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An ecological study of California bighorn sheep Ovis canadensis californiana (Douglas) in southern British… Blood, Donald Arthur 1961

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i  AW ECOLOGICAL STUDY OF CALIFORNIA BIGHORN SHEEP OVIS CANADENSIS CALIFORNIANA (DOUGLAS) IN SOUTHERN BRITISH COLUMBIA  by  DONALD ARTHUR BLOOD B. Sc., U n i v e r s i t y o f B r i t i s h Columbia, 1959  A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE  REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE  i n t h e Department of ZOOLOGY  We a c c e p t t h i s t h e s i s as conforming t o t h e required standard  THE  UNIVERSITY OF BRITISH COLUMBIA September, 1961  In presenting  t h i s thesis i n p a r t i a l f u l f i l m e n t of  the requirements for an advanced degree at the University of B r i t i s h Columbia, I agree that the Library s h a l l make i t f r e e l y available f o r reference  and study.  I further agree that permission  for extensive copying of t h i s thesis f o r scholarly purposes may granted by the Head of my Department or by his  be  representatives.  It i s understood that copying or publication of t h i s thesis f o r f i n a n c i a l gaixi s h a l l not be allowed without my written permission.  Donald A. Blood  Department of  Zoology  The University of B r i t i s h Columbia, Vancouver 3, Canada. Date  September 6,  196i  ii ABSTRACT There have been alarming d e c l i n e s i n the number o f C a l i f o r n i a b i g h o r n sheep i n t h e Similkameen r e g i o n o f B r i t i s h Columbia s i n c e the l a t t e r p a r t of  the nineteenth century.  Present c o n f l i c t f o r food supply with  s t o c k makes f u r t h e r herd r e d u c t i o n imminent.  domestic  T h i s study was  i n i t i a t e d to  g a t h e r sound e c o l o g i c a l d a t a on w h i c h to base management and  conservation  p r a c t i s e s f o r t h e C a l i f o r n i a b i g h o r n sheep i n B r i t i s h Columbia and t o determine p o p u l a t i o n s t a t u s o f the A s h n o l a The A s h n o l a h e r d was 196L  The  patterns.  s t u d i e d i n t h e f i e l d from May  I960 through  June  study a r e a i s d e s c r i b e d on t h e b a s i s o f broad s o i l and v e g e t a t i o n L i n e p o i n t t r a n s e c t s were employed to determine b o t a n i c a l  composition from age  herd.  o f important winter ranges.  The  sheep p o p u l a t i o n i s a n a l y s e d  and sex r a t i o s and age s t r u c t u r e d a t a .  by c o l l e c t i n g remains, i n the f i e l d ,  Age  s t r u c t u r e was  determined  o f sheep which d i e d o f n a t u r a l c a u s e s .  N a t a l i t y and m o r t a l i t y r a t e s from t h e above sources i n d i c a t e t h a t the is  relatively stable.  herd  Census d a t a s u b s t a n t i a t e s t h i s o b s e r v a t i o n .  F a c t o r s l i m i t i n g p o p u l a t i o n i n c r e a s e are e v a l u a t e d w i t h emphasis on competition f o r food.  P r e d a t i o n , a c c i d e n t s and h u n t i n g  to be p r e s e n t l y l i m i t i n g herd i n c r e a s e . was  are not  considered  I n c i d e n c e o f p a r a s i t i s m i n the  i n v e s t i g a t e d by p o s t mortem examination  and f e c a l a n a l y s i s .  No  d i r e c t l y a t t r i b u t a b l e to p a r a s i t i s m were noted d u r i n g the s t u d y .  herd  deaths  Grazing  by c a t t l e appears t o be t h e p r i m a r y l a n d use p r e s e n t l y t h r e a t e n i n g the w e l f a r e o f the h e r d .  B i g h o r n s h e e p - c a t t l e c o m p e t i t i o n i n v o l v e s s p r i n g and  f a l l u t i l i z a t i o n by c a t t l e o f sheep w i n t e r r a n g e s .  D i r e c t and  indirect  o b s e r v a t i o n o f animal d i s t r i b u t i o n , f o o d h a b i t a n a l y s i s and e x c l o s u r e p l o t t e c h n i q u e have been employed to e v a l u a t e the c o m p e t i t i v e i n t e r a c t i o n , . though c o m p e t i t i o n was  slight i n  Al-  i960, f o o d s h o r t a g e r e s u l t i n g from c a t t l e  iii g r a z i n g and o c c a s i o n a l s e v e r e snow c o n d i t i o n s i s suggested as t h e f a c t o r l i m i t i n g herd i n c r e a s e o A s p e c t s o f herd b i o l o g y and b e h a v i o r  s u c h as r u t t i n g , lambing,  and s o c i a l o r g a n i z a t i o n a r e a l s o d e s c r i b e d . recommendations a r e b r i e f l y  discussed.  migration  Management c o n s i d e r a t i o n s and  iv TABLE OF CONTENTS INTRODUCTION AND ACKNOWLEDGEMENTS  Page ••  3  DESCRIPTION OF THE AREA Location. « . « o . . Physiography  1  •  3 3  and S o i l s .  Climate..  •  Vegetation Patterns  •  5 5 9  The W i n t e r - S p r i n g Ranges South S l o p e  10  Juniper Slope  13  Starvation-Flatiron R e l i c t Slopes «  *•  ±k  «  15  C r a t e r Mountain.  16  Lower A s h n o l a R i v e r . . . .  17  P a u l Creek.  17 18  HISTORICAL ACCOUNT Origin o f the Population Similkameen Herds Range Use.  «  •  18  «•.  18  o  2k  PRESENT DISTRIBUTION AND NUMBERS.  2$  ANALYSIS OF THE POPULATION  26  Rate o f P o p u l a t i o n I n c r e a s e  26  Rate o f P o p u l a t i o n Replacement  35"  Dispersal LIMITING FACTORS..,  ij.0 1|1 l.\2  Food Range Forage C o m p e t i t i o n , , . .  k2  V  Competition w i t h C a t t l e  43  G e n e r a l P a t t e r n o f Range Overlap  43  Areas Grazed on Winter Range  45  Forage P r e f e r e n c e s  47  •  Degree o f U t i l i z a t i o n  56  Summary  59  C o m p e t i t i o n w i t h Deer  60  • o.  C o m p e t i t i o n w i t h Horses  63  Animal Use o f S e v e r a l Ranges  64  Forage P r o d u c t i o n and C a r r y o v e r  66  P a r a s i t e s and Disease  ••••  80  Predation. Accidents.  73  • •. •  83  Hunting  83  BEHAVIOR  89  M i g r a t i o n and Movements  89  Grouping  95  and S o c i a l Dynamics  R u t t i n g and Lambing  98  MANAGEMENT  101  DISCUSSION  108  SUMMARY  114  APPENDIX TABLES.  118  LITERATURE CITED  124  vi. LIST OF TABLES Number  Page  1.  Climatic data.  2o  Recent  3.  Lanib-and y e a r l i n g - t o - e w e r a t i o s ,  4.  Lanib-and y e a r l i n g - t o - e w e r a t i o s , west o f A s h n o l a R i v e r .  31  5.  Lamb-to-ewe r a t i o s : p a r t i a l l y c l a s s i f i e d counts  31  6.  Ram-to-ewe r a t i o s , 1!?6<).  35  7.  L i f e table  38  8.  Age  and sex o f sheep d y i n g on A s h n o l a ranges  40  9o  E f f e c t o f s l o p e on c a t t l e and sheep d i s t r i b u t i o n  46  10.  6  •  census f i g u r e s f o r A s h n o l a b i g h o r n sheep  23 30  e a s t of A s h n o l a R i v e r  U t i l i z a t i o n c l a s s e s f o r South S l o p e a f t e r summer.grazing  by 46  cattle 11.  C a t t l e and sheep f o r a g e p r e f e r e n c e s on South  Slope  (grazed stem t e c h n i q u e )  50  12.  B i g h o r n sheep w i n t e r f o o d h a b i t s from t r a i l i n g  51  13.  Composition o f 6 rumen samples o f b i g h o r n sheep  52  14.  S p r i n g f o o d h a b i t s o f b i g h o r n sheep on South S l o p e  53  l5»  U t i l i z a t i o n c l a s s e s f o r South S l o p e a f t e r b o t h sheep  and 58  c a t t l e use 16.  Composition  o f 3 rumen samples o f mule deer  17o  L o c a t i o n s o f l a r g e mammal e x c l o s u r e p l o t s . . .  l8«  Forage y i e l d o f f e n c e d and unfenced p l o t s  19.  P r o t o s t r o n g y l i n l a r v a e o c c u r r e n c e and i n f e c t i o n  62 68 <•  70  •  76  20.  S e a s o n a l p r o t o s t r o n g y l i n l a r v a e o c c u r r e n c e i n sheep d r o p p i n g s . .  76  21.  P a r a s i t e s o f t h e A s h n o l a b i g h o r n herd  79  22.  L e g a l sheep h a r v e s t i n A s h n o l a r e g i o n ,  23.  S p r i n g m i g r a t i o n o f sheep from South S l o p e  24.  S p r i n g lamb counts f o r South S l o p e  r a t e s by  and sex groups o f b i g h o r n sheep  1947-1960.  age  •  88 93 100  viii LIST OF ILLUSTRATIONS To Figure  follow Page  1.  South s i d e o f C r a t e r Mountain,,  ..  7  2,  Lodgepole p i n e s u c c e s s i o n i n a b u r n  «•«  7  3»  Aspen p a r k l a n d a r e a  8  U.  Douglas f i r - p i n e g r a s s zone  8  5.  Douglas f i r - w h e a t g r a s s a s s o c i a t i o n .  8  6.  Shrub growth below J u n i p e r S l o p e  8  7o  Map o f A s h n o l a b i g h o r n sheep w i n t e r ranges  8.  Panoramic view o f South S l o p e  •  10  9 & 1 0 . E r o s i o n on South S l o p e . .  , 10  1 1 & 12. Snow c o v e r on South S l o p e and J u n i p e r S l o p e i n Feb., I960.. 13. lk  10  Bar graph showing cover c l a s s e s on South S l o p e  lU lU  & 1 5 . The S t a r v a t i o n F l a t s range  1$  1 6 & 1 7 . C r a t e r Mountain w i n t e r and s p r i n g sheep ranges  16  18«  Bar g r a p h o f range c o n d i t i o n and t r e n d f a c t o r s  17  19•  Map o f b i g h o r n sheep and c a t t l e d i s t r i b u t i o n  2$  20.  Graph o f lamb and y e a r l i n g r a t i o t r e n d s . . . . . . . .  21.  M o r t a l i t y and s u r v i v o r s h i p curves  39  22.  Bar graph comparing summer c a t t l e d i e t w i t h season b i g h o r n sheep d i e t s  53  23.  ».  32  B a r graph o f u t i l i z a t i o n c l a s s e s f o r South S l o p e a f t e r c a t t l e u s e and combined sheep and c a t t l e u s e  57  2k*  Snow depths i n t h e South S l o p e r e g i o n  58  25.  A n i m a l d r o p p i n g counts on s e v e r a l r a n g e s . . . .  64  260  Ungulate u s e o f s e v e r a l sheep w i n t e r ranges  65  27.  P l a n view o f e x c l o s u r e p l o t  68  2 8 & 2 9 . Views o f e x c l o s u r e p l o t s on h e a v i l y and l i g h t l y g r a z e d areas o f South S l o p e  70  viii  30.  Exclosure plot no. 2 on Juniper Slope  70  31.  Exclosure plot no. 6 on the lower bench of South Slope  70  32 & 33. Exclosure plots 9 and 10 on Crater Mountain  71  3k»  Age distribution of kk rams harvested in the Ashnola....o..  88  3$o  View of alpine ranges  91  36.  Bar graph showing seasonal changes in grouping of  37.  bighorn sheep.  96  Frequency distributions of sheep group sizes.  98  38 & 39. Lambing aid escape terrain  »  99  1 INTRODUCTION AND ACKNOWLEDGEMEl'JTS Approximately twelve hundred C a l i f o r n i a bighorn sheep presently e x i s t i n B r i t i s h Columbia.  These are d i s t r i b u t e d i n several disjunct herds.  The Ashnola herd was chosen f o r intensive study because of i t s proximity to Vancouver and i t s r e l a t i v e a c c e s s i b i l i t y . 200  The Ashnola River l i e s about  miles east o f Vancouver and can be reached by a f i v e to s i x hour  drive.  About 250 animals make up the herd.  The majority of these bighorn  sheep are concentrated , during the winter, on an area of l e s s than f i v e square m i l e s .  None o f the winter range units are more than a three hour  walk from the Ashnola road.  Light snowfall permits ready access of the  winter ranges without snows hoes.  The open nature of the f o r e s t and numer-  ous t r a i l s f a c i l i t a t e the use o f horses during the summer. Approximately 120  C a l i f o r n i a bighorn sheep have been k i l l e d l e g a l l y  i n the Okanagan-Similkameen region of B r i t i s h Columbia during the past 50 years.  Despite t h i s small hunting removal sheep populations have f a i l e d  to show any marked increase. Realizing that good conservation practices require more than r e s t r i c t i o n o f l e g a l hunting, the B r i t i s h Columbia Game Department encouraged surveys of the Okanagan-Similkameen bighorn herds which were i n i t i a t e d by Dr. I . M T. C  Cowan o f the University of B r i t i s h  Columbia i n 195*0 • A f t e r 1955,yearly trend counts were made and harvest information gathered by personnel o f the B r i t i s h Columbia Game Department. F i e l d aspects o f t h i s study began i n May I960 and continued u n t i l June 1 9 6 1 . Major objectives o f t h i s i n v e s t i g a t i o n were to gather information concerning the range requirements of the Ashnola bighorn herd, to study and analyze mortality patterns and factors affecting productivity, to gain some knowledge o f migration and patterns of s o c i a l organization i n the C a l i f o r n i a bighorn and to make accurate censuses as a basis f o r management of the herd.  Generally speaking, the ecology of the herd was investigated.  2  Many o f the facts presented should contribute to a management program designed to increase the present number o f bighorn sheep within the l i m i t s of range capacities, at the same time permitting maximum harvest consistent with that g o a l .  Relationships other than those most d i r e c t l y related  to p r a c t i c a l management were also explored, and are most valuable as a basis of comparisons with other herds, races or species of bighorn sheep i n different l o c a l i t i e s . I am indebted to Dr. I . MT.  Cowan of the Department of Zoology,  University o f B r i t i s h Columbia,who supervised the study.  Dr. J . Hatter  and E. ¥. Taylor of the B r i t i s h Columbia Game Department contributed game check s t a t i s t i c s and made many u s e f u l suggestions. Arthur Bailey who  Special thanks are due  assisted with the f i e l d work during the summer o f I960.  Mr. Herb Clarke of Keremeos, B r i t i s h Columbia, through h i s long associat i o n with the Ashnola herd, was able to make many time saving suggestions. The use o f Mr. Clarke's cabin at Ashnola Forks has been e s p e c i a l l y appreciated. Dr. J . Adams, Department o f Zoology, University of B r i t i s h Columbia assisted i n the i d e n t i f i c a t i o n of endoparasites and with f e c a l examinations.  Professor George J . Spencer and Mr. Robert Drake, also of the  above department, i d e n t i f i e d ectoparasites and s n a i l s r e s p e c t i v e l y .  Dr. V.  J . Krajina, Department of Botany, University of B r i t i s h Columbia assisted with plant i d e n t i f i c a t i o n s . f u l l y acknowledged.  