more time at the salt than did other age and sex classes. Age-sex characteristics and productivity can be accurately assessed at mineral licks; however, early June ewe-lamb ratios are biased towards ewes, because ewes rarely bring their lambs to licks at that time. Similar findings were reported by Couey (1950). Geist (1971) suggests that ewe-lamb ratios are most representative from July on. The phenomenon of "baby-sitting" in bighorn sheep is referred to by several investigators (Couey 1950 and Geist 1971). On a few occasions during June, I encountered bands of several lambs attended by one ewe. At other times, several ewes, without lambs, but with swollen udders, were observed at licks. By mid-July, lambs characteristically accompanied their dams to licks. At that time, I considered ewe-lamb ratios representative of accurate counts. Collars. Observations of five collared bighorns on 13 July 1974 showed the durability of the collars. After 1 year, all flagging was secure and intact. Pendants were readable but beginning to fade slightly at their lower edges. Black pendants faded less than red ones. 86 I suggest increasing collar circumferences for sheep in this herd to 24 inches for ewes and 28 for rams. Most collars appeared sufficiently loose during summer. A few were snug during winter due to thick winter pelage. Increased collar size would result in less loss of neck hair during winter. Condition. Weights of 22 bighorn sheep from the Thompson Falls herd indicate large body size compared to those of other localities and races (Russo 1956, Aldous et al, 1958, Blood et al. 1970). Adult ewes from Thompson Falls averaged 145 pounds during early summer. Presumably they had lost 10-15 pounds at parturition, and the physiological stress of lactation precluded substantial post partum gains. It appears that the average weight for mature Thompson Falls ewes compared favorably with that obtained by Blood et al (1970) in Waterton Park, Alberta (159 pounds for 65 ewes weighed during April and May). Ewes from Thompson Falls were heavier than those from the nearby National Bison Range, which averaged 123 pounds (Berwick 1968). The four rams shot during autumn 1973, ranged in age between 3. 5 and 6. 5 years, and averaged 248 pounds live weight. The youngest ram was shot in mid-September, prior to the rut, and weighed 230 pounds, probably his maximum for the year. The other three rams were killed during November after pre-rut activities, just 87 prior to the rut. Presumably, their weights were not at their annual maximums although their fat reserves appeared good. Mean weights for seven rams shot during summer-fall and four shot during winter-spring on the National Bison Range were 258 and 218 pounds, respectively (Berwick 1968). Winter weight loss averaged 40 pounds or 15. 5 percent. A similar weight-loss pattern for the four Thompson Falls rams would suggest an average spring weight of 210 pounds which is comparable to average spring weights . (207 pounds) for rams from Waterton Park, Alberta (Blood et al. 1970). Declining body weights during winter would vary between populations, depending on range conditions, population densities and severity of winter weather. Short mild winters and available forage probably cause minimum winter weight losses for Thompson Falls bighorns. St elf ox (1974) showed that poor range conditions were partially responsible for winter weight losses by bighorn ewes in Canadian National Parks. Ewes on poor and good range averaged 20 and 13 percent declines in weight, respectively. At 14 months of age, male bighorns averaged 14 pounds heavier than females (Table 2). Blood et al. (1970) noted only a 6- pound difference in mean body weights for yearlings of both sexes from Waterton Park. During early summer, yearling males were much taller than yearling ewes, and nearly as tall as adult ewes. However, those males appeared slender compared to adult females. 88 Yearlings grew rapidly during summer and fall. At 18 months of age, yearling rams appeared as large or slightly larger than adult ewes (F ig. 5 B ). Physiological development occurred early in the lives of the Thompson Falls bighorn sheep. All yearling males, captured during early summer, showed partial descent of testes. By October their testes were descended and scrotums clearly visible. It was not known if those yearlings were capable of successfully breeding ewes; however, they were interested in ewes during fall. Buechner (1960:78) verified an 18-month-old desert bighorn ram successfully breeding two ewes during October and December 1950. One of those ewes was a yearling. Breeding age for bighorn ewes is presumably 2. 5 years. Only a few cases are recorded of breeding by yearling ewes (Bond 1936, Buechner 1960:78, Woodgerd 1964). Two ewes (410 and 416) captured as yearlings at traps it e A in 1973 were observed at that trapsite on 7 and 13 July 1974, respectively. Ewe 410 did not have a lamb, but ewe 416 was accompanied by one. That ewe had a swollen udder, but she appeared lean and in comparatively poor condition, I do not believe yearling ewes commonly breed, but with excellent nutrition some are capable of conception. Bighorn lambs grew rapidly during their first summer. Weights of four lambs captured between 4 and 14 July 1973 ranged from 30 to 55 pounds and averaged 43. Estimated ages of those lambs 89 were 7-8 weeks. Comparable aged lambs from Canadian bighorn herds averaged 35 pounds (Blood et al. 1970). Forrester and Hoffmann (1963) raised a male bighorn lamb which weighed 65 pounds at 18 weeks of age and 80 pounds at 40 weeks. Morgan's (1970) captive bighorn lamb weighed 30 pounds when 10 weeks old, and Hansen's (1965) desert bighorn lambs averaged 21 pounds at 8 weeks. Bighorn lambs on my study area were heavier than bighorns reported from other areas. Abundant milk production by lactating ewes was probably responsible for rapid weight gains by lambs. D em ography Population segments. Herd segmentation within populations was reported by Blood (1963) for California bighorns, and Geist (1971) and Erickson (1972) for Rocky Mountain bighorns; herd units occupied discrete home ranges which were in close proximity. Interchange between segments did not occur or was minimal despite absence of major physical barriers. The two herd segments of the Thompson Falls population reflects a similar situation. Geist (1971:80-84) quantified the high degree of home range fidelity demonstrated by mountain sheep. He also suggested that distinct home-range groups are typical of female sheep, whereas that concept is less applicable to rams. Rams were more mobile and mingled with different ewe home- range groups, particularly during the rut. 90 Herd segmentation for Thompson Falls bighorns is explainable on the basis on home-range behavior. I conjecture that present herd units near Thompson Falls are results of original transplant sites and subsequent dispersal patterns (Fig. 9). Herd segmentation does not preclude management of trophy rams on a population basis, since individual rams visit both herd units during the rut. However, if in the future, management should include harvesting female bighorns, consideration should be given to the discrete herd segments. Age-sex composition. The pyramidal nature of the age class structure, from young to old, is characteristic of expanding popula tions of bighorns (Table 4). Rams between the ages of 1 and 3 years constituted 67.4 percent of the 173 males classified during the rut and spring concentrations. Geist (1971) found a relatively short life expectancy was typical of expanding, "quality" populations of mountain sheep. Although hunting affects the age structure of rams, his neotenization hypothesis may explain the absence of old rams, and early maturation that I found at Thompson Falls, If so, this is a "quality" herd, I consider my calculated ewe:lamb ratios more accurate than observed ratios because yearling ewes, as nonbreeders, were com pensated for. Two-year-old ewes (>24 months) were indistinguishable from older ewes; however, the majority of those younger females 91 probably did not produce lambs, but were Included in the ewe:lamb ratios, biasing those ratios towards ewes. The 1973 lamb production for the Thompson Falls bighorn population was extremely high, approaching a 1:1 ratio of ewes to lambs. That productivity was as great or greater than most others reported (Buechner 1960:80). Survivorship of lambs over their first winter was also high (Table 3, Fig. 10). The apparently low carry over of yearlings into the 2-year age class is partially explainable. Yearling rams, approaching their second birthday, associated mostly with older rams (Fig. 11) which were not observed as readily as the ewes. In addition, yearling females could not be distinguished from older ewes. These two factors depressed the 2-year-old component while raising the adult ewe component, thus creating a bias against the 2-year age class. A ram:ewe ratio of 71:100, taken during October, was thought to be the most accurate assessment of the sex ratio. At that time, rams were banded together in pre-rut groups, and ewes, lambs, and yearlings were also grouped. The two groups appeared equally observable. Ram:ewe ratios during the breeding months were less meaningful. Rams were disbanded and often traveled alone. They were more difficult to locate than ewe groups. One or two active young rams were often observed with ewe groups; inspection of the area sometimes revealed the presence of an older ram detached 92 from the main group. Such observations suggested a bias which was not present during pre-rut. Group size and composition. Relationships between group size and population density for mountain sheep remain to be estab lished, Berwick (1968) suggested a lower limit to population density, below which group size was affected. He found a mean group size of 3. 4 for the rapidly declining Rock Creek herd in Montana. Morgan (1970) reported a decreased group size for two declining populations in Idaho between 1966 and 1970. Mean group size declined from 7. 4 to 6. 4 and 8. 9 to 5.8 for the Middle Fork of the Salmon River and the Morgan Creek herds, respectively. Smith (1954) found a mean group size of 7.3 sheep in Idaho. Blood (1963) reported an average group size of 9, 3 for California bighorns in southern British Columbia, and a population density of 50-60 sheep per square mile on the winter range. Mean group size for Thompson Falls bighorns was 5. 3 and population density on the winter range approximated 20 sheep per square mile. Blood (1963), however, found sheep concentrated in large groups on the winter range. My data indicated that Thompson Falls sheep did not concentrate during winter 1973-74. Groups were relatively small and dispersed over the winter range, which may reflect a mild winter or the nature of the range. Small group size does not necessarily infer a declining population. Conversely, many 93 groups of small size, dispersed over a winter range, may reflect a population expansion, apparently the case for the population on the study area. Group fidelity. Darling (1937), working on red deer (Cervus elaphus) in Scotland, and Altmann (1952), studying social behavior of elk in Wyoming, were probably responsible for perpetuating the idea of group fidelity or constancy of group composition in large ungulates. Knight (1970), working with large numbers of marked elk in the Sun River area of Montana, found that group constancy was not valid. Coefficients of association were low, indicating a low degree of attraction between any two marked individuals. Packard (1946) believed bighorn groups, formed in spring, maintained their integrity through the summer. Blood (1963) implied a certain degree of cohesion among California bighorn groups during particular seasons and unstable group composition at other times. However, he had no sheep marked for individual identification. Woolf et al. (1970), working with unmarked sheep, Woodgerd (1964), and Spraker and Lang (pers. comm. ), observing marked bighorns, noticed that group composition was unstable, with common interchange of individuals between groups. Erickson (1972) applied methods described by Cole (1949) and Knight (1970), and used in this study, to assess the degree of association among marked bighorns in the Sun River herd of 94 Montana. His calculated mean coefficient of association for summer and winter was 0. 2 5, which agrees closely with that found in the present study (0. 27) during the entire year. Erickson's mean coefficients of associations for summer and winter were 0. 56 and 0. 40, respectively. Those values compare favorably with those found during this study (0. 45 and 0. 37 for summer and winter, respectively). The closeness of those values for the Sun River herd in comparison to the Thompson Falls population suggest similar degrees of association among individuals in native and introduced populations of bighorns. Fluctuating group composition apparently is inherent behavior in bighorns, and does not imply population instability. Distribution and Movements Southerly exposed escarpments and rocky canyon walls along major stream courses comprised the sheep range. Southerly exposures were important for bighorns during all seasons. Densely timbered northerly exposures were of little or no significance to bighorns. If only habitat groups I, II, and X were considered primary sheep habitat (a reasonable assumption--see Table 11 and Fig. 3), the sheep range would approximate 50 square miles during summer and 12 square miles in winter. Summer density of bighorn sheep would approach five per square mile. Winter density, discussed earlier, would vary with the severity of winter weather. Greatest 95 sheep density occurred during spring (March-Apr 11) when numbers of animals on concentration areas approached 40-50 per square mile. Seasonal population density has little meaning unless considered In conjunction with environmental parameters such as vegetatlonal composition, forage productivity and availability. Winter range. Shrubs predominate on the Thompson Falls winter range and are generally available to herbivores even when moderate snow covers the sparse grasses and other low-growing vegetation. Matthews (1973) concluded that the conspicuous lack of browse on Wlldhorse Island, Flathead Lake, Montana, Is limiting further expansion of the bighorn population. Typically mild winters, abundant browse, and wide dispersal of animals over winter range apparently insures low winter mortality for Thompson Falls bighorn sh eep . Winter centers of activity. Bighorn sheep remained relatively mobile on the winter range (Table 9). Mean standard diameters during winter were substantially higher (3. 88 and 2.20 for males and females, respectively) than those reported by Erickson (1972) (0, 92 and 1. 42). However, Erickson believed that severe winter conditions during his study may have abnormally restricted bighorn movements. He also found that rams moved less than ewes during winter. Morgan (1970) reported an average movement of 1. 