The assistance of a l l these people i s grate-  F i n a n c i a l assistance was provided by a National  Research Council bursary i n 1 9 5 9 - 6 0 and studentship i n 1 9 6 0 - 6 1 and by a research grant i n the Department of Zoology, University o f B r i t i s h Columbia.  The f i e l d assistant was supplied by the B r i t i s h Columbia Game  Department.  3 DESCRIPTION OF THE AREA Location The p r i n c i p a l study area l i e s immediately  adjacent the  49th  parallel  of l a t i t u d e , and i s bounded on the vrest, north, and east by the Similkameen River.  The intensive part o f the study took place on the lower watershed  of the Ashnola River about ten miles from i t s confluence with the Similkameen River.  The Ashnola bighorn herd presently occupies an area not l a r g e r  than two hundred square miles. Physiography and S o i l s The Ashnola area i s one o f topographical t r a n s i t i o n , being located where the southwestern edge of the i n t e r i o r plateau intergrades with the Cascade Mountains.  Where i t i s developed, the plateau surface l i e s at  about 5*500 feet i n elevation, sloping downward i n a northerly d i r e c t i o n . Locally, the Okanagan Mountains i n t e r r u p t the plateau surface and several peaks reach 8,500 feet i n elevation. These higher mountains provide summer range f o r the bighorn herd. precipitous.  Southward the country becomes more  The Ashnola River flows i n a northeasterly d i r e c t i o n through  a narrow v a l l e y deeply dissecting the plateau which l i e s about 2,500 f e e t above i t .  The winter bighorn range i s found c h i e f l y on southerly exposed  parts of the v a l l e y between the plateau and the r i v e r . Some of the lower slopes and f l o o r s of the main v a l l e y s display terrace formations that represent o l d r i v e r f l o o d p l a i n s and a l l u v i a l fans, however neither these nor the modern flood plains are extensive i n area. Granitic rocks are common i n the area.  These arose during the great  plutonic i n t r u s i o n which commenced i n J u r a s s i c times and which resulted i n the f i r s t great elevation of the coast range (Brink, and Farstad 1949).  The area was extensively glaciated during the Pleistocene, and the l a s t or Wisconsin g l a c i a t i o n erased or buried most of the traces of e a r l i e r glacial activity.  The s o i l s of the plateau and v a l l e y slopes consist  generally of g l a c i a l t i l l , boulder clay, and other i c e transported debris. The terraces on the other hand, often contain well sorted m a t e r i a l . Four great s o i l types occur within the range o f the Ashnola sheep herd according to the c l a s s i f i c a t i o n of Rowles (19U9). f o r e s t , alpine, and azonal.  These are grassland,  Since most of the true grasslands of t h i s  area occur below 3000 feet i n elevation, the Ashnola sheep are not commonly found on them.  The upper grassland of Tisdale (19U7) associated  with black earth s o i l s i s used somewhat by sheep during winter months however, and the extensively used edaphic climax grassland winter ranges at higher elevations (3000 to 6000 feet)probably have similar s o i l s . Forest s o i l s are commonest i n the area, the v a l l e y slopes consisting of yellowish-brown podsolic s o i l s and the plateau surface c h i e f l y o f greywooded s o i l s .  The brown podsolic s o i l s are c h a r a c t e r i s t i c of the d r i e r  more open f o r e s t s . sheep.  These open forests are used moderately by the bighorn  The grey-wooded s o i l s , found a l t i t u d i n a l l y above the podsols and  below the alpine s o i l s , are l a r g e l y uninvestigated and unsurveyed.  In  the southern I n t e r i o r of B r i t i s h Columbia they form a complex consisting of shallow stony g l a c i a l d r i f t and rock outcrop. these s o i l s are acid and highly leached.  Under dense tree cover  L i t t l e Ashnola sheep habitat  f a l l s on the l a t t e r s o i l type although c e r t a i n organic azonal s o i l s i n higher forested areas may be used more extensively. The alpine s o i l s are of the dry alpine type (Rowles op. c i t . ) and underly much of the sheep summer range.  Unstable s o i l s such as talus slopes are also common at  both high and low elevations.  5 Climate The climate i s determined to a large extent by the presence of a mountain b a r r i e r to the west and by the rugged topography of the region itself.  The whole area i s r e l a t i v e l y dry because of the "rain shadow"  e f f e c t of the Coast Mountains.  In addition, l o c a l climate i s strongly  affected by differences i n elevation and exposure.  In the southern  I n t e r i o r Plateau region i n general, p r e c i p i t a t i o n increases markedly with increased a l t i t u d e , while evaporation and a i r and s o i l  temperatures  decrease (Spillsbury and Tisdale 19hh)• The area f a l l s l a r g e l y within the southwestern i n t e r i o r v a l l e y s and low plateau c l i m a t i c d i v i s i o n o f Chapman (1952), having a decidedly cont i n e n t a l climate with p r e c i p i t a t i o n t o t a l s generally l e s s than twenty inches.  The more exposed higher sections have a Dfb type of climate^  while the v a l l e y s r e f l e c t the lower p r e c i p i t a t i o n and warmer summers with Dsa and Bsk according to the Koppen c l a s s i f i c a t i o n (Chapman op. c i t . ) . The annual p r e c i p i t a t i o n cycle shows two seasonal maxima. A long maximum of moderate p r e c i p i t a t i o n (generally snow) occurs during the winter months, while a short but more intense maximum occurs i n l a t e May and  throughout  June. Since a l t i t u d i n a l climatic variations profoundly a f f e c t seasonal d i s t r i b u t i o n and behavior of the bighorn sheep, data f o r representative stations are presented i n Table 1.  Although neither o f the stations are  within the Ashnola watershed, they are both very close and both within the former range o f bighorn sheep i n the Similkameen region.  Vegetation Patterns The natural vegetation r e f l e c t s the great v a r i a t i o n i n topography, climate, and s o i l s .  Forest occupies the greater part of the region with  6  TABLE 1 CLIMATIC DATA FOR REPRESENTATIVE STATIONS IN THE SIMILKAMEEN REGION OF BRITISH COLUMBIA.  Station  Range Type  Keremeos Nickle Plate  Grassland Spruce-fir  Elevation (feet) 1,165 5,800  Mean Tempo Jan. July (deg. F)  Av. Ann. Precip. (inches  2 5 71 17 54  9*8  Av. Annual Snowfall (inches) 23.6  145.5  grassland and alpine tundra making up the remainder. mostly occupy the main valleys at elevations below  The grasslands  2,500  feet but on south-  erly exposed mountain slopes may extend to considerable elevations and even merge with the alpine grassland (Figure 1 ) .  Due to the great r e l i e f  of the area much of the vegetation occurs i n a series of elevational bands which can be variously classified as biotic areas (Monro and Cowan  1947),  bioclimatic zones (Krajina 1959), range types (Tisdale et. a l 1 9 5 4 ) or forest regions (Rowe 1959). The grasslands belong to the bunchgrass type of the Pacific Northwest. Most of the non-alpine grassland occuring within the range of the Ashnola bighorn herd falls into the wheatgrass-bluegrass wheatgrass-fescue  zones of Tisdale  (1947).  (middle grassland) and  Bluebunch wheatgrass (Agropyron  spicatum var. inerme) is the principal grass of the region and i s a dominant i n both zones although the associated species differ considerably. The wheatgrass-bluegrass zone occurs at elevations of about feet.  2,00  to  4,000  The vegetation, where not altered by misuse, consists mainly of  bluebunch wheatgrass, Sandberg bluegrass (Poa secunda) and a number of forbs.  The bluegrass i s often not noticeably abundant.  Sagebrush  i s absent o r rare and the only common shrub i s rubber rabbitbrush (Chrysothamnus nauseosus), even t h i s being rather l o c a l l y d i s t r i b u t e d .  Where  heavily grazed the wheatgrass may be l a r g e l y replaced by cheatgrass (Bromus tectorum) and weedy f o r b s . The wheatgrass-fescue  zone occurs l a r g e l y above the  3,500 foot  elev-  ation i n the Ashnola region and on southerly exposed slopes may extend upward to merge with subalpine grassland at  6,000 feet  i n elevation.  This  i s the dominant vegetation type o f the edaphic climax grassland areas which form the majority o f the sheep wintering ranges i n the area.  The p r i n c i p a l  climax species are bluebunch wheatgrass, Idaho fescue (Festuca Idahoensis) and Junegrass  (Koeleria c r i s t a t a ) •  and chamaephytes.  In addition there are numerous forbs  This zone w i l l be discussed more f u l l y when the winter  sheep ranges are described. The forested areas f a l l n a t u r a l l y into three zones — Douglas f i r and spruce-pine — pine-bunchgrass,  ponderosa pine,  which correspond roughly with the ponderosa  I n t e r i o r Douglas f i r and subalpine Engelmann spruce-  sub alpine f i r biocliraatic zones o f Krajina (op. c i t . ) . . zone i s not w e l l developed i n the Ashnola region.  The ponderosa pine  I t occurs mainly as a  fringe below the Douglas f i r zone along the lower reaches o f the Ashnola River.  The t r a n s i t i o n between the ponderosa pine and Douglas f i r types  i s more extensive than the pine zone i t s e l f , the f i r being found commonly down to the 1,500 reaching  foot l e v e l on north slopes and scattered pine trees  3,800 feet  i n elevation on warm southerly exposed slopes.  Most o f the bighorn winter-spring ranges i n t h i s region f a l l i n a l l y *ri.thin the extensive Douglas f i r zone.  altitud-  The climax tree cover consists  mainly o f I n t e r i o r Douglas f i r (Pseudotsuga menziesii var. glauca) but, due to widespread f i r e s , a large part o f the zone i s now occupied by lodgepole pine (Pinus contorta var. l a t i f o l i a ) (Figure 2 ) . Aspen (Populus tremuloides)  FIGURE 1. South side of Crater Mountain with Starvation Flats i n foreground. Continuous grassland can be seen from the alpine zone to the valley floor. Most of the open slopes are edaphic climax grassland areas within the Douglas f i r and spruce zones. The mountain peak reaches 7,500 f t . i n elevation.  FIGURE 2 . This northerly exposed slope which was burned i n the 1930's i s now thickly repopulated with lodgepole pine. Fallen snags make the area impenetrable for l i v e stock. Such burned over areas are common i n the Ashnola. A few remnants of the Douglas f i r forest remain on the crest of the ridge up to 5,700 f t . i n elevation.  8 i s not as commonly found i n f i r e successions i n t h i s area as elsewhere i n the Southern I n t e r i o r , but i s developed as an edaphic climax parkland type on parts o f Crater Mountain between (Figure 3 ) .  U,000  and  5>500  feet i n elevation  On dry s i t e s , u s u a l l y bordering grassland areas, Rocky Moun-  t a i n juniper (Juniperus scopulorum) i s a common t r e e . Over much o f the Douglas f i r zone the tree stand i s r e l a t i v e l y open, and there i s a moderate undercover o f grasses, herbs and shrubs.  The  p r i n c i p a l grass i s pinegrass (Calamagrostis rubescens) (Figure h) but on steep south facing slopes at lower elevations bluebunch wheatgrass may dominate (Figure 5 ) . Broadleaved plants are not abundant i n t h i s zone but include fleabanes (Erigeron sp.), locoweed (Oxytropis), paintbrush ( C a s t i l l e j a ) , columbines (Aquilegia formosa) and shooting stars (Dodecatheon)• The commonest shrubs are squaw current (Ribes cereum) and s o o p o l a l l i e (Sheperdia canadensis), while willows (Salix sp.) and Saskatoon berry (Amelanchier  a l n i f o l i a ) occur l e s s frequently. Figure 6 shows abundant  growth o f squaw current and s o o p o l a l l i e i n an o l d burn at the elevation.  5000  foot  The t h i r d forest zone i n t h i s area i s a spruce-pine zone s i t u -  ated- above the Douglas f i r zone i n a climate that i s cool and r e l a t i v e l y moist.  The climax dominant i s Engelmann spruce (Picea engelmanni) which  occurs commonly from  5,500  to  7,000  feet i n elevation, but extends to  lower elevations along streams and on damp northerly exposed slopes. Alpine f i r (Abies lasiocorpa), also a climax dominant throughout much o f the i n t e r i o r subalpine forest region was not seen to occur within the range of the Ashnola bighorn herd, but seems to be replaced by lodgepole pine which occurs commonly to timberline. Alpine l a r c h (Larix l y a l l i i ) occurs i n the southern part o f the region at timberline on the north sides o f the highest mountains.  Where tree cover i s dense the undergrowth consists  FIGURE 3. This aspen parkland area o f Crater Mountain i s very productive and supports heavi e s t c a t t l e grazing west o f the Ashnola River. Bighorn sheep use the aspen range type l i t t l e but frequent the steeper bunchgrass slope i n the background during the winter.  •  I  FIGURE i ; . Douglas f i r - p i n e grass zone a t 5 0 0 0 f t . e l e vation, near Starvation F l a t s . The abundant growth o f pinegrass remains succulent u n t i l well into August. L i t t l e use i s made o f t h i s range type by either c a t t l e or bighorn sheep.  FIGURE 5« On t h i s s t e e p s o u t h e r l y exposed s l o p e , Douglas f i r forms open stands and t h e dominant undergrowth i s b l u e b u n c h w h e a t g r a s s . The area p i c t u r e d i s 3 , 5 0 0 f t . i n e l e v a t i o n and was n o t g r a z e d by c a t t l e o r b i g h o r n sheep d u r i n g the s t u d y . Use b y deer i s s l i g h t .  FIGURE 6. T h i s burned a r e a (5000 f t . e l e v a t i o n ) s u p p o r t s abundant growth o f squaw c u r r e n t and l e s s e r amounts o f s o o p o l a l l i e . A l t h o u g h shrub growth i s n o t common on Ashn o l a r a n g e s , b o t h s p e c i e s show l i t t l e e v i d e n c e o f u t i l i z a t i o n . A r e a shown i s a t lower edge o f J u n i p e r S l o p e .  