59 miles for ewes and 2.2 5 miles 96 for rams on Idaho winter ranges. My data also suggested that males moved more than females on the winter range, with average distances between consecutive relocations being 3,05 and 1.30, respectively. Only five young rams (two lambs, three yearlings) compared to 13 ewes (2 lambs, 1 yearling, 10 adults) were collared. Thus, my comparative movement data may be biased between the sexes. Furthermore, young rams may move more extensively than mature rams exhausted from the rut. Geist (1971) implied a small winter range for Stone rams after the rut. Spring range. Arrival on spring concentration areas coincided with greenup of grasses and forbs on those areas. Ewe groups occupied spring ranges approximately 60 days before departing for lambing grounds in late April. Rams arrived later and departed later than ewes, from the spring ranges, but spent approximately the same number of days on them. During spring and early summer, large numbers of bighorns occurred on Section 35, R27W T21N. Sheep were observed in that area during all seasons. A major salt lick (trapsite A) was located on that section, approximately one quarter mile northeast of a large year-round spring. Past grazing pressure by domestic stock left the range in poor condition. The greater portion of that section is privately owned and currently for sale. Purchase of that property by the State Fish and Game 97 Department is recommended so the area can be managed specifically for bighorn sheep. Cattle grazing should be excluded, and the single access road closed to unauthorized travel. Lambing. Lambing seasons vary between races of North American sheep. The climate of an area is considered the controlling factor (Geist 1971). Demlng (1963) found the lambing season for desert sheep to occur during several months and Hansen (1965) reported seeing new lambs during all months of the year. Lambing periods are more synchronous for northern bighorns than for desert sheep. Blood (1963) found that California bighorns in southern British Columbia lambed during a 7-week period between late April and June. On Wildhorse Island, Montana, Matthews (1973) observed the first lamb of 1972 on 26 April, but believed peak lambing occurred in late May. During the present study, the earliest date on which a lamb was observed was 9 May 1974. Other data indicated peak lambing occurred between 20 and 30 May, Lambing grounds defined on the study area (Fig. 12) were not exclusive. The precipitous nature of the topography provides numerous other suitable lambing areas. I was unable to visit all those areas during May. Summer range. Limited observations during late summer indicated that sexes remained separate on summer ranges. Similar observations were reported by Woolf et al. (1970). Southwest 98 exposures of Sundance Ridge, adjacent to the West Fork of the Thompson River, were common summering areas for rams from both herd segments. Although observations were limited, I never saw ewes in that area. Summer centers of activity. Pooled standard diameters for summer were 62 percent larger than for winter, indicating that sheep of either sex had larger seasonal ranges during summer (Table 10). Average distances between consecutive relocations were 21 percent greater during summer than winter, even though time between resightings was generally less during summer. Distances traveled between resightings varied from 0. 2 5 to 8. 30 m iles. Morgan (1970) reported average summer movements of 1. 68 and 5, 0 miles for ewes and rams, respectively. Erickson (1972) found that distances between consecutive relocations of 21 marked bighorns, during summer, averaged 1. 78 miles (pooled) and ranged from 0 to 6. 88 miles. In the Thompson Falls area, ewes averaged 3,71 miles (24 observations) and rams 2.35 miles (10 observations) between consecutive relocations, and ranges were 0.25-8. 30 and 0, 50-8,25 miles, respectively. Smith (1954) reported very short seasonal migrations for bighorns in the Middle Fork of the Salmon River drainage, while sheep from the East Fork of that river traveled as much as 40 miles between winter and summer ranges. Morgan (1970) found bighorns on his study 99 area averaged 22.4 miles between winter and summer ranges, Couey (1950) recorded migrations of approximately 10 miles for Sun River bighorns while Erickson (1970) found an average migration of 6.44 miles between winter and summer ranges. Both migratory and non- migratory bighorns were reported by Sugden (1961) for the Chileotin region of British Columbia and Woolf et al. (1970) for Yellowstone Park. The average movement between summer and winter centers of activity for the Clark's Fork Unit bighorns was 2. 93 m iles, and ranged from 0.50 to 8.2 5 m iles. Movements between seasonal ranges generally Involved changes in elevation and/or a lateral shift along the Clark's Fork Unit range. Bighorns from the Thompson River Unit traveled as far north as Deerhorn Mountain, 15 airline miles from their wintering area near the mouth of the Thompson River. The investigators, mentioned above, indicated that once bighorns were on summer ranges, they moved very little. This was not the case at Thompson Falls. Movements on summer ranges were extensive and frequent. Individual sheep moved the entire lengths of their respective ranges several times during the summer. Factors motivating such movements were not known. However, the high degree of mobility in summer caused wide dispersal of sheep during that season, thus eliminating problems attendant on large concen trations of animals. 100 Fall range. Smith (1954), Blood (1963), and Erickson (1972) believed early fall snowstorms on summer ranges precipitated bighorn movements onto winter ranges. Berwick (1968) observed sheep arriving on the Rock Creek winter range in September, prior to inclement weather on their summer range. Near Thompson Falls, the return of bighorns to fall ranges occurred prior to any major snow storms on the summer ranges. Ewes arrived first, followed a few weeks later by rams. Some mature rams remained on summer ranges well into October. The appearance of sheep on autumn ranges coincided with a cooling trend in the weather and the first fall rain showers. There was a subsequent greenup of certain grasses (Poa sp. ) which sheep fed upon extensively. Diseases and Parasites In recent years, the lungworm-pneumonia-complex in North American bighorn sheep received considerable attention (Buechner 1960, Forrester 1971, Uhazy et al. 1973). Forrester (1960) and Forrester and Senger (1964) treated, in detail, the lungworm problems of Montana's bighorn sheep populations. St elf ox (1974) related the dis ease-parasite problem to range conditions and herd productivity for Canadian bighorns. Massive population die-offs attributed to the lungworm-complex were reported by various investigators (Couey 101 1950, Smith 1954, Moser 1962, Demarchl and Demarchi 1967, and St elf ox 1971). Forrester and Senger (1964) suggested lung analysis was the most accurate assessment of protostrongylid infection, since larval discharge in the feces varied daily as well as seasonally. From the six lungs examined during this study, four (67 percent) were positive for Protostrongylus stilesi or P. rushi. Uhazy et al, (1973) thought that sufficiently large numbers of fecal samples reflected the degree of infection in a herd. The 200 fecal samples collected during this study were thought to represent an adequate sample size. Larval discharge from bighorn populations in Waterton, Banff, and Jasper Parks, Canada, averaged 594, 626, and 2, 375 per gram feces (St elf ox 1974). Uhazy et al. (1973) concluded that heavy infestation was reflected in larval counts over 1, 400 per gram feces, while counts averaging 157 larvae per gram feces were considered light. None of the samples from Thompson Falls had larval counts exceeding 1,037 per gram feces. Larval discharge averaged 22. 