9 mainly o f blueberry (Vaccinium scoparium), while on warmer more open s i t e s shrubby c i n q u e f o i l ( P o t e n t i l l a fruticosa ) and kinnikinnick (Arctostaphylos uva-ursi) are common. Meadows within t h i s zone consist l a r g e l y o f sedges (Carex sp.), woodrush (Luzula), lupine (Lupinus), intermediate oatgrass (Danthonia intermedia) and spike trisetum (Triseturn spicatum). The alpine zone i n t h i s region commences at 6 , 8 0 0 to 7000 feet i n elevation, and i s probably the d r i e s t alpine area i n the province. The climax vegetation i s p r i n c i p a l l y a grass-sedge complex with alpine sheep fescue (Festuca ovina var. brachyphylla) and alpine bluegrass (Poa alpina) dominating the higher slopes.  The lower slopes have many species i n com-  mon with the subalpine meadows.  There i s a notable dearth o f ericaceous  shrubs, although heathers (Phyllodoce and Cassiope) occur s p o r a d i c a l l y . Dwarf willow (Salix n i v a l i s ) and white dryas (Dryas octopetala) form a t h i n mat on rocky areas. Summer range o f the bighorn sheep f a l l s l a r g e l y i n the alpine zone and i n the alpine-subalpine f r i n g e .  During early f a l l some use i s made o f  the true subalpine (spruce-pine) zone, e s p e c i a l l y by rams harassed by hunters. The Winter-Spring Ranges In B r i t i s h Columbia the winter ranges o f montane ungulates such as the C a l i f o r n i a bighorn sheep, since they, are so much more r e s t r i c t e d i n extent than the summer ranges, are the key to herd management.  I f adequate winter  range i s not available no amount o f summer range w i l l save the population from starvation, p a r t i c u l a r l y during years o f deep snow.  The winter range  of bighorn sheep i n the Ashnola i s considerably smaller than the summer range, p a r t i c u l a r l y i f only the preferred grassland areas are included. Management o f these ranges i s complicated by the f a c t that they are also  10 used as domestic stock ranges during the summer. Ashnola bighorn sheep wintering ranges present a s t r i k i n g example o f the  e f f e c t o f southerly slope exposure on climax plant development.  Accord-  ing  to Daubenmire (1959), a slope o f as l i t t l e as 5 degrees toward the pole  reduces s o i l temperature approximately as much as 300 miles o f l a t i t u d e i n the  same d i r e c t i o n .  D i r e c t l y or i n d i r e c t l y as a r e s u l t o f t h i s slope-inst3la-  t i o n r e l a t i o n s h i p , plants adapted to the warm dry v a l l e y f l o o r extend highest i n the mountains on those slopes and ridges oriented to get the maximum insolation. up to  Bluebunch wheatgrass f o r example, commonly forms climax stands  6000 feet i n elevation on steep southerly exposed slopes i n the Ash-  nola d i s t r i c t . South Slope The south slope range (Figures 7 and 8) i s the most important winter range i n the Ashnola, wintering at l e a s t one h a l f o f the t o t a l sheep population.  I t i s located on the north side o f Juniper Creek, a t r i b u t a r y o f  Ewart Creek (South Fork o f the Ashnola R i v e r ) .  6,200 feet i n elevation and averages  20  to  I t l i e s between kOOO and  25 degrees i n slope.  The steep  ascent i s broken by a broad bench, a large basin, and several rock escarpments.  The range extends along the v a l l e y f o r approximately two miles,  and covers about 1 0 0 0 acres.  The steeper areas are heavily terraced and  erosion i s common. On July  31,  I960  I had the opportunity to observe a cloudburst o f a  s e v e r i t y which, according to l o c a l residents, occurs only once i n 10 to 2 0 years.  One gulley, i n places over 6 feet deep was washed i n South Slope  i n addition to many smaller gulleys (Figure 9 ) . deposited on the lower bench.  Much rock and s o i l was  Sheet erosion was also prevalent (Figure 1 0 ) .  Two perenial springs e x i s t on south slope, and several streams are nearby.  Ideal escape t e r r a i n i s found i n the form o f a series o f broken  Seat  FIGURE 8.  Panoramic view of the South Slope range, w i t h Douglas f i r s c a t t e r e d along the draws. end of the slope ( l e f t ) r e c e i v e s h e a v i e s t c a t t l e use, e s p e c i a l l y the lower bench. This i s the key bighorn sheep w i n t e r range of the Ashnola area, supporting 110 t o 160 sheep from October through June. The a r e a p i c t u r e d r i s e s from U000 t o 6,200 f t . i n e l e v a t i o n .  FIGURE 9. O u l l e y e r o s i o n o n South S l o p e , August I960. D e s p i t e climax p l a n t cover t h i s 18 i n c h deep g u l l e y r e s u l t e d from a s i n g l e c l o u d b u r s t .  FIGURE 1 0 . Sheet e r o s i o n o n South S l o p e , August i 9 6 0 . T h i s a r e a o f 30 t o hO degree s l o p e had much top s o i l removed b y a s i n g l e r a i n s t o r m . Dominant v e g e t a t i o n i s b l u e b u n c h wheatgrass, b u t t h e bunches a r e s m a l l , pedest a l e d and n o t growing v i g o r o u s l y .  11 bluffs rising combination  2000  f e e t from Ewart Creek a t t h e west end o f t h e s l o p e *  o f warm w i n t e r temperatures  A  a t t r i b u t a b l e t o t h e s o u t h e r l y ex-  posure,  and s t r o n g winds keeps most o f the s l o p e f r e e o f snow d u r i n g normal  winters  ( F i g u r e 11)«  The l a r g e expanse o f bunchgrass s l o p e , i n t e r s p e r s e d  w i t h broken b l u f f s and timbered a r e a s , p r o v i d e an e x c e l l e n t combination bighorn requirements.  of  T h i s i s expressed i n t h e l a r g e number o f sheep  w i n t e r i n g on t h i s range« B o t a n i c a l c o m p o s i t i o n o f the b i g h o r n ranges was l i n e - p o i n t sampling method as d e s c r i b e d by Dasmann were l o c a t e d on temporary 500 foot s t e e l tape.  The tape was  determined  (1951)•  by the  The p o i n t s  foot straight l i n e transects using a  fifty  s t r e t c h e d out on top o f the v e g e t a t i o n and  t h e dominant s p e c i e s o f cover t h a t o c c u r e d e i t h e r d i r e c t l y u n d e r o r d i r e c t l y o v e r each o f t h e f o o t marks on t h e tape was ten  times t o complete t h e  and f a i r l y  500$  points.  rapid i n application.  Brown  p o i n t s t o a d e q u a t e l y sample average  recorded.  The tape was  The method i s s i m p l e i n p r i n c i p l e  (1954:73)  pastures.  recommends  200  S i n c e the average  t o i|00 ground  cover c o n t r i b u t e d by v e g e t a t i o n on A s h n o l a w i n t e r ranges i s about 50 cent, t r a n s e c t s o f 500  moved  p o i n t s were c o n s i d e r e d t o be  per-  adequate, e s p e c i a l l y  s i n c e o n l y the dominant s p e c i e s a r e i m p o r t a n t i n range c o m p e t i t i o n s t u d i e s . S i n c e i n t h e l i n e - p o i n t method the f r e q u e n c y o f cover i s r e c o r d e d , i n t r a n s p o s i n g t h e d a t a t o percentage of  ground cover I have assumed t h a t f r e q u e n c y  cover i s d i r e c t l y p r o p o r t i o n a l t o percentage  face.  E i g h t , 500  coverage  p o i n t t r a n s e c t s were p l a c e d on r e p r e s e n t a t i v e p a r t s o f South  S l o p e and the d a t a a r e p r e s e n t e d i n Appendix T a b l e 2. (dead o r g a n i c m a t e r i a l ) were a l s o r e c o r d e d .  S o i l , r o c k , and  litter  " H i t s " were r e c o r d e d when the  p o i n t f e l l d i r e c t l y under o r over any p a r t o f a p l a n t . is  o f the ground s u r -  Species  composition  expressed as p e r c e n t o f t o t a l v e g e t a t i o n , r a t h e r than p e r c e n t ground  12 cover. I t can be seen from Appendix Table 2 that the areas sampled on South Slope d i f f e r e d appreciably i n f l o r i s t i c  composition.  These differences are  due p r i m a r i l y to a l t i t u d e , s o i l development and grazing history, the l a t t e r being the most important f a c t o r . plant species on t h i s range.  Bluebunch wheatgrass i s the dominant  Although c l o s e l y followed by Junegrass on a  percentage occurrence basis, the bunchgrass contributes much more forage on a weight or volume basis due to i t s densely bunching habit and t a l l upr i g h t leafage.  Richardsons needlegrass (Stipa Richardsoni) and intermediate  oatgrass, although present near the top of South Slope, were not recorded i n the transects.. The p r i n c i p a l changes from the primitive condition due to heavy grazing has been i n r e l a t i v e species composition of grasses.  Figure 13 shows that  bluebunch wheatgrass i s poorly represented on parts of South Slope that have a long h i s t o r y of heavy use.  Conversely, other grass species have  increased i n abundance, notably Columbia needlegrass on the South Slope bench, and bluegrasses at higher elevations. There has been no great change i n the t o t a l percentage of grasses present.  This shows that succession on  heavily used areas has not yet progressed to the annual weed stage.  A l l of  the transects i n Figure 13 were located on r e l a t i v e l y steep slopes.  On the  South Slope bench however, where past grazing has also been heavy, an excell e n t interspersion of grasses can be found along with much l i t t e r and l i t t l e exposed mineral s o i l .  This i s l a r g e l y due to a w e l l developed mantle o f  a l l u v i a l s o i l which has allowed some sod formation.  Also, since the area  i s not steep there has been no terracing or erosion, and the rate of water run-off i s not so great. for  Areas such as t h i s afford the best summer grazing  c a t t l e , but unfortunately are very l i m i t e d i n extent.  13  No appreciable difference i n production o f forbs on d i f f e r e n t parts of South Slope i s apparent.  The most abundant forb, yarrow (Achillea m i l -  lefolium) , i s widely d i s t r i b u t e d at high and low elevations and on heavily and l i g h t l y grazed s i t e s .  Chamaephytes, c h i e f l y pasture sage (Artemisia  f r i g i d a ) and eriogonum (Eriogonum heracloides) were found to be more abundant on heavy-use areas (Figure 13),  but widely d i s t r i b u t e d with respect  to elevation. The amount o f l i t t e r or mulch on the ground i s one o f the most r e l i able i n d i c a t o r s of range condition (Dyksterhuis 19k9)»  On South Slope,  areas of heavy past u t i l i s a t i o n have much l e s s l i t t e r than l i g h t l y grazed areas.  The amount of l i t t e r however, also varies somewhat with s o i l type,  drainage, slope, and botanical composition.  Coincident with  decreased  l i t t e r on heavy-use areas i s an increase i n exposed mineral s o i l . areas also are the most s e r i o u s l y eroded.  Such  On some of the steep lower slopes  where bunchgrass i s dominant and past u t i l i z a t i o n has been s l i g h t there i s also a large amount of exposed s o i l . The areas compared i n Figure 13 exposure.  This i s mostly a r e s u l t of a r i d i t y .  are quite s i m i l a r i n a l t i t u d e , slope and  Since only small areas of the South Slope Range have reverted  from the climax bunchgrass cover, i t s general condition may be c l a s s i f i e d as good. Juniper Slope The Juniper Slope range (Figure 7) Slope range, and between  i s located adjacent to the South  5000 and 6000 f e e t i n elevation. I t i s about 150  acres i n s i z e , has an average slope of about 10 degrees and a south-west exposure.  Due to the moderate slope no terracing i s evident, and erosion  has been s l i g h t .  Below the lower end of the slope the same b l u f f s which  border the west end of South Slope provide excellent escape t e r r a i n .  The  slope i s bordered on the north by mature Douglas f i r and Englemann spruce, and on the south by a burnt over area repopulated with young jackpine and spruce. water.  A small stream at the south side o f the slope provides year-round Much o f the slope i s blown free o f snow even i n February  (Figure 12).  Although located near South Slope, Juniper Slope d i f f e r s greatly i n plant cover.  Almost none o f the primitive bunchgrass remains, the dominant  species being Sandburg bluegrass and pasture sage (transects 9 and 10, Appendix Table 3).  The slope has obviously been exposed to heavy gracing  pressure f o r many years i n the past. and dominated by pasture sage.  The exposed knolls are very g r a v e l l y  The swales support mostly bluegrasses,  along with annual weeds such as mullein (Verbascum thapsus) and dandelion (Taraxacum o f f i c i o n a l e ) .  S o i l s i n these low spots have been g r e a t l y d i s -  turbed by pocket gophers (Thomomys talpoides) and elsewhere burrows o f the y e l l o w - b e l l i e d marmot (Marmota f l a v i v e n t r i s ) and Columbia ground s q u i r r e l ( C i t e l l u s columbianus) are common.  There i s no shrub growth on the slope  i t s e l f , but at i t s lower edge squaw current and s o o p o l l a l l i e are abundant. L i t t e r and mulch are almost nonexistent.  In general condition, t h i s slope  can only be c l a s s i f i e d as poor. Sheep move on to Juniper Slope frequently from South Slope, but do not stay on the former continuously through the winter as i n the l a t t e r case. Starvation-Flatiron These two slopes are p h y s i c a l l y quite s i m i l a r , and are located east of the Ashnola River and north o f Juniper Slope.  1*000  and  4,800  Both slopes are between  feet i n elevation and have a south-west exposure (Figure i i i ) .  Starvation averages 15 degrees i n slope, F l a t i r o n about 5 degrees. combined area i s about 250 acres.  Their  Neither slope i s terraced nor seriously  FIGURE 11. South Slope, February I960. The steepest part o f the slope i s free o f snow due to melting, sublimation and removal by strong winds.  FIGURE 1 2 . Juniper Slope, February i 9 6 0 . The ridge i n the background reaches 6,800 f t . i n elevation, y e t much of the area i s free o f snow. Many deer remain at t h i s elevation throughout the winter.  