5 per gram, dry feces, far below the 157 reported for light infestation. Other western Montana bighorn populations were comparable to the Thompson Falls herd. Mean larval outputs for bighorns from the National Bison Range, Wildhorse Island, and Kootenai Falls were < 10, 30, and 40 per gram dry feces, respectively (Forrester and Senger 1964). Herd infection was 83 percent for Thompson Falls, the same as that found in the 102 Kootenai Falls herd (Forrester and Senger 1964). Couey (1950) reported lungworm common in the original Thompson Falls bighorn sheep. However, his conclusion was based on 10 fecal samples, and he failed to mention numbers of larvae. The 83 percent incidence of lungworm and average larval discharge of 22, 5 per gram feces indicate a low degree of infestation in the present herd. Lungworm infestations are probably low because mild winters enhance bighorn mobility, prevent large concentrations on specific sites over long periods of time, and insure against range depletion in those areas. Animals forced to winter on small areas for long periods increase their chances of ingesting land snails carrying infective state Protostrongylus larvae. Heavy use of browse during winter and early summer probably reduces ingestions of intermediate hosts which are commonly found near ground level in low-growing vegetation. The disparity in Protest rongylus infection between the two herd segments may result from different movement patterns. The number of animals in the Thompson River Unit is approximately half that in the Clark's Fork Unit. Sheep from the latter unit summer on an expanded version of the winter range, and portions of the winter range are utilized throughout the year. Bighorns from the Thompson River Unit disperse widely over summer range and visit winter range only occasionally during summer. 103 Population Regulation Low levels of lungworm infection do not preclude bighorn die offs. Berwick (1968) and Matthews (1973) documented recent declines in two western Montana bighorn populations, Lungworm infections were light in both cases. Buechner (1960) suggested that certain bighorn populations living under generally mild environmental conditions displayed wide fluctuations in population numbers. Die-offs in such herds appeared during abnormally severe winters despite low endoparasite loads. A nonverminous pneumonia was implicated in some of the declines (Marsh 1938, Fillmore 1958). Under environ mentally stressful situations (overly dense population, harsh winter weather, range forage depletion) low endoparasite levels may have a compounding influence on healthy animals, thus predisposing them to viral or bacterial agents which travel rapidly through the population. The Thompson Falls herd has all the qualifications of a "high quality" population (Geist 1971); animals are large, mature rapidly, and interact vigorously; productivity and subsequent recruitment are high; predation is insignificant; overall mortality is low; lungworms are at a low level. The population is expanding at a rapid rate, unchecked by effective intrinsic or extrinsic factors. However, severe winters occur sporadically in the Thompson Falls region, and a future population crash seems probable. Preventive management, by removal of animals from sex and age classes other than trophy 104 rams, is recommended. Thompson Falls bighorns would provide excellent stock for transplanting, and summer transplanting could be easily accomplished. Harvesting female bighorns is the logical alternative to transplanting, and probably represents a more realistic approach to the problem. Harvest of surplus ewes on a sustained basis would stabilize the population at present levels which appear to be optimum with respect to productivity. Food Habits From rumen analyses and direct observations of grazing sheep during fall, grasses, browse, and forbs accounted for 89, 9, and 2 percent of the fall diets. Sun River bighorns consumed 86. 5 percent grasses during fall, but only 1. 9 percent browse; use of grass declined to 36. 0 percent during winter while browse consumption increased to 43. 0 percent (Shallenberger 1965). Bighorns in Yellow stone National Park used grasses, forbs, and browse in the ratio of 61.4, 17.2, and 21. 5 percent, respectively, during winter (Oldemyer 1966), The winter diet of sheep on Wildhorse Island consisted of nearly 91 percent grasses (Matthews 1973); however, browse was conspicuously scarce on the Island, and that which was available was overused. Matthews concluded that lack of browse was the major limiting factor to further growth of the sheep population. Although utilization was not quantified, browse was the major winter forage for 105 bighorns on the Thompson Falls sheep range. Important species utilized were mockorange, serviceberry, and bitterbrush. These species were also most abundant, A shift from grasses during fall to browse in winter corresponds with the nutritional status of these forage types. Grasses have their greatest nutritional value during fall. Crude protein content is higher for browse than grasses during winter (Knoche 1968). Bighorns on a high protein diet during winter should have good survival rates, high productivity, and produce large healthy lambs with high probability of survival. The gradual shift from browse to grasses and forbs corres ponds with spring greenup. The subsequent shift back to browse during early summer (Table 16) occurred while major grasses were maturing and new sprouts on shrubs were available. There may have been some bias on feeding sites examined during summer. All sites were on steep talus or scree slopes where shrubs predominated, and very little grass was available. However, other observations during the same period suggested that browse was indeed these bighorns' major food. The abundance and availability of browse on my study area is a definite asset to the bighorn population. The comparative rarity of grasses may limit future population growth. I recommend a follow-up study to determine the carrying capacity for ungulates, as reflected by range conditions. 106 Horn Growth Rapid horn development in bighorn rams is characteristic of expanding "high quality" populations (Geist 1971). In those popula tions, males mature rapidly, participate in the rut at an early age, interact vigorously, and consequently have a shorter life expectancy than males from "low quality" populations. The comparison of age and horn growth between rams from the National Bison Range, Wildhorse Island (Taylor 1962:65) and Banff National Park (Geist 1971: 50) substantiated this theory. Bison Range rams typically had tre mendous early horn growth, but few lived beyond 7 years of age. Rams from Banff Park had poor early development, distributed their horn growth over the later years of life, and commonly lived to 12 years of age. Thompson Falls bighorn rams had horn growth rates slightly greater than rams from either the Bison Range or Wildhorse Island, and substantially greater than rams from Banff Park (see Geist 1971:50 and Table 19, this report). Geist (1971) collected 39 ram skulls ranging in age from 7 to 17 years from Banff Park. The longest horn he found, that of a 12- year-old ram, measured 43. 5 inches (no details as to brooming). An 8-year-old ram shot from the Thompson Falls herd in 1968 had one 45. 