TRANSECT I (HEAVY USE)  TRANSECT 2 (MODERATE USE)  TRANSECT 7 (LIGHT U S E )  41 BLUEBUNCH (% OF T O T A L  2 8  WHEATGRASS  PLANT  COVER) 4 i  i 43  ALL (%  OTHER OF TOTAL  3 7  GRASSES PLANT  2 6  COVER)  29 C HAMAE PHYTES (%  OF  TOTAL  1 9  L I T T E R (%  G ROUND  1 1  PLANT COVER)  20  1 2 C OVE R )  1 45  EXPOSED (%  OF  AREA  FIGURE  13.  WHICH  36  SOIL SAM PLE D )  COMPARISON VARY  OF  ACCORDING  SOME TO  COVER GRAZING  CLASSES  ON  HISTORY.  SOUTH  SLOPE  15 eroded, but l i t t e r i s almost nonexistent.  These slopes, although bordered  by steep timbered areas, lack the neighbouring escape t e r r a i n that charact e r i z e s South Slope.  Snow depths are also greater because of less favorable  exposure and b e t t e r protection from the wind. Transect number 11  (Appendix Table 3) from Starvation Flats i s repre-  sentative of F l a t i r o n a l s o .  The data indicate that the area i s b o t a n i c a l l y  f a r removed from the climax condition. Bunchgrass i s almost nonexistent, while needlegrass, cheatgrass and bluegrasses are invading.  Annual weeds  such as dandelion and plantago (Plantago patagonica) are frequent i n occurrence. ure  A few shrubs such as rabbitbrush and rose occur on t h i s range (Fig-  15>). Forage production i s low and the range condition i n general i s poor.  According to P. ¥. Martin (i960) who  1951 and  I960,  surveyed the Ashnola sheep ranges i n  Starvation Flats and F l a t i r o n showed no improvement i n i960  over t h e i r condition i n  1951.  R e l i c t Slope This small area i s not important as sheep range, however i t i s not known to have been grazed by domestic stock and i s therefore u s e f u l as an i n d i c a t i o n of the climax condition. This slope i s between U,500 and 5,500 f e e t i n elevation, has a southerly exposure, and a slope of about 35  degrees.  I t i s p h y s i c a l l y therefore, very s i m i l a r to middle elevations o f South Slope. Transect number 12  (Appendix Table 3) i s from the R e l i c t Slope.  Here  the climax wheatgrass i s w e l l represented and invading grasses do not occur. Forbs are not abundant, nor are chamaephytes.  L i t t e r i s not w e l l developed,  but t h i s seems c h a r a c t e r i s t i c of steep bunchgrass slopes. terracing are not evident.  Erosion and  Many of these factors contrast strongly with  conditions on Starvation F l a t s , Juniper Slope, and parts o f South Slope.  FIGURE l4« S t a r v a t i o n F l a t s w i t h C r a t e r Mountain i n t h e background. T h i s range r e c e i v e s heavy s p r i n g d e e r use and s p r i n g and f a l l c a t t l e u s e . Use by b i g h o r n sheep i s light.  FIGURE 15• Gloseup o f S t a r v a t i o n F l a t s r a n g e . Commonest p l a n t s are r a b b i t b u s h , b l u e g r a s s , n e e d l e g r a s s , c h e a t g r a s s and d a n d e l i o n . None o f t h e o r i g i n a l c l i m a x b l u e b u n c h wheatgrass r e m a i n s . The range i s o v e r g r a z e d by c a t t l e and i n poor c o n d i t i o n .  16 C r a t e r Mountain The  C r a t e r Mountain w i n t e r - s p r i n g sheep range c o n s i s t s o f many  g r a s s l a n d s l o p e s on the s o u t h and s o u t h - e a s t o f the A s h n o l a R i v e r level to  2,500  (about  3000  (Figure 7).  f e e t ) up t o  s i d e s o f C r a t e r Mountain, e a s t  These s l o p e s are s c a t t e r e d from r i v e r  5,800  feet i n elevation.  2000  A total of  a c r e s o f open g r a s s l a n d are a v a i l a b l e f o r w i n t e r - s p r i n g use,  l a r g e s t s i n g l e slope being  about 600  acres i n s i z e .  s o u t h o r s o u t h e a s t e r l y exposure, and in  separate  slope.  The  winter-use  are m o s t l y 2$  s l o p e s are the s t e e p e s t  the  These areas have a degrees to 30  ( F i g u r e 16)  degrees  and o f t e n a t  h i g h e r e l e v a t i o n s t h a n s p r i n g - u s e range, much o f which i s r e l a t i v e l y (Figure  flat  17).  S e v e r a l streams a d j a c e n t t o t h e s e ranges p r o v i d e y e a r - r o u n d water. The most s u i t a b l e w i n t e r i n g s l o p e s a r e , i n normal y e a r s , f r e e o f snow f o r most o f t h e w i n t e r . escape t e r r a i n and very l i t t l e is  These l a t t e r s l o p e s however have l i t t l e a v a i l a b l e are m o s t l y b o r d e r e d  by mature Douglas f i r s .  shrub growth e i t h e r on o r a d j a c e n t to these r a n g e s .  There i s Terracing  prominent on t h e s t e e p e r s l o p e s , b u t e r o s i o n i s n o t as e v i d e n t as  on  ranges e a s t o f t h e A s h n o l a R i v e r . These ranges v a r y g r e a t l y i n b o t a n i c a l c o m p o s i t i o n . and 15 resents  (Appendix Table 3)  are from C r a t e r Mountain r a n g e s .  Number 13  a s p r i n g sheep-use a r e a o f heavy g r a z i n g h i s t o r y , number lh  w i n t e r sheep-use a r e a o f moderate g r a z i n g h i s t o r y , and number 1$ sheep-use a r e a o f l i g h t g r a z i n g h i s t o r y . l i t t l e bunchgrass, fewer t o t a l g r a s s e s , areas. root  Needlegrass i s a l s o i n v a d i n g .  (Balsamorhiza  The  rep-  a  a winter  h e a v i l y g r a z e d range  has  and more f o r b s than the o t h e r The  14,  T r a n s e c t s 13,  two  f o r b s here are c h i e f l y balsam-  s a g i t t a t a ) , a s p e c i e s n o t p r e s e n t on sheep ranges e a s t  o f the A s h n o l a R i v e r .  The  steeper winter-use  bunchgrass s l o p e s however  FIGURE 16. Typical winter bighorn sheep range on Crater Mountain at the 5000 f t . elevation. The bluebunch wheatgrass climax i s w e l l developed. Junegrass and Idaho fescue are also common. This range i s l a r g e l y free o f snow throughout the winter, but u t i l i z a t i o n i s l i g h t . No use by c a t t l e was observed here.  FIGURE 1 7 . Bighorn sheep spring range on Crater Mountain at the 1*000 f t . l e v e l . The large forb i s arrowleaf b a l samroot and the dominant grasses are junegrass and bluegrasses. Spring c a t t l e use i s also heavy here. Douglas f i r margin at r i g h t marks edge o f precipitous escape t e r r a i n shown i n Figure 3 9 .  17 have more exposed mineral s o i l than f l a t t e r areas that have reverted from the  climax condition.. L i t t e r i s nowhere abundant* These ranges can generally be c l a s s i f i e d as i n f a i r to good condition.  Forage production i s generally high. Lower Ashnola River Several small open slopes facing the Ashnola River from the mouth o f Gilanders Creek to the Similkameen Valley are used as winter ranges by ram groups, c h i e f l y from December to A p r i l .  Most o f the open areas have a  southeast or southwest exposure and are l a r g e l y snow-free throughout the winter.  The lower slopes are mostly i n poor condition with a cover o f  sagebrush and cheatgrass. Higher areas have the f a m i l i a r wheatgrass climax. Winter-spring deer use i s heavy.  Cattle u t i l i z e these slopes only when  f i r s t put on the range i n l a t e A p r i l or early  May.  Paul Creek The Paul Creek range, although at l e a s t 1000 acres i n extent, i s used by very few sheep.  Most o f the area i s 2$ degrees to 30 degrees i n slope,  and varies i n botanical composition c h i e f l y with a l t i t u d e . reaches from  2000  to over  5000  This range  feet i n elevation and varies from a sparse  cheatgrass-sagebrush association, to a dense bunchgrass-fescue-balsamroot association.  The range i s i n f a i r to good condition.  Only a small part  of i t i s used by sheep, c h i e f l y as a ram wintering area.  Cattle graze the  area through the summer, moving upward as forage develops. accessible by logging road. previously discussed.  This range i s  Fewer deer use t h i s range than the ranges  Factors u s e f u l i n comparing the condition o f the  important winter ranges are summarized i n Figure 18.  TRANSECT 12  NUMBER  I TO 8  RELICT  SOUTH  SLOPE  SLOPE  AND  9 AND 10 JUNIPER  LOCATION 13 11  STARVATION  SLOPE  SLOPE  CRATER  '  '  CRATER  (SPRING SHEEP  59  14 AND 15 (WINTER USE) S H E E P  USE)  '  BLUEBUNCH WHEATGRASS (%OF  TOTAL PLANT COVER  )  61  A L L OTHER (%0F  GRASSES  TOTAL  28  PLANT COVER)  1  8  4I  32.5  FORBS (%0F  TOTAL  26  19  PLANT  39  40  38.5  COVER)  19  3  I  3 3  CHAMAEPHYTES (%OF  TOTAL PLANT  16. 5  C O V E R  SHRUBS (%  OF TOTAL  PLANT  C O V E R )  LITTER (%  GROUND  )  1  9  6  6  1  4  1 0  0  11  11  0  5  f  1 3  0  1  3  1  1 1  C O V E R )  1  — J  6  43 EXPOSED  32  SOIL  ( % O F AREA SAMPLED )  F I G U R E 18. FACTORS  A ON  30  22 >2  COMPARISON IMPORTANT IN  THE  10  OF  SOME  RANGE  BIG HORN S H E E P ASHNOLA  CONDITION  AND T R E N D  W IN TE R - SPRI NG  REGION.  RANGES  1  18  HISTORICAL ACCOUNT Origin o f the Population Native sheep i n North America are derived from A s i a t i c stock which crossed the Bering land bridge during Pleistocene times*. Two d i s t i n c t species have developed from the o r i g i n a l stock. Ovis d a l l i , the thinhorn sheep with three races. i n central Alaska.  One o f them evolved as I t s centre o f o r i g i n l i e s  The second species developed south o f the great C o r d i l -  l e r a n i c e sheet l y i n g approximately between 6 2 degrees and US degrees north latitude.  This species s p e c i a l i z e d as Ovis canadensis, the bighorn sheep  with f i v e races.(Cowan 1°1;0). The C a l i f o r n i a bighorn, 0 . c. c a l i f o m i a n a , probably p e r s i s t e d from the S i e r r a Nevada Mountains o f C a l i f o r n i a north through the Cascade Mountains o f eastern Oregon into the southern Cascades and Columbia Plateau o f Washington during the l a s t , or Wisconsin, g l a c i a t i o n .  A f t e r the retreat  of the i c e about 1 0 , 0 0 0 years ago these sheep moved northward on to the east slope o f the Coast Mountains o f B r i t i s h Columbia, and on the I n t e r i o r Plateau.. Sugden (l?6l) discusses the whole matter o f history and recent status o f the C a l i f o r n i a bighorn i n B r i t i s h Columbia.  The Similkameen  region however, i s not treated i n d e t a i l . o Similkameen Herds Interpretation o f past events can t e l l us much about present status of bighorn sheep populations, and act as a guide i n future management. C a l i f o r n i a bighorn sheep populations i n B r i t i s h Columbia have a history p a r a l l e l i n g that o f bighorn sheep elsewhere i n North America -s? reduction i n both d i s t r i b u t i o n and numbers. Before white men frequented the Similkameen Valley, Indians o f the region exploited the sheep herds.  These people who had no salmon i n t h e i r  19 country depended l a r g e l y on hunting f o r food, through the Similkameen i n 1904,  Teit  (1927),  who  travelled  states that bighorn sheep were one of the  chief large game species hunted by Indians before the ooming of white  men.  In those days the Similkameen Indians had an annual l a t e winter hunt f o r sheep during which mostly ewes were k i l l e d and the rams were l e t go..  The  l a t t e r were hunted by small p a r t i e s i n the l a t e summer and early f a l l .  At  t h i s time the rams are f a t and i n t h e i r best condition. T e i t also relates a story o f a famous winter sheep hunt i n the Ashnola which took place early i n the past century.  Sheep at t h i s time were abundant and the Ashnola  Indian band decided to host a great winter hunt.  Indians came from other  Similkameen bands and from the Thompson and Nicola Rivers, Okanagan Lake, Columbia River, and Shushwap regions.  The hunt was i n the form o f a drive,  and from the description o f the t e r r a i n l i k e l y took place on Crater Mountain.  Many sheep were secured. Present day residents o f the Similkameen V a l l e y also t e l l of drive-  hunts on Crater Mountain r e l a t e d to them by since deceased n a t i v e s .  As  early reports of white t r a v e l l e r s i n the area indicate sheep were abundant i n the l a t e  l800's (Grinnell 1928, Phillipps-Wooley 1888), exploitation by  Indians must not have seriously decimated the herds. The f i r s t s e t t l e r s arrived i n the Similkameen i n 1859 gold rush took place. 1955)  when a minor  By 1861 a wagon road passed through the area (Flucke  increasing access to sheep herds. G r i n n e l l (op. c i t . ) hunted i n the mountains o f the Similkameen i n  1887  and saw bighorn sheep onstantly i n the high grassy v a l l e y s , probably i n the Ashnola region.  He considered that up to t h i s time the sheep here had not  been greatly disturbed. That hunting pressure i n the area sharply increased at t h i s time however i s indicated by Phillipps-Woolley (op. c i t . ) who hunted  20 Crater Mountain and v i c i n i t y , also i n 1 8 8 7 .  He states:  "I had come about 6 , 0 0 0 miles to t r y a country (Ashnola) o f which I had heard four years ago, and on a r r i v a l was t o l d that there were two p a r t i e s o f Americans already ' i n ' , that others had preceded them and come out, that at l e a s t one party o f Englishmen were making t h e i r way to my happy huntinggrounds from a point further east, and the greater part o f the o f f i c e r s o f H. M. 's Wavy intended to follow s h o r t l y . " No sex, age, or bag r e s t r i c t i o n s existed at t h i s time. Woolley and a companion shot 3 ewes and 3 rams. sheep were quite unwary.  In one day P h i l l i p p s -  Evidently at t h i s time the  Several wolves, a wolverine and a lynx were seen  during t h i s expedition, but there i s no mention o f cougars. In I 8 8 9 Professor L. L. Dyche made an expedition to Mount Chopaka, which l i e s immediately adjacent the B r i t i s h Columbia boundary i n Okanagan county, Washington (Dalquest and Hoffmeister, 1 9 4 8 ) .  On t h i s expedition  Dyche collected 5k specimens o f C a l i f o r n i a bighorn sheep.  Some o f these  undoubtedly came from the Ashnola herd, since Dyche t r a v e l l e d f o r two days north o f Mount Chopaka on one occasion-(Edwords, 1 8 9 3 ) . also came upon two market hunters i n t h i s region.  