3-inch horn. From average annual horn segment growth (Table 19) it was calculated that mean horn length (unbroomed) for an 8-year-old ram would be 44. 0 inches. Eight-year-old rams are rare in the Thompson Falls herd, and it is 107 doubtful that any attain 10 years of age. However, 7-8 year old males from "high quality" populations are comparable in all respects to much older males in "low quality" populations. The original theory behind sport hunting for bighorn sheep was to remove senile old rams (10+) from populations. This qualifi cation is not applicable to Thompson Falls rams since few, if any, attain that age. Seven- and 8-year-old rams constitute the "old age classes" and should be selected for by trophy hunters. Analysis of age composition for 18 hunter-harvested rams (Table 18), indicate this is not what occurred. Only two (11 percent) of the hunter-shot rams were 7. 5 or 8.5 years old, while five (28 percent) were 3. 5 years or less. Nine (50 percent) fall within the 4. 5-5. 5 year age c la s s e s . Old rams are not represented in the harvest because: 1) they are not as numerous as younger age classes, 2) they are more difficult to hunt, and 3) the manner in which most sheep hunters hunt this herd places most of the pressure on intermediate-aged rams which are most active during the rut. Typically, permit holders wait until late in the season (November), drive Highway 200 spotting for sheep in the crags, and select rams associating with ewe groups. As discussed earlier, older rams were often observed detached from those ewe groups and consequently overlooked by many hunters. From a trophy hunting perspective, the present situation in 108 the Thompson Falls area is unfortunate. Many of the young animals which were shot had the potential of becoming exceptionally large trophies had they lived to 7 or 8 years of age. Should the Montana Fish and Game Department elect to initiate a trophy ram hunt in the Thompson Falls area, the following would improve the quality of the hunt: 1) Raise the requirements for legal rams, skewing the harvest towards those males 7 years of age and older. This would necessitate a hunter indoctrination program similar to that used for desert sheep in Nevada (Jonez 1966). 2) Reduce the season to the month of September, This would concentrate hunting pressure on the rams' summer ranges and preclude road hunting. Under the current regulation (3/4 curl) and long season, increased permits would result in additional harvest of young age classes. Hunter success was 100 percent every year since 1968, except 1971 when it was 80 percent. Management Options Natural population regulation. This option would preclude hunting. Natural regulatory mechanisms would be operative. Herd quality would decline and periodic catastrophic reductions in population numbers would be expected. A complete die-off similar to that of the 109 original herd is a possibility. Three-fourths curl harvest. Under this plan, maximum numbers of 3/4-curl rams would be harvested. At the current population level, eight rams could be harvested annually. Since 12 rams are recruited into the legal category yearly, the remaining four rams would be allowed to advance to older age classes. Within a few years, the number of males in older age groups would be reduced. Natural regulatory mechanisms with attendant problems would still be op erative. Trophy rams. Hunting for rams 6 years of age or greater is suggested under this plan. Permit holders would be trained to distinguish trophy class rams, thus relieving hunting pressure on young rams. This would insure a greater recruitment of males into the trophy category. A short early season is recommended to encourage a quality hunt and preclude road hunting. Maintenance of the present five permits would be appropriate, but the hunter success rate might decline. Success should increase within a few years, as the previously harvest able young rams would become legal trophies under the new regulations. Maximum productivity. Maintenance of present population size is the desired objective under this system. Management would 110 include removal either through transplanting or harvesting on a permit basis of five and three ewes from the large and small herd segments, respectively, to stabilize the current population increase. Future adjustments to these numbers would depend on the population response as determined by population estimates. Removal of productive females would have an almost immediate depressing affect on the population. Maximum productivity, in numbers harvested, would result from taking as many lambs as possible without impairing numbers in higher age classes. With direct supervision, female lambs and old ewes could be removed in late summer. Any ewes could be taken in early winter when lambs are no longer dependent upon them, but local residents would object to harvesting ewes on the winter range. The maximum productivity option could be combined with either the 3/4- curl or trophy ram options. CHAPTER VI SUMMARY Ecology of bighorn sheep near Thompson Falls, northwestern Montana, was investigated between March 1973 and May 1974. Data collection involved capture, marking and release of 20 mountain sheep. One adult ewe was instrumented with a radio transmitter. Trapping and marking systems proved adequate; however, an alternate trapping method was advised for better results. Greatest mineral lick utilization occurred during late June and early July. Body weights and general condition of 22 bighorns examined indicated large, healthy sheep in comparison to bighorns from other areas. One hundred seventy-one observations of marked bighorns revealed: 1) the sheep population consisted of two herd segments, with intersegment association restricted to rams; 2) population numbers approached 240 individuals, with 68 percent occupying the Clark's Fork Unit; 3) over-winter mortality for sex and age classes repre sented by marked sheep was low, as 19 of the 20 individuals were observed during spring 1974. High survivorship was attributable to abundant available browse, mild weather, insignificant predation, and lack of competition from other ungulates; 4) a low degree of group 111 112 cohesion, with common interchange of individuals between groups; 5) locations of winter and summer centers of activity for individual animals. Winter mobility of bighorns was lower than summer, but greater in both seasons than that reported by other investigators; and 6) inter seasonal movements. Lungworm loads appeared low, with an average discharge of 22, 5 larvae per gram dry feces. The herd was 83 percent infected, with greatest infection occurring in the Clark's Fork Unit. Food habits changed seasonally, with major food items being grass, browse and grass, grass and forbs, and browse for fall, winter, spring, and early summer, respectively. The availability of browse through the winter was considered an asset to the bighorns. Rapid horn development and physical maturation reflected a "high quality" sheep population, but created a skewed harvest situation. Rams 4. 5 years of age and younger accounted for approxi mately 44 percent of the hunter-shot rams. I discussed removal of surplus animals from all sex and age classes, raising the legal requirements for rams, and shortening the hunting season to promote quality hunting as alternatives for management. LITERATURE CITED Alden, W, C. 1953. Physiography and glacial geology of western Montana and adjacent areas. U. S. Geological Survey Professional Paper 231. U.S. Government Printing Office, Washington, D. C. 200 pp. Aldous, M. C ., F. C. Craighead, Jr., and G. A. Devan. 