Dyche and party  Dyche states;  the  p i l e s o f deer and sheep skins which l a y about the camp made i t evident that they were skin-hunters, ...". Dyche found only rams on Mount Chopaka, and t r a v e l l e d north and west to get ewes and lambs.  His descriptions o f sheep  stalking i n f e r that the sheep were every b i t as wary as they are today. Buechner ( i 9 6 0 ) quoting from Hornaday ( 1 9 0 1 ) says that Dyche saw 5>00 head o f sheep i n Washington and B r i t i s h Columbia on t h i s expedition.  Bears,  wolverines and lynx were common at t h i s time. Williams  ( 1 9 2 5 ) states that when he f i r s t came to the Ashnola the  region was "... simply a l i v e with sheep, and had been f o r so many years that they were forced to migrate."  Williams blames excessive hunting on  21 the great decline i n Similkameen sheep herds which took place i n the l a t e l800's, and o f the Ashnola herd says, "The sheep were p l e n t i f u l and so confiding that the v e r i e s t duffer could k i l l them, and so a l l sorts and conditions o f men flocked there intent on slaughter." The Okanagan-Similkameen bighorn herds were closed to hunting i n 1909, and a Game Warden was sent into the Ashnola "especially to look a f t e r the sheep" ( B r i t i s h Columbia  1910).  Ashnola i n the f a l l o f 19l4,  Over  100  head were seen together i n the  however i n 1926 i t was reported that the  Ashnola herd had shown no increase during the past eighteen years o f closed season ( B r i t i s h Columbia  1914  and 1926).  In  1928  a provincial police  constable counted " i n the neighbourhood o f 100 sheep i n the Ashnola area." Natural predators and Indians were suggested as decimating the herds at t h i s time. Also i n 1928, Mr. Hamilton M. Laing"^" made an expedition into the South Slope area to c o l l e c t bighorn sheep f o r the National Museum o f Canada. Although there had been a closed season on the Ashnola herd f o r 19 years, Mr. Laing reports that he found "uncounted numbers" o f recently deposited r i f l e cases at strategic locations on South Slope.  Coyotes were also  numerous a t t h i s time. Game Department reports f o r 1933 to 1941 a l l report no change or no increase f o r the Ashnola herd, however i n 194-2 a "substantial" increase was reported.  In 1946 a t o t a l o f 500 sheep were estimated by game warden  Monks i n the Vaseaux Lake and Ashnola bighorn herds.  Subsequent counts  suggest that t h i s estimate was i n excess o f actual sheep numbers.  Five  hundred head was thought to be beyond the carrying capacity o f the range, therefore a short open season was allowed i n the Ashnola i n 1947. hunting was allowed from ^ L e t t e r received July 24,  1948  until  1961.  1955*  No  22 Frequent surveys of the Okanagan-Similkameen bighorn herds were made by Dr. Ian M T. Cowan of the University o f B r i t i s h Columbia from May u n t i l June 1955.  1950  A e r i a l censuses o f the Ashnola herd have been made each  2 winter from 1955  u n t i l the present.  Ground counts (horseback) by members  o f the Keremeos-Cawston rod and gun club i n company with B r i t i s h Columbia Game Branch personnel were made i n the spring of 1957  and 1958.  Data from  the above sources dLr-e presented i n Table 2. Although figures i n Table 2 vary from 8 l to 193, techniques are quite constant.  results of individual  The a e r i a l counts agree well with counts  made by Dr. Cowan, and are similar to numbers a lone person could expect to see at present on a one day t r i p over the same route.  The  horseback  counts however r e f l e c t the greater e f f i c i e n c y of more observers i n the area f o r a longer period of time, and more c l o s e l y represent true population s i z e . No duplications are thought to e x i s t .  The figures suggest l i t t l e change i n  numbers since the early 1900's. According to l o c a l residents, bighorn sheep once inhabited the S i m i l kameen Valley proper. wintering area.  Because of the low elevation t h i s was presumably a  The f a c t that Indians, before a r r i v a l of the white  man,  went back into the mountains to hunt sheep i n l a t e winter i s not compatible with the above observation however.  I t seems more l i k e l y that large v a l l e y s  such as the Similkameen served as emergency winter ranges during p a r t i c u l a r l y severe winters, as suggested by Edwards (1956).  Fencing, c u l t i v a t i o n , and  over-grazing have crowded the C a l i f o r n i a bighorn sheep from these occasiona l l y e s s e n t i a l ranges.  Thus ranges such as South Slope and Crater Mountain,  which are adequate during average winters, must now carry the population through severe winters a l s o . p  The r e s u l t can only be a reduction i n herd  Data from Taylor, E. ¥., Unpublished report.  23  TABLE 2 RECENT CENSUS FIGURES FOR THE ASHNOLA BIGHORN SHEEP HERD  Date May 1950 Dec. 1950 Dec. 1951 Dec. 1952 April 195U June 1955 Feb. 1955 April 1956 Jan. 1957 May 1957 March 1958 April 1958 Jan. 1959 Jan. I960 March i 9 6 0  Sheep Counted South Slope A l l Ashnola Only 99  102  91  102  117  131  116  130 9k  193  109 180  95 81  122  1  Technique On foot (Dr. Cowan) idem idem idem idem idem Aircraft idem idem Horseback, 1 3 men, 3. days Aircraft Horseback, 6 men, 3 days Aircraft idem idem  'Always includes South Slope and Crater Mountain, but not always lower Ashnola River and Paul Creek.  24 numbers• The Ashnola bighorn population then, seems to have fluctuated l i t t l e i n s i z e since protection began i n 1909, but had experienced a considerable decline previous to t h i s date, probably due to excessive hunting and l o s s of emergency winter ranges.  Natural predation and Indian hunting are not  thought to have contributed s i g n i f i c a n t l y to the early decline, since the herds must have existed compatably with such influences f o r many years previously. North and east o f the Similkameen River bighorn sheep formerly ranged from the i n t e r n a t i o n a l boundary to Princeton.  These populations also de-  c l i n e d greatly l a t e i n the l a s t century, but f a i l e d to regain numbers and disappeared completely by about 1923.  Excessive hunting by miners i n the  Nickle Plate region i s thought to have been a contributing, factor (personal communication with l o c a l r e s i d e n t s ) .  Range Use The Ashnola area as a whole has been i n use by c a t t l e and horses f o r 80 to 90 years.  In 1 8 8 2 there were already kO farmers and 33 stockmen i n  the Okanagan and Similkameen Valleys (Vrooman, 1 9 4 l ) .  For two years i n  the early 1 9 2 0 ' s domestic sheep were pastured i n the South Slope area, but they used alpine ranges i n the area u n t i l the 19U0's.  As early as 1 9 1 2  Game Department reports suggest c o n f l i c t f o r range, stating that the b i g horn sheep winter ranges were being "fed o f f i n summer by domestic sheep." Hamilton Laing (op. c i t . ) found the South Slope ranges i n 1 9 2 8 "eaten bare" by UOO head o f c a t t l e . over-stocked.  I f t h i s number i s correct, the range was c e r t a i n l y  Competition f o r these ranges then, i s not a recent develop-  ment. The Crater Mountain, S t a r v a t i o n r F l a t i r o n , South Slope-Juniper and  25 Joe Lake ranges presently a l l f a l l within the grazing permit o f Mr.  H.  Tweddle, Gawston B. G.  Accurate data on stocking o f these ranges i s  lacking p r i o r to 1951.  Only since 1951  have separate grazing permits been  issued f o r Crater Mountain and ranges east o f the Ashnola River.  It i s  estimated however, that t o t a l stocking f o r these ranges before 1951 about ij.00 head o f c a t t l e (Martin, i 9 6 0 ) . head.  In 1952 t o t a l stocking was  was . 150  This was increased as Mr. Tweddle r e b u i l t his herd u n t i l the range  was stocked to estimated capacity i n 1955 when the Crater Mountain area c a r r i e d 175 head o f c a t t l e and 10 horses and the South Slope-Joe Lake ranges carried 125 head of c a t t l e .  In 1957  estimates of carrying capacity were  revised upward and the South Slope-Joe Lake ranges carried 150 head of c a t t l e and Crater Mountain was stocked with 190 c a t t l e and 10 horses.  Present  stocking i s the same except the 10 horses have been removed. Reports of Ashnola range condition have varied considerably during the l a s t decade, depending upon c a t t l e management and resulting forage carry over on important bighorn sheep wintering ranges.  Reports of over-  grazing however, have been predominant. PRESENT DISTRIBUTION AND NUMBERS D i s t r i b u t i o n of the C a l i f o r n i a bighorn sheep by winter and summer ranges i s outlined i n Figure 1 9 .  The winter range i s thought to be about  the maximum area occupied from November to June.  Long time residents o f  the area have occasionally seen sheep outside o f the area marked as summer range.  Considerable t r a v e l l i n g i n the area however, revealed the region  outlined i n Figure 19 to contain the majority of the summer range.-  Figure  7 outlines the winter range u n i t s i n d e t a i l . Counts have been made on both winter and summer ranges to determine absolute population size of the Ashnola herd.  Whenever sheep groups were  FIGURE 19 ( o p p o s i t e ) . i n the Ashnola region.  Map showing  c a t t l e and b i g h o r n sheep  distribution  The w i n t e r sheep range shown i s t h e maximum a r e a  u s e d from November t h r o u g h May.  Summer range areas shown a r e r e g i o n s o f  i n t e n s i v e summer use b y sheep b u t a r e n o t t h e maximum summer range.  UNITED  STATES  26 encountered  t h e y were counted,  b u t because o f r e p e t i t i o n t h e s e f i g u r e s  c o u l d n o t always be used t o determine maximum p o p u l a t i o n s i z e *  A  series  o f u n d u p l i c a t e d b u t l a r g e l y u n c l a s s i f i e d counts d u r i n g t h e summer o f I960 show t h e p o p u l a t i o n t o c o n s i s t o f n o t l e s s than 2lj.2 a n i m a l s . l a r g e l y c o n s i s t s o f two  The p o p u l a t i o n  s e p a r a t e u n i t s , t h o s e sheep w i n t e r i n g e a s t o f the  A s h n o l a R i v e r , p r i m a r i l y on S o u t h S l o p e , and t h o s e w i n t e r i n g west o f the Ashnola  ( G r a t e r Mountain and P a u l C r e e k ) .  Approximately  170  sheep pass  t h e w i n t e r on t h e e a s t s i d e o f the A s h n o l a R i v e r and 70 on t h e west s i d e .  ANALYSIS OF THE  POPULATION  An animal p o p u l a t i o n i s a dynamic e n t i t y , i t s c o m p o s i t i o n b e i n g c o n t i n u a l l y a l t e r e d by b i r t h s , deaths to understand  and movements.  B e f o r e we  changes w i t h i n t h e A s h n o l a b i g h o r n sheep p o p u l a t i o n we  be  a b l e to measure a t l e a s t a few o f i t s f e a t u r e s .  to  l o g i c a l l y i n t e r p r e t these measurements.  must  Then i t i s n e c e s s a r y  This analysis should r e v e a l  v i t a l s t a t i s t i c s which c h a r a c t e r i z e the l i v i n g p o p u l a t i o n . o f t h e herd  can b e g i n  Frequent  census  ( r e l a t i n g t h e p o p u l a t i o n t o space) combined w i t h a d e t a i l e d  population analysis  ( r e l a t i n g t h e p o p u l a t i o n t o time) s h o u l d p r o v i d e a  b a s i s f o r f u t u r e management. Among t h e raw  d a t a r e q u i r e d f o r p o p u l a t i o n a n a l y s i s are numbers o f  i n d i v i d u a l s o f each sex and age c l a s s .  These v i t a l s t a t i s t i c s  are b e s t  t e r m i n e d from m o r t a l i t y d a t a , however an a b s o l u t e census o f the l i v i n g  depro-  v i d e s n e a r l y the same i n f o r m a t i o n except t h a t l o n g e v i t y cannot be measured.  Rate o f P o p u l a t i o n I n c r e a s e Accurate population s t a t i s t i c s  f o r the A s h n o l a b i g h o r n h e r d have been  g a t h e r e d o v e r a p e r i o d o f one y e a r o n l y . e q u a t i o n , Nj. - N e ^ w h i c h appears r  0  T h e r e f o r e t h e w e l l known growth  i n r e c e n t t e x t s on e c o l o g y (Odura,  1959:  27 1 7 8 , Andrewartha and Birch, 195U:35 to 36) cannot be applied to determine rate o f population increase*  Likewise, although lamb-to-ewe r a t i o s can be  determined when rate constants are known (Kelker, 19U7:l80j Buechner, I 9 6 0 : 8 6 ) i t i s not possible to reverse the procedure and calculate rate-constants from observed lamb-to-ewe r a t i o s * F i e l d lamb-to-ewe r a t i o s alone provide only a measure o f n a t a l i t y at the time o f year when the observations are made, and the rate o f population increase cannot be determined without mortality data.  I f the rate o f  mortality i s extremely low however, as i n a r a p i d l y increasing population, the rate o f increment can be judged from lamb-to-ewe r a t i o s .  This i s not  l i k e l y to apply to the Ashnola herd however, since the population has r e mained r e l a t i v e l y constant f o r several years. M o r t a l i t y data necessary to measure rate o f increase i n t h i s population have been obtained from two sources.  Mean annual mortality rate from age  structure data i s presented i n the next s e c t i o n .  Rate o f change between  lamb-to-ewe and yearling-to-ewe r a t i o s also provides a measure o f m o r t a l i t y . Such data however, indicate lamb mortality, but not y e a r l i n g mortality which i s s t i l l l i k e l y to be comparatively, high.  Thus i n a r e l a t i v e l y stable  herd such as that i n the Ashnola, yearling-to-ewe ratios seem to be the best approximation o f population increase. Without information on mortality however, even these may be misleading. Whenever possible, sheep groups encountered i n the f i e l d were c l a s s i f i e d to sex and age. The lamb and yearling r a t i o s have been obtained by comparing the lamb and y e a r l i n g counts with the ewe counts rather than with the combined counts o f ewes and rams.  Knowing the number o f rams, the  r a t i o can then be given i n terms o f the entire population i f desired. When only part o f a group was c l a s s i f i e d the record was not placed i n the  \  28 tabulations.  As ewes during lambing, and when the lambs are very young,  tend to be separated from the more e a s i l y observed larger bands, counts during t h i s period were not generally included. Misleading ewe-yearling r a t i o s could also arise during t h i s period, since while the majority of ewes are not r e a d i l y v i s i b l e , the yearlings remain on South Slope with those few ewes which are immature, barren, or which have had t h e i r lambs earlier.  The opportune time to obtain lamb and y e a r l i n g r a t i o s f o r t h i s  herd i s during June, before the sheep have begun t h e i r summer migrations and l a t e enough to include most of the lambs. An absolute population census by age and sex classes could not be made although t h i s was  approached f o r sheep east of the Ashnola River.  This i s  understandable since rams over f i v e years o f age and ewes over two years cannot be aged accurately i n the f i e l d , and lambs and yearlings cannot be sexed accurately. Ratios derived from population samples however are s u f f i c i e n t l y accurate e s p e c i a l l y when repeated and compared.  Such r a t i o s  w i l l also be d i r e c t l y comparable to r a t i o s obtained by future investigators of t h i s herd. In the following discussion of age r a t i o s i t has been assumed that y e a r l i n g ewes do not breed, that breeding ewes have only one lamb each year,. and that ewes do not l i v e beyond breeding age.  I t was not possible to  ascertain whether or not two-year-old ewes i n the Ashnola gave b i r t h to lambs.  However, Cowan  (1950-1955) found a well developed corpus luteum  i n a two year o l d ewe collected i n the Ashnola i n July 1951.  Presumably  yearling sheep can breed under conditions of superior n u t r i t i o n . The extent o f twinning i n the herd was  also d i f f i c u l t to determine.  On June 8, i 9 6 0 , Arthur Bailey recorded a group of nine ewes with ten lambs, and on December 30, I 9 6 0 and May 25,  1 9 6 l I observed groups of s i x  29  ewes with seven lambs and seven ewes with eight lambs r e s p e c t i v e l y .  The  December group was observed f o r one and one h a l f hours during which time no other ewes entered the group and no lambs l e f t .  Since sheep groups on  South Slope do frequently s p l i t and r e j o i n however, i t cannot be concluded that twins were indeed observed.  Buechner (op. c i t . ) has concluded after  an extensive l i t e r a t u r e review that bighorn sheep twinning i s so infrequent that i t i s not l i k e l y to influence the rate of population increase. Dr. I . M T. C  Cowan (personal communication) reports that o f s i x bighorn sheep b i r t h s  i n the animal u n i t at the University of B r i t i s h Columbia, two were twins. The high lamb-to-ewe r a t i o s f o r June I960 (Table 3) also suggest that twinning and/or breeding o f y e a r l i n g ewes may be occurring i n the Ashnola herd. The r a t i o data presented i n Tables 3, U, and $ indicate the manner i n which the population i s performing with regard to rate of increment.  Cal-  culated r a t i o s were obtained by adjusting the ewe groups to approximate the number of breeding ewes.  The adjustments  are necessary.to provide a  uniform basis f o r comparison because the observed ewe c l a s s i f i c a t i o n s cons i s t e d o f three d i f f e r e n t kinds of composition.  In Tables 3 and k only  two-year-old ewes were included with ewes bearing lambs.  In Table 5 two  kinds of p a r t i a l c l a s s i f i c a t i o n are present; i n one case yearlings o f both sexes and two-year-old i n d i v i d u a l s of both sexes were included i n the ewe class.  These d i f f e r e n t compositions o f the ewe catagory r e s u l t from d i f f e r -  ences i n opportunity to r e f i n e the c l a s s i f i c a t i o n o f the observed animals. Under close, favorable observation y e a r l i n g s could be distinguished i n the f i e l d but not necessarily with complete accuracy.  Two-year-old ewes could  not be distinguished r e a d i l y even at close range.  Two-year-old rams how-  ever ^_ often found i n the ewe-yearling-lamb horn s i z e *  groups _were obvious by t h e i r  30 TABLE 3 LAMB AND YEARLING--TO-EWE RATIOS FOR COMPLETELY CLASSIFIED SHEEP GROUPS EAST OF THE ASHNOLA RIVER  Location South Slope South Slope South Slope Cathedrals Cathedrals South Slope South Slope South Slope South Slope South Slope South Slope  Date Feb. 13 I960 June 13 and 17 June 8 to July July 15 to 30 Sept. 3 Oct. I 9 6 0 Nov. I 9 6 0 Dec. I 9 6 0  Jan. 1961 Feb. 1 9 6 1 June 1 9 6 1  Observed Lamb-toEwe Ratio  No. Classified 47 117^ u  3 1  )  21*3 303 19*  303 263 53 3  33:100 83:100 86:100 70:100 78:100 73:100 67.5:100 70:100 69:100 58:100 68:100  ;Mean o f two duplicated counts ;Mean o f seven unduplicated counts 'Mean o f three unduplicated counts ^Single count 'Mean o f eight unduplicated counts  Calculated Lamb-toEwe Ratio U3:100 108:100 112:100 91:100 101:100 95:100 88:100 91:100 90:100 75:100 88:100  Observed Yearlingto-Ewe Ratio  Calcu. Yearl.to^-Ewe Ratio  18.5:100 15.5:100 10:100 11:100  2U:100 20:100 13:100 lU:100  9:100 12:100 12:100 21:100 61:100  12:100 16:100 16:100 27:100 79:100  31 TABLE 4 LAMB-AND YEARLING-TO-EWE RATIOS FOR COMPLETELY CLASSIFIED SHEEP GROUPS WEST OF THE ASHNOLA RIVER  Location  Date  Crater Peak Lower Crater Lower Crater Lower Crater  Aug. Nov. Jan. June  7. i 9 6 0 14-15, I 9 6 0 16, 1961 9 , 1961  Single count.  No. Classified  Observed Lamb-toEwe Ratio  Calculated Lamb-toEwe Ratio  Observed Yearlingto Ewe Ratio  Calcu. Yearl.to-Ewe Ratio  46 16 22 31  1  27:100  27:100 15:100  35:100 35:100  15:100  1  18:100  19:100 23:100  19:100  39:100  51:100  54:100 33:100  70:100 43:100  1  Note some samples rather small.  TABLE 5 LAMB-TO-EWE RATIOS:  Location South Slope South Slope Crater Mtn. Cathedrals Crater Mtn. Cathedrals  Date June 15, I960 June 10-24, I960 July 8, i960 July 12, i960  Aug..7, I960 Sept.  1, i960  PARTIALLY CLASSIFIED COUNTS  CalcuNo. Observed l a t e d Observed Clas-Lamb-to Lamb-to-Lamb-tos i f - Ewe . Ewe Ewe ^ i e d Ratio^ Ratio Ratio  154^ 64:100 59:100 363 523 30 3  133:100 123:100 16:100 48:100 27:100 43:100  Calcu- SCalculated lated Lamb-to- Lamb-toEwe Ewe Ratio Ratio  38:100 114:100 64:100 102:100  Calculated using mean yearling-to-ewe r a t i o f o r June-Sept. ^Some duplications ^Mean of f i v e unduplicated counts I Single unduplicated count ^Yearling and two-year-old ewes included -'Yearlings and two-year-olds of both sexes included  74:100 69:100  i960.  (Table  3)  32 From the breeding p o t e n t i a l table o f Leopold  (1933:256) f o r species  bearing t h e i r f i r s t young at three years o f age i t can be calculated that 23 percent o f ewes w i l l be two-year-olds.  Thus the calculated r a t i o s i n  Tables 3 and k were determined by subtracting 23 percent o f the animals c l a s s i f i e d as ewes.  The calculated r a t i o s i n these tables are somewhat  high since Leopolds' table i s based on an unimpeded rate o f increase.  Like-  wise, where y e a r l i n g s o f both sexes and two-year-old ewes were included with breeding ewes (Table 5), 52 percent o f the animals c l a s s i f i e d as ewes. were subtracted, and where the y e a r l i n g and two-year-old i n d i v i d u a l s o f both sexes were included 58 percent were subtracted.  The calculated r a t i o s o f  Table 5 may be f a r too high, depending on the rate o f mortality o f young animals over the i n i t i a l two-year p e r i o d . The most s t r i k i n g feature evident i n the r a t i o s f o r sheep east o f the Ashnola River between June I960 and June 196l i s that lamb-to-ewe r a t i o s are high, while yearling-to-ewe r a t i o s are low. February  The low lamb-to-ewe r a t i o i n  i960 and the low yearling-to-ewe r a t i o s i n June i960 (lambs were  considered to become yearlings on May 1) i n d i c a t e that either the lamb crop was small i n the spring o f 1959, or that lamb s u r v i v a l was low during the winter o f 1959-60.  The l a t t e r seems more l i k e l y to be true.  The high lamb-  to-ewe r a t i o s i n Tables 1 and 3 indicate an excellent lamb crop i n the spring o f i960 with a steady but moderate lamb loss through the following winter and a r e s u l t i n g high yearling-to-ewe r a t i o f o r June 1961 (Table 3 ) . Observed r a t i o s from Table 3 are graphically presented i n Figure 20.. Such v a r i a b i l i t y i n lamb s u r v i v a l could r e s u l t from one o f several environmental factors, among them, amount o f snowfall, snow conditions, and winter temperatures.  The winter o f 1959-60 was o f average severity,  while that o f 1960-61 was much milder than average f o r t h i s region.  *3  J  !  ,  F E B MAR A P R FIGURE 2 0  MAY JUN J U L AUG S E P I960  EWE-LAMB  AND  EWE-YEARLING IN  \  OCT NOV DEC U A N I  THE  RATIOS  ASHNOLA  AS  I  BIGHON  FEB  M A R APR MAY J U N 1961  INDICATORS HERD.  OF  PRODUCTIVITY  33 West o f the Ashnola River (Crater Mountain and v i c i n i t y ) both lambto-ewe and yearling-to-ewe r a t i o s have been low throughout the study. Although the number o f animals c l a s s i f i e d was frequently small, the larger numbers (Table 4 , l i n e l ) represent most o f the population i n t h i s area and thus should be i n d i c a t i v e o f population status here. The r a t i o s show that at l e a s t i n some areas at some times mortality over the f i r s t year i s high.  Therefore calculated r a t i o s w i l l also be high,  e s p e c i a l l y those i n the p a r t i a l l y c l a s s i f i e d counts.  Thus the data i n Tables  3 and k are more t r u l y i n d i c a t i v e o f the population. In Table $ the actual r a t i o s should l i e somewhere between the observed and calculated values but closer to the observed value than i n Tables 3 and 4 .  The lamb-to-ewe r a t i o s  i n Table 5 calculated using the mean yearling-to-ewe r a t i o f o r June to September (Table 3) should be close to the actual ratios, since f i r s t year losses are taken into account.  The f a c t that some sheep groups seem to  have no yearlings and others many, that i s , that yearlings are not always found i n numbers proportional to the non-yearling component o f the group, w i l l also decrease the r e l i a b i l i t y o f r a t i o s derived from groups i n which yearlings cannot be segregated. The r a t i o data then, suggest that the population east o f the Ashnola River was r e l a t i v e l y stable before June 1961,  and i s i n i t i a l l y at l e a s t ,  increasing after that date, while west o f the Ashnola River the population i s decreasing. The net e f f e c t i s probably a r e l a t i v e l y stable population. Ram age c l a s s i f i c a t i o n and ram-to-ewe r a t i o s have also been determined. The ram c l a s s i f i c a t i o n was done on South Slope i n May, during July and August.  Rams two years o f age and older were c l a s s i f i e d  as follows: 2 year  10  3 year  16  and on summer range  4 year  13  $ year and over  32  34 Ram survivorship from two to five years i s relatively constant.  Since only  rams with three-quarter curl horns can be harvested and this size i s attained at about 5> years under normal conditions, a good proportion of harvestable animals s t i l l exists i n the population. In the ram-to-ewe ratios (Table 6) yearlings have been omitted from both catagories.  The ratios indicate that selective hunting for rams has  not been effective i n lowering ram numbers. The ratio for the combined areas should be the most significant, since the amount of ram movement between the two areas i s undetermined. These ratios are based on summer counts, and could vary somewhat since the sexes are largely separated at this time of the year and either sex could be underestimated.  The fact that most of  the Ashnola population i s included however, should reduce this error. On the other hand, ratios obtained on a specific part of the bighorn range, for example South Slope, and including only a sample of the population, are biased due to variations i n regional distribution of the sexes through the year.  The following ram-to-ewe ratios for South Slope i n the winter of 1960-  6 l indicate the variation found when the classification i s confined to a limited area. Oct.  Nov.  Dec.  Jan.  Feb.  78:100  100:100  70.5:100 39:100  32:100  Mar.  34:100  Such variations i n regional distribution of the sexes w i l l be further discussed under the heading of Migrations and Movements. A breeding season classification on Crater Mountain (November 14-15, I960), revealed a sex ratio of 27 rams to 100 ewes, (based on 19 animals),considerably lower than the summer ratio i n Table 6. This may indicate movement of rams from Crater Mountain to the East side of the Ashnola River before the breeding season.  35 TABLE 6 RAM-TO-EWE RATIOS, i960  Rams 2 y r s . and over  Location  71 22 93  East o f Ashnola West o f Ashnola Combined  Ewes  Ratio  54  131s100 78:100 113:100  28 82  Rams 5 y r s . and over  32 9 111  Ewes  Ratio  54  59:100 32:100 50:100  28  82  No optimum ram-ewe r a t i o has been ascertained, but considering the polygamous nature of bighorn sheep, the above proportion o f males should be more than adequate to insure breeding o f a l l receptive females on the range, e s p e c i a l l y on areas such as South Slope where there i s a large concentration o f sheep during the breeding season.  Because o f the i s o l a t i o n  and smallness o f other bands however, the r a t i o i n such areas should not be greatly lowered. The rate o f population increase i s also influenced m a t e r i a l l y by the sex r a t i o .  Kelker (1947) shows how to calculate ' r (rate o f increase) f o r 1  a population with an unbalanced sex r a t i o .  There i s a s i g n i f i c a n t increase  i n rate o f population growth r e s u l t i n g from lowering the male side o f the sex r a t i o .  