1958. Some weights and measurements of desert bighorn sheep (Ovis canadensis nelsoni). J, Wildl, Mgmt. 22(4):444-445. Alt, D. D ., and D. W. Hyndman. 1972. Roadside geology of the northern Rockies. Mountain Press Publishing Co., Missoula, Montana. 280 pp. Altmann, M. 1952. Social behavior of elk Cervus canadensis nelsoni, in the Jackson Hole area of Wyoming. Behavior 4(2): 116-143, Anonymous. 1953. Mines and mineral deposits of Sanders County Montana. Mont. Bureau of Mines and Geology, Butte. Bull. 34. Berwick, S. H. 1968. Observations on the decline of the Rock Creek, Montana population of bighorn sheep. M. S. Thesis. University of Montana, Missoula. 245 pp. Blood, D. A. 1963. Some aspects of behavior of a bighorn herd. Canad. Field Nat. 77(2):77-94. ______, D. R. F look, and W. D. Wishart. 1970. Weights and growth of Rocky Mountain bighorn sheep in western Alberta. J. Wildl. Mgmt. 34(2);451-455. Bond, R. M. 1936, Special report on bighorn sickness in Glacier National Park. U.S. Park Service, Glacier National Park files, 9 pp. Buechner, H. K. 1960, The bighorn sheep in the United States, its past, present, and future, Wildl. Mono. No. 4. 174 pp. 113 114 Cole, L. C. 1949, The measurement of interspecific association. Ecology 30(4):411-424. Couey, F. M. 1950. Rocky Mountain bighorn sheep in Montana. Mont. Fish and Game Comm. , Helena. Bull. 2. 90 pp. ______, and A. Schallenberger. 1971. Bighorn sheep. Game Management in Montana. Mont. Fish and Game Dept., Helena. Fed. Aid Proj. W-3-C:97-105. Cowan, 1. McT. , and V. C. Brink, 1949, Natural game licks in the Rocky Mountain National Parks of Canada. J. Mammal. 30(4): 379-387. Cox, Ross. 1831. Adventures on the Columbia River. Henry Colburn and Richard Bentley, London. Vol. I, p. 231. Craighead, J. J ., M. G. Hornocker, M. W. Shoesmith, and R, I, Ellis. 1969. A marking technique for elk. J. Wildl. Mgmt. 33(4):906-909. Darling, F. F. 1937. A herd of red deer: a study in animal behavior. Oxford University Press, London, 215 pp. Demarchi, R. A., and D. A, Demarchi. 1967. Status of the Rocky Mountain bighorn. Wildl. Rev, 4(4):10-14. Deming, O. V. 1963. Bighorn breeding. Trans. Desert Bighorn Council, Las Vegas, Nev. 7:92-111. Erickson, G. L. 1972. The ecology of Rocky Mountain bighorn sheep in the Sun River area of Montana, with special reference to summer food habits and range movements. Unpubl. M.S. Thesis. Montana State University, Bozeman. 50 pp. Erickson, J. A. 1970, Use of drop net and collars in study of Dali sheep. Trans. Northern Wild Sheep Council, pp. 20-21. Ferris, W. A. 1810-1873. Life in the Rocky Mountains. A diary. Special collection. University of Montana Library, Missoula. Forrester, D. J. 1960. A preliminary investigation of the Protostrongylin lungworm-bighorn sheep relationship in Montana, M.S. Thesis. University of Montana, Missoula, 7 9 pp. 115 Forrester, D. J, 1971. Bighorn sheep lungworm-pneumonia complex. In Parasite Diseases of Wild Mammals, Edited by J. W. Davis and R. C. Anderson. Iowa State University Press, Ames, Chap. 6, pp. 158-173. ______i and R. S. Hoffmann. 1963, Growth and behavior of a captive bighorn lamb, J. Mammal. 44(1): 116-118, , and C. M. Senger, 1964. A survey of lungworm infection in bighorn sheep of Montana, J. Wildl, Mgmt. 28(3):481-491, Geist, V. 1966, Validity of horn segment counts in aging bighorn sheep. J, Wildl. Mgmt. 30(3):634-635. ______. 1971. Mountain sheep; a study in behavior and evolution. University of Chicago Press, Chicago and London. 383 pp. Guthrie, A, B ., Jr. 1945, Sheep and goats, Atlantic Monthly 175(4):113-114. Hansen, C. 1965. Growth and development of desert bighorn sheep, J. Wildl. Mgmt. 29(2):387-391. Harrison, J. L. 1958, Range of movement of some Malayan rats. J, Mammal. 39(2):180-206. Hayne, D. W. 1949. Calculation of size of home range, J. Mammal, 30(1):1-18. Honess, R. F. , and N. M. Frost, 1942, A Wyoming bighorn sheep study, Wyo. Game and Fish Dept., Cheyenne. Bull. 1, 127 pp. Jonez, A. 1966. Trophy for bighorn sheep. Proc. Ann. Conf. West. Assoc, of State Game and Fish Comm. 46:72- 75. Knight, R. R. 1970, The Sun River elk herd. Wildl. Mono, No, 23, 66 pp. Knoche, K. G. 1968. The ecology of the Rattlesnake Creek, Montana, mule deer winter range. M. S. Thesis. University of Montana, Missoula. 152 pp. Marsh, H. 1938. Pneumonia in Rocky Mountain bighorn sheep. J. Mammal, 19(2):214-219, 116 Matthews, J. W. 1973. Ecology of bighorn sheep on Wildhorse Island, Flathead Lake, Montana. M.S. Thesis, University of Montana, Missoula. 88 pp. Morgan, J. K. 1970. Ecology of the Morgan Creek and East Fork of the Salmon River bighorn sheep herds and management of bighorn sheep in Idaho. Research Completion Report, Ida. Fish and Game Dept., Boise, Proj. W-142-R-1. 155 pp. Moser, C. A. 1962. The bighorn sheep of Colorado. Colo. Game, Fish and Parks Dept. , Denver. Tech. Pub. No. 10. 49 pp. Oldemyer, J. L. 1966, Winter ecology of bighorn sheep in Yellow stone National Park. M.S. Thesis. Colorado State University, Fort Collins, 107 pp. Packard, F. 1946. An ecological study of the bighorn sheep in Rocky Mountain National Park. J. Mammal. 27(l):3-2 8. Pillmore, R. E. 1958. Problems of lungworm infection in wild sheep. Trans. Desert Bighorn Council 2:57-63. Russo, J. P. 1956. The desert bighorn sheep in Arizona. Ariz. Game and Fish Dept., Phoenix. Wildl. Bull. 1. 153 pp. Rutherford, W. H ., and R. L. Schmidt. 1973. Techniques for supplementing diet, attracting and baiting bighorn sheep. Colo. Game, Fish and Parks Dept. , Denver. Game Info. Leaflet No. 95. 3 pp. Schallenberger, A. D. 1965. Food habits, range use and inter specific relationships of bighorn sheep in the Sun River area, west central Montana. M.S. Thesis. Montana State University, Bozeman. 44 pp. Set on, E. T. 1929. Lives of game animals. Vol. III. Doubleday, Doran Co. , Garden City, N. Y. 749 pp. Smith, A. H. 1936-1938. Kalispell Ethnography. Manuscript of field records. P. 82. Smith, D. R, 1954. The bighorn sheep in Idaho, its status, life history and management. Ida. Dept, of Fish and Game, Boise. Wildl. Bull. 1. 154 pp. 117 Southwood, T. R. 1966. Ecological methods. Methuen and Co., Ltd., London, 391 pp. St elf ox, J, G. 1971. Bighorn sheep in the Canadian Rockies: a history 1800-1970. Canad. Field Nat. 85(2):101-122. ______. 1974. Range ecology of bighorn sheep in relation to self- regulation theories. Unpublished paper presented at the Northern Wild Sheep Council Meeting, Great Falls, Montana. 44 pp. Sugden, L. G. 1961. The California bighorn in British Columbia. B. C. Dept. Recreation and Conservation, Victoria. 58 pp. Taylor, R. A. 1962. Characteristics of horn growth in bighorn sheep rams. M.S. Thesis, University of Montana, Missoula. 128 pp. Uhazy, L. S. , J. C. Holmes, and J. G. St elf ox. 1973. Lungworm in the Rocky Mountain bighorn sheep of western Canada. Canad. J. Zoology 51(8):817-824. U.S. Dept, of Comm. 1970. Climatological Summary. National Oceanic and Atmospheric Admin., Asheville, N.C. Varney, J. R. 1971. A tracking and telemetry system for wildlife research. Institute of Electrical and Electronics Engineers, National Telemetry Conf., Washington, D, C ., Record: 247-252, White, M. C. 1950. David Thompson's Journals relating to Montana and adjacent regions, 1808-1812. Montana State University Press, Missoula, 345 pp. Woodgerd, W. 1964. Population dynamics of bighorn sheep on Wildhorse Island, J. Wildl. Mgmt, 28(2):381-391, Woolf, A. , T. O, O'Shea, and D. L. Gilbert. 