This indicates that continued harvesting o f rams i n the Ashnola  herd could increase n a t a l i t y and i s a point i n favor o f maintaining the existing hunting season. Rate o f Population Replacement I f the Ashnola bighorn population i s neither increasing, nor decreasing, that i s , i s r e l a t i v e l y stable, the mortality rate w i l l be equal to the r e placement r a t e .  The m o r t a l i t y rate then, measures the flow o f i n d i v i d u a l s  36 through the population.  The mean annual mortality rate o f the population  can be calculated from a l i f e table constructed on the basis of the number o f deaths i n each o f the age groups. Throughout the study a l l s k u l l s , mandibles and horn sheaths o f dead bighorn sheep encountered i n the Ashnola region were c o l l e c t e d .  Although  t h i s amounted to only f i f t y seven specimens i t i s believed representative of the population since the area i s rather small and was searched i n t e n s i v e l y . F i f t y seven specimens o f known age are not s u f f i c i e n t to construct a r e l i able l i f e table, however since no l i f e table has been constructed f o r the bighorn sheep t h i s was attempted with the available material. Construction o f a l i f e table requires that the age of death of animals i n the population can be accurately determined.  This was  conveniently  accomplished by counting annual growth rings on sheep horns picked up i n the f i e l d .  Some inaccuracy i s introduced when the growth rings become  crowded i n the older aged animals, and i t i s p a r t i c u l a r l y d i f f i c u l t to count growth rings on horns o f ewes i n the older age groups. percentage o f cases no horn sheaths could be found.  In a small  In such cases animals  under four years o f age were aged by tooth eruption and replacement (Mosby, 1960:6: £8).  The few s k u l l s o f sheep over four years o f age which had no  horn sheaths were aged on the basis o f tooth wear and length of the horn core.  Despite these inaccuracies, a good approximation o f population  mortality can be made. The l i f e table i s constructed on the assumption that the s k u l l s picked up are a f a i r sample o f the t o t a l population, that i s , that the p r o b a b i l i t y of finding a s k u l l i s not l i k e l y to be affected by the age o f i t s owner. This assumption i s not l i k e l y sound since the lamb and y e a r l i n g classes w i l l undoubtedly be under-represented owing to the p e r i s h a b i l i t y o f t h e i r  (1)  37 skulls. ing  Hunting s e l e c t i o n f o r o l d rams w i l l a l s o have the e f f e c t o f remov-  animals from the p o p u l a t i o n w h i c h have s u r v i v e d the c r i t i c a l lamb-  y e a r l i n g s t a g e , and would o t h e r w i s e be found i n the 5 y e a r and o v e r A l s o , s e v e r a l l a r g e ram  group.  s k u l l s are known to have been removed from the area  by t o u r i s t s and o t h e r s f o r t h e i r s o u v e n i r v a l u e .  Animals which d i e a f t e r  b e i n g c r i p p l e d i n t h e h u n t i n g season, and poached animals, would also to  d i s t o r t t h e sample. A l i f e t a b l e f o r the 57  (Table 7). 21,  b i g h o r n sheep has a c c o r d i n g l y been p r e p a r e d  S u r v i v o r s h i p and m o r t a l i t y curves have been p l o t t e d i n F i g u r e  and age and sex groupings a r e g i v e n i n T a b l e 8,  (Table  7)  were c a l c u l a t e d as suggested by Deevey  d y i n g d u r i n g t h i s p e r i o d t h e mean l i f e somewhat lower t h a n the v a l u e o f 7.06  L i f e expectancies  (1947:2814.-285).  expectancy i s 5*6  years.  could s i g n i f y t h e two  a  fundamental  For sheep This i s  c a l c u l a t e d by Deevey (op. c i t . :289)  6 0 8 D a l l sheep (Ovis dj_ d a l l i ) s k u l l s c o l l e c t e d by Murie  for  of  tend  (1944).  This  d i f f e r e n c e i n the n a t u r a l m o r t a l i t y patterns  s p e c i e s , b u t i s more l i k e l y due t o the e f f e c t o f h u n t i n g o f the  Ashnola herd. The mean annual m o r t a l i t y r a t e has been c a l c u l a t e d by d i v i d i n g t o t a l o f t h e column o f t h e number o f i n d i v i d u a l s d y i n g i n each age  the group  (dx) by the t o t a l o f t h e column o f i n d i v i d u a l s a l i v e i n each age group and m u l t i p l y i n g t h e p r o d u c t by 1 0 0 . (16.5  lambs were censused, and i n a p o p u l a t i o n o f 250  t h i s r e p r e s e n t s an increment o f 18  percent.  A l t h o u g h the n a t a l i t y  m o r t a l i t y d a t a r e p r e s e n t d i f f e r e n t time p e r i o d s , t h e i r s i m i l a r i t y suggests h e r d s t a b i l i t y .  each age group remained  In animals and  strongly  I n c a l c u l a t i n g the mean annual m o r t a l i t y r a t e i t  has been assumed t h a t the p o p u l a t i o n was in  x  In a stable population t h i s value  p e r c e n t ) s h o u l d be e q u a l t o t h e mean annual replacement r a t e .  I 9 6 0 a t o t a l o f 45  (l ),  constant.  s t a b l e and t h a t the number o f sheep  Both assumptions  are open t o  criticism.  38  TABLE 7 LIFE TABLE FOR THE CALIFORNIA BIGHORN BASED ON THE KNOWN AGE OF DEATH OF 57 INDIVIDUALS PRIOR TO l?6l (BOTH SEXES COMBINED)  X  Age (years)  0-1 1-2 2-3 3-4 4-5 ..' 5-6 6-7 7-8 ^8-9  9-10 10-11 11-12  <*x  Ix  Number out of Number out 1000 born surviving at of 1000 born dying i n age beginning of interval age interval  228 53 35 53 17  53 11*0 88 Iho  88  70  35  1000 772  719 684 631 6lU 561 421 333 193  105 35  M  Percentage mortality during age interval  22.8 6.7 4.9 7.7 2.7 8.6 25.0 20.9 42.0 45.6 66.7  100.0  Mean annual mortality rate - 16.5 percent  e  x  Expectation of l i f e , or mean life-time remaining to those attaining age interval  5.6 6.1 5.5 4.7 4.1 3.2 2.4 2.1 1.5 1.2 0.9 0.5  39  The survivorship curve of Figure 21 indicates a mortality pattern characterized by high lamb mortality, lower mortality in the age groups between 1 and 6 years of age and high mortality in the older age groups. The curve is similar to that presented by Deevey (op. cit. :291) for Dall sheep and i s definitely not of the positively skewed type. The major difference between Deevey's data and that for the Ashnola sheep is the age at which heavy mortality in the older age groups begins. Mortality increases sharply in the 6-7 year age group for the Ashnola, but in the Dall sheep not until about 9 years of age.  This discrepancy however, may only be a  function of human exploitation of the Ashnola herd. Table 8 has been prepared largely to compare age and sex of sheep at death in the Ashnola with that of $0 skulls collected by Sugden (1961) for the same subspecies of bighorn sheep in the Churn Creek watershed, British Columbia. Sugden has. followed Maries' (op. cit.) classification of Dall sheep and considers lambs and yearlings immature, 2-8 year-olds as prime, and 9 and older as senile.  Data presented this way, especially Sugdens',  do not suggest such strong age selection by agents killing sheep. This may only mean however that we should reconsider what is prime and what is not. Sugden does^not; mention the effect that perishability of lamb skulls or hunting for rams might have on his data ( trwj 0  Table 8 also indicates that a mortality difference in the sexes may exist, with rams outliving ewes. Both Sugdens (op. cit.) and Muries' 1  (op_. cit.) data suggest a similar pattern. Of 2k females of the Ashnola herd whose age at death was determined with reasonable accuracy, the oldest was 10 years and the average was 6 years. Churn Creek ewes averaged k  SURVIVORSHIP  6  12  8  13  CLASS  < FIGURE  7  21.  MORTALITY BIGHORN  AND  SURVIVORSHIP  SHEEP  HERD.  CURVES  DATA FROM  FOR  THE  TABLE  7.  ASHNOLA  ho TABLE 8 AGE AND SEX OF SHEEP THAT DIED ON  l?6l  ASHNOLA RANGES PRIOR TO JUNE,  Number of animals Lambs and Yearlings  Sex Male Female Undetermined Totals Percenti:;G  of  total  Ashnola Churn C r .  1-Data from Sugden  years of age at death.  2-8  9 years and older  Totals  6 2 7  12  8  26  19 0  3 0  2k  15  31  11  57  54.5  19.0 10.0  26.5 1  Years  20.0  70.0  7  1961:66. Since the rate of population increase i s i n part  dependent upon longevity o f the ewes, a shortened ewe l i f e span could greatly retard t h i s r a t e .  Dispersal Census figures and age r a t i o s indicate that the Ashnola bighorn herd i s r e l a t i v e l y stable, or at most, increasing very slowly.  This can be  accounted f o r by m o r t a l i t y within the area, by dispersal from the area, or by both of these factors working together. L i t t l e evidence has been found f o r dispersal from the area.  However  two observations of bighorn sheep on the north side o f the Similkameen r i v e r have been made recently by l o c a l residents•  In November 1959  a mature ram  was seen on the Green Mountain road about 10 miles north o f Keremeos, and also i n the f a l l o f 1959  a mature ram was observed near Shuttle Creek, about  2 miles north o f Keremeos.  These rams had l i k e l y dispersed from the Ashnola  la herd.  Later the same winter a large ram was also seen on the south shore  of the Similkameen River, and appeared to be seeking a crossing place.  It  is notable that a l l of these observations were of lone, mature rams, and were made during the f a l l and winter.  Small ram groups have also been  reported south of the Similkameen at Wolfe Creek and Bromley Rock, both just east of Princeton and a considerable distance from the main Ashnola ranges. Since there are s t i l l suitable bighorn wintering areas within their original range north and east of the Similkameen River i t is reasonable that sheep dispersing from the Ashnola would occupy these.  No breeding  populations have been seen on these ranges since the l ° 2 0 ' s however.  Dis-  persal to the west would be unlikely due to lack of suitable wintering ranges.  It seems more l i k e l y that the sheep would disperse f i r s t from the  most populated winter-spring range (South Slope) on to areas already occupied by sheep, but i n lesser numbers (e.g. Crater Mountain). The ram observations north of the Similkameen indicate that the Ashnola population has reached a level where a few of the least social members of the population w i l l disperse.  Due to the highly social nature of ewe-yearling-  lamb and young ram groups and their tendency to occupy traditional ranges and escape terrain, the Similkameen Valley at present provides enough of a barrier to prevent dispersal of such groups from the Ashnola watershed. LIMITING FACTORS Since the Ashnola bighorn herd is not losing members due to dispersal, and the natality rate is sufficient for rapid population increase, one or more mortality factors must be operating to limit population increase. According to Leopold (1933), "The limiting factor i s the one which has to be moved f i r s t , and usually the one to which the application of a given  k2 amount of e f f o r t -will pay the highest returns, under conditions as they stand*"  Sound management of a game population l a r g e l y involves determining  the l i m i t i n g factor and c o n t r o l l i n g i t .  The following presentation and  discussion of data should throw l i g h t on the population l i m i t i n g f a c t o r i n the Ashnola bighorn herd.  Food I n s u f f i c i e n t food, more than any other factor, has been found to l i m i t populations o f montane ungulates.  Lack  (195U) suggests that i t i s food  shortage which l i m i t s mammal populations i n general.  I t should be r e a l i z e d  that i t i s often d i f f i c u l t to separate the various factors causing m o r t a l i t y i n an animal population.  For example, a bighorn sheep might be suffering  from malnutrition and so contract a disease thus being further weakened and caught by a predator.  The observer may  detect only the l a s t of these events  and conclude that predation i s an important l i m i t i n g f a c t o r .  Because of  such d i f f i c u l t i e s many i n d i r e c t evidences must be used to determine which mortality factors are c r i t i c a l . I t should be noted here that food can be l i m i t i n g both i n quantity and i n q u a l i t y .  In t h i s study only quantitative aspects o f food supply  have been treated i n d e t a i l . Range Forage Competition I n t e r s p e c i f i c competition has been defined as "the demand of more than one organism f o r the same resources of the environment i n excess of immediate supply" (Larkin,  1956).  Thus i n determining competition between bighorn  sheep and other species, three phases o f study are necessary.  The degree  of competition w i l l depend upon, ( l ) the extent to which the bighorn sheep and other species graze the same areas, (2) the same forage species, and (3)  the extent to which they prefer  the supply o f preferred forage i n r e l a t i o n  43  to the number of grazing animals.  I f forage is plentiful, the animals are  essentially not i n competition for i t .  But as soon as overutilization of  the important species begins, forage competition begins, and this  affects  management of the range. Most studies of bighorn sheep on ranges used by other big game species or domestic stock have disclosed some degree of competition for forage between the sheep and one or more associated species (Cowan, 1947, Smith, 1954, Sugden 19&1).  Mule deer, cattle, domestic sheep, horses and mountain goats,  at one place or another, have occupied the same ranges as bighorn sheep i n the Ashnola.  Domestic sheep no longer graze the area and goat use is  n e g l i g i b l e , therefore these species can be safely disregarded as presently competing with the bighorn sheep.  Range use by horses, although not yet  serious, is increasing yearly. Competition with Cattle General Pattern of Range Overlap Due to the great r e l i e f of this area, cattle grazing has an altitudinal basis.  Turnout time is presently late April or early May but was April 1  in past years.  