1970. Movement and behavior of bighorn sheep on summer ranges in Yellowstone National Park. J. Wildl. Mgmt. 34(2):446-450. Yoakum, J. 1963. Reestablishing native bighorn ranges. Trans. Desert Bighorn Council 7:122-12 5. APPENDIX A LIST OF PLANT SPECIES Scientific Name Common Name TREES Cupressaceae Juniperus communis Ground juniper Juniperus scopulorum Rocky Mountain juniper Thuja plicata Western red cedar P in aceae Abies grandis Grand fir Abies lasiocarpa Subalpine fir Larix lyallii Alpine larch Larix occidentalis Western larch Picea engelmannii Engelmann spruce Pinus albicaulis Whltebark pine Pinus contort a Lodgepole pine Pinus monticola Western white pine Pinus ponderosa Ponderosa pine Pseudotsuga menziesii Douglas fir Tsuga heterophylla Western hemlock Tsuga mertensiana Mountain hemlock T axaceae Taxus brevifolia Western yew S a lica cea e Pop ulus trichocarpa Black cottonwood 118 119 Scientific Name Common Name FORBS AND WEEDS Boraginaceae Mertensia paniculata B luebell Campanulaceae Campanula rot undifolia H arebell Caryophyllaceae Cerastium arvense Chickweed Saponaria officinalis Bouncing bett C om positae Achillea millefolium Yarrow Anaphalis margaritaceae Pearly everlasting Antennaria neglecta Field pussytoes Arnica cordifolia A rnica Halsamorhiza sagittata Arrowleaf balsamroot Centaurea maculosa Spotted knapweed Chrysopsis vlllosa Golden aster Cichorium intybus C hicory Erigeron comp os it us Fernleaf fleabane Gaillardia aristata G aillardia Senecio canus Woolly groundsel Taraxacum officinale Dandelion L abiatae Mentha arvensis F ield mint Prunella vulgaris Self heal Leguminosae Astragalus convallarius Timber milk vetch Luplnus sericeus Silky lupine 120 Scientific Name Common Name Trifolium repens White clover Vicia americana American vetch L ilia c ea e Calochortus spp. Sego lily Camassia quamash C am as Clint onia uniflora Q ueens cup Clematis columbiana C lem atis Brodiaea douglasii Wild hyacinth Disporum trachycarpum F a iry b ells Erythronium grandiflorum Dogtooth violet Fritillaria pudica Yellow bell Smilacina stellata False Solomonseal Trillium ovatum Wake rob in Xerophyllum tenax B ea rg ra ss Zigadenus venenosus Death camas M alvaceae Hypericum perforatum Common St. Johnswort Sphaeralcea coccinea Scarlet fais email ow O nograceae Clarkia pulchella C larkia Epilobium angustifolium F irew eed Orchidaceae Calypso bulbosa Fairyslippers Plantagenaceae Plant ago purshii Wooly plantain 121 Scientific Name Common Name Polemoniaceae Collomia linearis Narrow leaved Collomia Gilia aggregata Scarlet gilia Phlox hoodii White phlox Polyonaceae Eriogonum bellum Sulphur eriogonum Eriogonum flavum Yellow eriogonum Rumex acetosella Sheep sorrel Primulaceae Dodecatheon conjugens Shooting star Ranimculaceae Aquilegia flavescens Yellow columbine Clematis columbiana Rock clematis Delphinium bicolor Low larkspur Ranunculus glaberrimus Sagebrush buttercup R o sa cea e Fragaria vesca Straw berry Geum triflorum Prairie-smoke Potent ilia gracilis Northwest cinquefoil Sanguisorba occidentalis Burnet R ubiaceae Galium boreale Northern bedstraw Saxifragaceae Heuchera cylindrica Round leaved alum root Lithophragma parviflora Starflow er Saxifraga intergrifolia Saxifrag 122 Scientific Name Common Name Scrophylariaceae Castilleja hispida Indian paintbrush Collinsia parviflora Blue-eyed Mary Linaria vulgaris Butter and eggs Orthocarpus lut eus Yellow owl-clover Penstemon procerus Little leaf penstemon Penstemon wilcoxii Wilcox penstemon Umbelliferae Lomatium dissectum Lom atium Lomatium macrocarpum Desert parsley Lomatium triternatum Nine leaf bis cuit root Osmorhiza occidentalis Western sweet root Perideridia gairdneri Yampa V io la cea e Viola adunca Western violet Viola glabella Yellow violet SHRUBS AND TREES A cera cea e Acer glabrum Mountain maple Apocynaceae Apocynum androsaemifolium Spreading dogbane Berberidaceae Berberis repens Oregon grape B etu laceae Betula papyrifera Paper birch 123 Scientific Name Common Name Caprifoliaceae Linnea borealis Twin flower Lonicera ciliosa Honey suckle Symphonyc arp os albus Common snowberry Celastracea Pachistima myrsinites Mountain-lover C om positae Artemisia frigida Fringed sagebrush Chrys othamnus nauseosus Rabbitbrush C ornaceae Cornus stolonifera Dogwood E rica cea e Arctostaphylos uva-ursi B earb erry Chimaphila umbellata Princess pine Menziesia ferruginea M en ziesia Vaccinium membranaceum Thinleaved huckleberry Grossulariaceae Ribes cereum Squaw currant Rib es setosum Currant Ribes hudsonlanum Hudson gooseberry Hippuridaceae Oplopanax horridum Devil's club R ham naceae Ceanothus sanguineus Redstem ceanothus Ceanothus velutinus Evergreen ceanothus 124 Scientific Name Common Name Hydrangeaceae Philadelphus lewisii M ockorange R o sa cea e Amelanchier alnifolia Serviceberry Crataegus douglas ii Hawthorn Holodiscus discolor Ocean spray Prunus virginiana Chokecherry Purshia trident at a Bitterbrush Rosa acicularis Prickle rose Rosa woods ii Wood's rose Rosa parviflorus Thimbleberry Sambucus negra E ld erb erry Spiraea betulifolia White spirea Spiraea densifolia Mountain spirea S a lica cea e Populus tremuloides A spen Salix spp. W illow GRASSES AND GRASSLIKE PLANTS C yperaceae Carex geyeri Elk sed ge C arex spp. Sedge G ram ineae Agropyron cristatum Crested wheat grass Agropyron repens Quack grass Agropyron spicatum Bluebunch wheatgrass Agropyron smithii Bluestem wheatgrass Agrostis scabra Tickle-grass 125 Scientific Name Common Name Bonteloua gracilis B lue gram a Bromus carinatus Large rat brome Bromus commutât us Hairy cheat grass Bromus tectorum C heatgrass Calamagrostis canadensis Bluej oint Calamagrostis rubes cens P in e g ra ss Calamovilfa longifolia Sand g ra ss Cinna latifolia Drooping woodreed Danthonia californica California oat grass Danthonia unispicata Onespike oat grass Des champs ia danthonioides Annual hair grass Elymus glaucus Blue wildrye Festuca idahoensis Idaho fescue Festuca scab relia Rough fescue Hordeum iubatum Oxtail barley Koeleria cristata Ju negrass Oryzopsis hendersonii Little ricegrass Phleum pratense Common timothy Poa bulbosa Bulbous bluegrass Poa compressa Canada bluegrass Poa palustris Fowl bluegrass Setaria lutescens Yellow bristlegrass Stipa comat a Needle and thread Stipa occidentalis Western needlegrass Junaceae Juncus longistylis Rush APPENDIX B TABLE 20. Winter and summer activity centers and movement patterns of bighorn sheep Distance Standard Standard Map Distance from site Location diameter Location diameter Tag Sex Date Trap- Date coordinates from site of last of winter of winter of summer of summer No. marked site relocated of relocation of capture relocation center of area center of area (in miles) (in miles) activity (in miles) activity (in miles) 411 ? 6/18/73 B 9/ 4/73 R - 2 0 0.25 H-45 1 . 0 0 L-42 6 . 0 0 9/21/73 H-42 6 . 0 0 6.25 9/30/73 T-26 1 . 0 0 5.25 11/ 6/73 G-48 7.00 6.25 2/23/74 F-44 6 . 50 0.75 4/ 8/74 1-44 4. 75 2 . 0 0 4/11/74 1-39 5.25 0.75 4/17/74 G-48 7.00 2 . 0 0 Radio Î 6/21/73 A 7/ 7/73 R-20 7.25 1-39 2 . 0 0 Q-28 8 . 1 0 9/21/73 H-44 1 . 0 0 6 . 0 0 3/ 6/74 G-41 1. 50 0.50 3/ 9/74 G-41 1 . 0 0 0. 75 5/24/74 J-38 2.25 1.50 410 ? 6/22/73 A 9/17/73 H-39 2 . 0 0 Q-25 M-35 6.17 9/18/73 1-37 2. 50 0.50 10/15/73 V-13 9.00 6.75 12/10/73 Q-25 6 . 0 0 3.00 3/23/74 1-36 2 . 75 3.50 412 ? 6/24/73 B 7/14/73 G-48 7.25 S-23 1.41 K-39 4.49 7/21/73 R-20 0 . 0 0 7.25 3/ 6/74 Q-26 1. 50 1.50 3/ 8/74 S-19 0. 50 1.75 4/ 5/74 1-37 4. 75 5.00 tc 03 TABLE 20. (continued) Distance Standard Standard Distance Location Location Map from site diameter diameter Tag Date Trap* Date from site of winter of summer coordinates of last of winter of summer Xo. marked site relocated of capture center of center of of relocation relocation area area (in miles) activity activity (in miles) (in miles) (in miles) 4/ 8/74 J-37 4.75 5.00 4/11/74 H-37 4.75 5.00 4/14/74 1-38 4. 75 5.00 4/17/74 G-48 7.25 2. 50 413 d- 6/26/73 B 7/21/73 R-20 L-33 T-16 6.26 7/22/73 S-20 8/26/73 V-7 3. 50 3.50 9/ 7/73 V- 6 4,00 0.50 9/28/73 W-7 3. 50 0.75 10/15/73 G-44 6.75 1 0 . 0 0 3/ 8/74 R-22 0. 50 6.25 4/ 5/74 W-9 3.00 3.50 414 5 6/26/73 B 10/ 8/73 V-10 3.00 V-9 1.64 L-34 6.80 11/13/73 W-9 3.00 0.25 11/17/73 V-9 3.25 0.25 11/19/73 V-9 3.00 0 . 1 2 12/ 4/73 W-10 3.00 0 . 1 2 12/ 8/73 W-9 3.25 0 . 1 2 12/10/73 V-10 2.75 0.25 1/ 8/74 U-13 2 . 0 0 0.85 1/19/74 V-9 3.25 1 . 0 0 2/ 5/74 W-9 3.25 0 . 1 2 2/ 6/74 W-10 3.00 0.25 2/ 8/74 V-9 3.25 0 . 1 2 2/ 9/74 V-10 2.75 0.25 2/13/74 W-10 2.75 0.25 TABLE 20. (continued) Distance Standard Standard Distance Location Location Map from site diameter diameter Tag Date Trap- Date from site of winter of summer Sex coordinates of last of winter of summer No. marked site relocated of capture center of center of of relocation relocation area area (in miles) activity activity (in miles) (in miles) (in miles) 2/20/74 U- 1 2 2. 50 0.50 4/ 5/74 G-49 7.75 1 0 . 0 0 4/14/74 F-45 7.00 1 . 1 2 4/17/74 G-48 7.00 0.85 415 6/30/73 A 9/21/73 H-43 1 . 1 2 H-46 1.75 G-45 1.40 10/28/73 H-40 1.50 0. 50 2/ 6/74 G-43 0.85 0.50 2/10/74 F-49 0.75 1.50 3/ 9/74 G-44 0.75 1.25 4/ 5/74 H-49 0.50 1.40 4/17/74 G-48 0 . 0 0 0.60 416 $ 6/30/73 A 7/15/73 R-20 7.12 J-38 1.19 K-36 5.86 12/ 4/73 1-37 2 . 1 2 4.50 3/ 6/74 J-36 3.00 0.50 3/ 7/74 1-38 2,40 0.75 3/23/74 1-37 2.50 0,25 420 ? 7/ 1/73 B 7/19/73 G-48 7.00 V-13 1.50 Q-24 8.27 10/15/73 Ü-14 1.75 8 . 75 10/16/73 U-12 2. 50 0.75 11/28/73 V-10 2.80 0.30 427 cT 7/ 1/73 A 7/22/73 G-48 H-39 1.13 G-48 1.65 12/ 5/73 G-42 1.40 1.30 2/ 2/74 1-38 2. 50 1 . 1 2 2/ 6/74 G-41 1. 50 1 . 0 0 N3 00 TABLE 20. (continued) Distance Standard Standard Distance Location Location Map from site diameter diameter Tag Trap- Date from site of winter of summer Sex coordinates of last of winter of summer Xo. marked site relocated of capture center of center of of relocation relocation area area (in miles) activity activity (in miles) (in miles) (in miles) 2/ 9/74 1-36 2.60 1.25 4/ 5/74 H-49 0.50 3.25 4/14/74 F-46 0.75 1 . 1 2 428 = 7/ 4/73 A 10/28/73 H-40 1.50 L-38 1 . 0 0 J-39 4. 80 2/ 9/74 1-37 2.60 1 . 0 0 3/ 9/74 1-38 2.50 0 . 2 0 3/23/74 1-36 2.60 0.25 4/16/74 P-24 6 . 0 0 3.50 446 cf 7/ 4/73 A 2/ 9/74 T-19 7.60 M-34 8 . 2 0 J-38 9.25 2/23/74 F-48 0.65 8.25 3/23/74 G-50 0.65 0.50 4/ 5/74 F-47 0.50 0.50 4/14/74 1-37 2.60 3.00 4/17/74 1-39 1.80 0.75 5/11/74 V-9 10.15 8.25 435 d* 7/ 6/73 A 7/17/73 G-48 H-43 2.50 H-47 3.02 7/22/73 G-48 9/17/73 1-40 1.75 1,75 2/ 9/74 1-37 2.50 0.75 2/20/74 G-45 0. 50 1.25 2/23/74 F-48 0. 75 0.85 4/ 8/74 G-50 0.75 0.30 4/17/74 G-48 0 . 0 0 0.80 to CD TABLE 20. (continued) Distance Standard Distance Location Location Standard Alap from site diameter diameter Tag Date Trap- Date from site of winter of summer coordinates of last of winter No. marked site relocated of capture center of center of of summer of relocation relocation area (in miles) activity activity area (in miles) (in miles) (in miles) 445 7/10/73 12/ 4/73 1-37 2.60 Q-24 4. 74 1-43 6.88 21 9/74 T-19 7.60 5.25 2/20/74 S-22 6.25 0.75 3/ 6/74 S-19 7. 12 0.30 3/ 8/74 Q-21 6.80 0.30 3/23/74 F-47 0. 50 7.00 4/ 5/74 H-49 0. 50 0.25 4/ 8/74 F-50 0.75 0.25 447 7/10/73 7/22/73 G-48 H-45 1.91 N-31 8.10 9/ 4/73 R-23 7.00 7.00 9/16/73 G-44 0.85 6 . 50 9/21/73 H-42 1 . 0 0 0.50 10/16/73 T-18 7. 75 6.25 11/ 6/73 H-47 0 . 1 2 7.60 2/20/74 H-43 1.75 1.60 3/ 6/74 R-22 6.75 5.12 3/23/74 F-47 0. 50 6.75 4/ 8/74 U-17 8.35 8.35 4/13/74 S-20 7.35 0.85 4/14/74 U-16 8 . 50 1 . 0 0 436 7/11/74 10/11/73 X-20 8 . 0 0 J-39 3.70 K-39 8.62 11/ 6/73 H-47 0 . 1 2 7.85 12/ 4/73 1-37 2.60 2.50 2/ 9/74 T-19 7.50 5.12 2/20/74 H-45 0. 50 7.25 2/23/74 F-48 0.60 0.85 CÛ o TABLE 20. (continued) Distance standard Standard Distance Location Location Map from site diameter diameter Tag Trap- Date from site of winter of summer Sex Date coordinates of last of winter of summer marked site relocated of capture center of center of No. of relocation relocation area area (in miles) activity- activity (in miles) (in miles) (in miles) 3/ 6/74 K-35 3.00 3.60 3/ 7/74 1-38 2.40 0. 75 3/23/74 G-47 0.50 2.50 4/14/74 F-46 0.75 0.50 4/17/74 1-44 1.85 1.50 5/24/74 N-34 3.10 2 . 0 0 449 7/11/73 7/21/73 R-20 7.12 V-10 .67 J-41 6.28 1/ 2/74 U- 1 0 1 0 . 1 2 3.00 1/19/74 V-9 10.25 0.25 2/ 8/74 V-9 10.30 0 . 1 0 2/ 9/74 V-9 10.25 0 . 1 0 2/13/74 U-11 1 0 . 0 0 0.25 2/20/74 U-12 9. 50 0.60 4/ 5/74 H-49 0. 50 1 0 . 0 0 4/14/74 F-46 0. 70 1 , 1 2 174 7/14/73 7/22/73 R-20 7.00 J-39 3.19 0-2 9 8.05 8 / 8/73 G-48 0 . 0 0 7.00 2 / 2/74 1-38 2. 50 2.50 2/20/74 1-39 1. 90 0.50 3/ 6/74 L-33 3.50 1.25 4/ 8/74 1-16 8.25 4.80 4/13/74 R-19 7. 50 0.75 4/14/74 T-17 8 . 1 2 0. 70 213 7/22/73 9/ 4/73 R-20 7.00 N-31 5.59 J-41 5. 95 9/17/73 1-40 1.85 5.30 11/15/73 R-24 6 . 1 2 4.40 TABLE 20. (continued) Distance Standard Standard Distance Location Location Map from site diameter diameter Tag Date Trap- Date from site of winter of summer Sex coordinates of last of winter of summer No. marked site relocated of capture center of center of of relocation relocation area area (in miles) activity activity (in miles) (in miles) (in miles) 12/ 5/73 H-41 1. 50 4.85 1/20/74 1-37 2.60 1.25 2/ 2/74 Q-29 5.40 3.00 21 9/74 U-18 7.85 2. 50 2/13/74 S-19 7.65 0.25 2/20/74 H-46 0.40 7.25 3/ 7/74 1-40 1.65 1.30 3/ 9/74 G-45 0. 50 1.45 3/23/74 G-47 0.40 0.30 4/14/74 F-46 0.65 0. 50 4/17/74 1-39 2 . 0 0 1.60 231 7/22/73 2/ 4/74 1-37 2.60 1-41 2.83 H-42 2.15 2/ 6/74 1-37 2.60 0 . 1 2 2/ 9/74 1-36 2.70 0 . 1 0 2/20/74 H-45 0. 50 2.25 3/ 9/74 G-41 1.50 1 . 0 0 3/23/74 J-36 2.65 1.25 tc 25 N Fig. 18. Grid map showing winter and summer activity centers and movement patterns of bighorn sheep. CO CO APPENDIX C TABLE 21. Annual horn growth in bighorn rams {in millimeters) Basal Year of growth Total Age of circum length ram ference 1 st 2 nd 3rd 4th 5th 6 th 7th 8 th (yrs.) L RL RL R L R LRL RL R LR L R L R 3.5 880 8 8 6 406 400 165 153 303 311 234 254 178 168 3.5 813 799 385 385 175 178 311 308 184 185 143 131 3.5 787 762^ 385 373 127 106^ 2 90 289 2 1 1 207 159 160 3.5 762 759 387 381 152 155 2 54 257 197 193 159 154 3.5 807 820 375 375 186 204 287 263 185 185 159 168 4. 5 861 859 401 404 127 132 257 255 185 178 165 162 127 132 5. 5 939^ 948^ 397 3 91 70^ 70^ 299 299 194 191 156 159 124 124 96 105 7 7 a 6 . 5 903^ 910^ 416 416 80^ 267 266 224 224 150 151 45 36 59 64 78 92 4.5 860^ 8 6 6 ^ 401 394 51^ 61^ 283 299 185 2 0 0 178 175 143 131 5. 5 870^ 877^ 391 391 58^ 60^ 229 231 2 1 2 2 1 0 169 175 132 127 70 74 2.5 633 636 349 352 146 146 305 305 182 185 4. 5 854 834 432 432 170 165 226 2 2 2 187 182 137 134 134 131 4.5 940 966 413 413 4.5 826 828 391 388 168 172 236 236 174 185 140 140 108 95 6 . 5 931^ 9 3 7 a 381 384 2 0 ^ 0 2 92 289 172 173 150 156 114 118 1 0 0 1 0 2 83 89 5. 5 9 4 7 a 927^ 381 387 84 80 2 92 289 207 204 162 159 1 2 2 115 80 80 7.5 953 1,016 368 371 0 ^ 0 ^ 2 0 0 ^ 289 227 2 2 2 197 185 1 2 1 115 89 8 6 61 64 58 55 7. 5 910 889 381 375 0 ® 0 ^ 299 2 99 197 196 146 142 108 105 70 6 6 51 48 39 33 6 . 5 890 924 368 368 61^ 83^ 274 2 74 178 178 80 80 64 70 134 134 1 0 2 1 0 2 Animals shot from original herd prior to 1946 3. 5 513 518 286 289 77 82 240 242 140 143 56 51 6 . 5 762 759 356 353 115 115 236 233 152 153 115 115 77 76 54 51 13 16 6 . 5 813 826 359 362 52^ 64^ 255 254 162 161 124 123 83 8 6 76 78 61 60 ^Indicates broken or broomed horn tips. oc 4k