At this time cattle are herded up the Ashnola road and  turned loose above the pole bridge (mile 6 ) on the Ashnola Road. On Crater Mountain the cattle have been allowed to drift upward at their own speed.  On May 1 , 1961 most of the cattle on Crater Mountain were  already at the 4000 to 4,500 foot level, grazing the grassland slopes used as sheep winter-spring range.  Since the Crater Mountain ranges are rela-  tively contiguous, cattle here were not herded from range to range as on the east side of the Ashnola River.  From July to September these cattle  grazed chiefly i n the lower alpine area and i n openings i n the spruce zone. One hundred ninety cattle are pastured on Crater Mountain ranges.  kh  About 150 c a t t l e graze sheep ranges east of the Ashnola River.  Until  mid-May they graze l a r g e l y the steep dry Douglas f i r slopes below iiOOO feet i n elevation.  They are then herded on to the Starvation-Flatiron area where  they use these slopes and the adjacent Douglas f i r region u n t i l herded on to Juniper Slope and South Slope i n early June. grazed u n t i l about July 1,  The l a t t e r two ranges are  when the c a t t l e are moved into the Subalpine zone  and proceed from there into the alpine-subalpine f r i n g e .  From about mid-  September to mid-October the bighorn sheep winter ranges are again grazed by c a t t l e as autumn storms force them from the subalpine zone. Indian-owned c a t t l e are herded d i r e c t l y into the subalpine meadows around Red Mountain, Twin Buttes and Haystack Lakes i n early July.  A total  of 150 c a t t l e graze these ranges which are l a r g e l y forested and not extensive.  These c a t t l e do not graze bighorn sheep winter ranges. The above patterns of c a t t l e movement have been somewhat generalized.  A c t u a l l y herd management i n the form o f s a l t i n g , r i d i n g , and the use of fences varies from year to year i n accordance with y e a r l y trends i n range condition.  ^  As can be seen i n Figure 19 almost 70 percent o f the bighorn sheep winter-spring range i s occupied by c a t t l e to some extent, while less than 25 percent of the summer range i s used.  The winter range overlap i s proba-  b l y more extensive than indicated by Figure 19 since the cows stay mostly on the open grassland slopes which are also preferred sheep habitat.  Since  the cows only graze a small part of the bighorn sheep summer range and are on t h i s only f o r two and one h a l f to three months, competition on these ranges i s s l i g h t .  Also, the sheep on t h e i r summer range were observed to  graze more i n the true alpine than the subalpine zone, e s p e c i a l l y early i n the summer, while c a t t l e grazed c h i e f l y the subalpine zone.  k$ The range competition problem then i s b a s i c a l l y one o f spring and f a l l u t i l i z a t i o n by c a t t l e of sheep winter-spring ranges. Areas Grazed on Winter Ranges Although c a t t l e d i s t r i b u t i o n i n general covers most o f the sheep winterspring range, p e c u l i a r i t i e s i n microtopography  prevent much o f the area  from being grazed appreciably. A thorough survey was made of the South Slope range a f t e r summer c a t t l e use i n i 9 6 0 , to determine how much o f a t y p i c a l C a l i f o r n i a bighorn sheep winter-spring range was a c t u a l l y i n t e n s i v e l y used by c a t t l e . P a r a l l e l l i n e - p l o t transects were run the entire length o f the slope four hundred yards apart, at r e l a t i v e l y constant elevation.  Two c i r c u l a r  one hundredth acre plots were located mechanically every two hundred yards along the transects. On the plots cow droppings and sheep p e l l e t groups were recorded, and percent forage u t i l i z a t i o n was estimated from bunchgrass heights.  Steepness of slope and a c c e s s i b i l i t y were also recorded.  Since  a small amount of the forage u t i l i z a t i o n was by sheep i n the spring, u t i l i zation i s probably not as i n d i c a t i v e o f c a t t l e d i s t r i b u t i o n as number o f cow-chips.  A t o t a l o f f i f t y s i x paired plots were sampled and the pairs  were averaged f o r f i n a l  figures.  Tables 9 and 1 0 summarize data on the use o f South Slope by c a t t l e and bighorn sheep.  Cow droppings were much more prevalent on f l a t areas than  on the steep slopes.  Julander and Robinette ( 1 9 5 0 ) likewise found that  degree o f slope greatly influenced c a t t l e d i s t r i b u t i o n .  Sheep droppings  were not as common on f l a t areas as on the steeper slopes.  Observations  throughout the year substantiate t h i s pattern o f sheep use. Forage species on the small area o f r e l a t i v e l y f l a t t e r r a i n were u t i l i z e d more heavily than on the steeper slopes.  This was substantiated  he  TABLE 9 VARIATION IN FORAGE UTILIZATION BY CATTLE AND IN NUMBERS OF COW AND SHEEP DROPPINGS WITH DEGREE OF SLOPE ON THE SOUTH SLOPE RANGE, AUG. i 9 6 0  Slope (in degrees)  ]0-l$  ^Number of Plots  9  15-30  23  30 plus  2k  Percent of Area  Average Percent Utilization  Cow Droppings Per Acre  50 16 11  170 U8  16 ia U3  9k0  Sheep Droppings Per Acre 2ii5 540 45o  TABLE 10 UTILIZATION CLASSES FOR SOUTH SLOPE AFTER SUMMER GRAZING BY CATTLE, AUG. i 9 6 0  Percent U t i l i z a t i o n 0-25 Number o f Plots Percent o f Area  ko 71  25-50 5 9  50 plus 11 20  47 by observed c a t t l e d i s t r i b u t i o n .  The(graziers placed s a l t blocks only on  f l a t areas and since cows are w e l l known to be "creatures of habit", they stayed on these areas even after the forage was depleted, e s p e c i a l l y i f shade and water were nearby.  Only 20 percent o f the area showed 50 per-  cent or more forage u t i l i z a t i o n .  Julander  (1958)  delimited areas of  intensive use by c a t t l e on the basis o f 50 percent or more u t i l i z a t i o n o f grasses supplemented by cow-chip counts.  On t h i s basis, only a small part  of the South Slope range was used i n t e n s i v e l y by c a t t l e i n  i960.  Forage Preferences A knowledge of the forage habits o f the grazing animals i s essential i n the multiple-use management o f the Ashnola ranges.  Cattle food prefer-  ences were determined by counting grazed stems on t h i r t y plots a f t e r summer grazing.  immediately  Bighorn'sheep food habits were studied by direct,  observation of feeding animals, t r a i l i n g animals i n the snow, analysis o f rumen contents and spring grazed stem counts.  Sheep i n t h i s herd are  d i f f i c u l t to approach c l o s e l y and bighorn sheep i n general are delicate feeders selecting small portions of plants here and there.  By d i r e c t  observation i t i s d i f f i c u l t to i d e n t i f y much more than general classes of vegetation being used, therefore the animal-minutes grazing technique (Mosby,  1960:13:9)  was considered i m p r a c t i c a l f o r a refined analysis o f  sheep forage preferences. Grazed stem counts as a measure of forage u t i l i z a t i o n have been severely c r i t i c i z e d (Pechanec,  1936),  since a l l grazed stems are not grazed  to the same l e v e l , and d i f f e r e n t species which are grazed to the same l e v e l may  contribute m a t e r i a l l y d i f f e r e n t forage volumes.  In t h i s study the  grazed stem technique has been used however, only to determine the extent to which sheep and cows prefer the same species, and not as a measure of  48 volume percent of d i e t contributed by the various species.  Since the  technique has been applied to both sheep and cow use, the above errors should l a r g e l y be compensating. Since i n t e r s p e c i f i c competition f o r food can only occur on areas grazed appreciably by both species, forage preference determinations should be l i m i t e d to such areas.  Counts of stems grazed by c a t t l e were l i m i t e d to  areas of estimated Uo percent c a t t l e u t i l i z a t i o n .  .0004  acre portable quadrat during July  sheep were made i n May 1961  i960.  T a l l i e s were made i n a  Counts o f stems grazed by  to determine winter preferences and were l i m i t e d  to forage which matured the previous summer.  Stems grazed by sheep and by  cows could not be d i f f e r e n t i a t e d , therefore those grazed by sheep had. to be counted on areas inaccessible to c a t t l e .  Areas were selected o f s i m i l a r  botanical composition to the areas grazed by cows. meter quadrats were established on such areas.  Thirty, one-square-  Forage preferences determined  by grazed stem counts are presented i n Table 11. Other techniques have been applied to supplement the grazed stem counts as a measure o f bighorn forage preferences.  Daring December  i960,  after a  fresh f a l l of snow, sheep were t r a i l e d on South Slope and forage species u t i l i z e d by them were recorded where the sheep had pawed through the snow and f e d .  A u t i l i z e d plant was recorded as one feeding observation.  This  method does not necessarily provide a quantitative measure of the various plants represented i n the animals d i e t .  Data obtained using t h i s technique  are presented i n Table 12. Six one-pint samples of rumen contents were obtained from sheep between May  I960 and  May  1961.  These were washed and screened.  Only the  plant material which remained on a number ten screen a f t e r moderate washing was used f o r quantitative a n a l y s i s .  Relative composition was  determined  U9 by separating the material by species and measuring the volume of wet plant material i n a graduated cylinder.  Because of the range o f time and place  over which the stomach contents were c o l l e c t e d the r e s u l t i n g data are not u s e f u l i n the study o f sheep-cattle competition, but o f f e r a good i n d i c a t i o n of general sheep food habits i n the area.  Data obtained from rumen  sample analyses are shown i n Table 13* Spring food habits of sheep on South Slope during June were also determined by counting grazed stems and leaves i n twenty, one quadrats.  The quadrats were randomly placed on areas observed to be  grazed by sheep during the spring. recorded.  square-meter  Only grazing of new spring growth was  The short period of grazing by sheep on spring growth on South  Slope should not materially a f f e c t the competition r e l a t i o n s h i p .  Spring  food-habits data are given i n Table lit • Composition o f c a t t l e diets on the South Slope range and bighorn diets (on South Slope also except f o r stomach analyses) are compared by classes of vegetation i n Figure 22.  The most r e l i a b l e comparison of forage  preferences on which to base i n t e r s p e c i f i c competition i s that of the c a t t l e grazed stem counts with the winter grazed stem counts and t r a i l i n g observations f o r the bighorn sheep.  The winter grazed stem counts f o r the  sheep represent food habits from the time they return to the winter range i n October u n t i l about A p r i l when new growth begins.  This i s the period  over which South Slope i s grazed most heavily by sheep, and the period when the effects of malnutrition are l i k e l y to be most pronounced.  The  t r a i l i n g observations are also a good i n d i c a t i o n of general winter d i e t . On South Slope, grass, p a r t i c u l a r l y bluebunch wheatgrass, l a r g e s t part of the d i e t of c a t t l e . though r e l a t i v e l y abundant.  forms the  Chamaephytes were eaten l i t t l e a l -  Forbs also were unimportant i n the c a t t l e d i e t ,  50  TABLE 11 CATTLE AND SHEEP FORAGE PREFERENCES ON THE SOUTH SLOPE RANGE (DIET FIGURES ARE PERCENT OF TOTAL FORAGE CONSUMED BY EACH CLASS OF ANIMAL AS DETERMINED BY THE GRAZED STEM TECHNIQUE)  CATTLE  SHEEP  Grazed stems Percent o f d i e t Grazed stems  Agropyron spicatum 10,594 Koeleria c r i s t a t a 2,227 Poa sp 1,874 Festuca idahoensis 62 S t i p a columbiana 568 S. Richardsoni Bromus tectorum 7 Lupinus sp. 31 Achillea millefolium 74 Erigeron sp. 103 Antennaria sp. 6 Arabis sp. 20 Phacelia sp. 29 Artemisia f r i g i d a 142 Eriogonum heracloides 119  66.8 14.0 11.8 0.4 3.5 0.2 o.5 0.6 0.1 0.2 0.9 0.8  Percent o f diet  3,397 482 244 248  49.4 7.0 3.5 3.6  22 18 205 58  0.3 0.3 3.0 0.8  1,925 275  28.0 4.0  51  TABLE 1 2 BIGHORN FOOD HABITS ON SOUTH SLOPE IN DECEMBER I960 AS DETERMINED BY TRAILING SHEEP IN NEWLY FALLEN SNOW  Species  Agropyron spicatum Poa sp. Koeleria c r i s t a t a Agrostis sp. i ^ ( • , Stipa columbiana Broraus tectorura Erigeron sp. Lupinus sp. Achillea millefolium Artemisia f r i g i d a Eriogonum heracloides Ribes cereum Rosa sp. Artemisia dracunculoides ,  No. o f Observations  57 30 6 11 6 3 5 12 4 106 11 1 1 1  Percent of d i e t  22.4 11.8  2.4 4.3 2.4 1.2 2.0 4*7 1.6 4l.7 4.3 0.4 0.4 0.4  52  TABLE 13 COMPOSITION OF 6 RUMEN SAMPLES OF BIGHORN SHEEP COLLECTED ON ASHNOLA RANGES  Occurrence by volume percent in each sample* FOOD ITEM  1  Graminaea Artemisia frigida Eriogonum heracloides Lupinus sericeus Salix sp. Pinus contorta Arctostaphylos uva-ursi Erigeron sp. Achillea millefolium Potentilla sp. Vaccinium sp. Ribes cereum  9k  tr. tr. tr.  3  4  5  6  71 21  91 2  92  93 tr.  7  5 tr.  72 15 12  tr.  tr.  2  tr. tr.  k  3  k  tr.  tr. tr. 2  tr.  k  SEX AGE DATE  female male male female male male 10 yr,. 8 yr. . 7 yr.yearl. 8 yr. • 5 yr, 5-259-249-25- 3-13Apr./  LOCATION  South Sub- Sub- South South Slope alpine3 Alp. Slope Slope 6 , 5 0 0 ' '6,700 • 4 , 8 0 0 ' 6 , 2 0 0 ' Killed HunterHunt-- Co11.Winter k i l l er by No. 1 k i l l black kill bear  REMARKS  60  60  6o  61  61  •*tr. denotes less than 1 percent occurrence  5-11-61  Starvation Slope  4,5oo'  Coll. No. 2  Average Volume Percent 85 8  k 2  tr. tr. tr. tr. tr. tr. tr. tr.  53  TABLE lit SPRING?FOOD HABITS OF BIGHORNS ON SOUTH SLOPE DETERMINED FROM GRAZED STEM COUNTS  Species Agropyron spicatum Koeleria c r i s t a t a Poa sp. Stipa columbiana Festuca Idahoensis Bromus tectorum A c h i l l e a millefolium Allium cemuum Phacelia sp. Artemisia f r i g i d a Eriogonum heracloides Ribes cereum  No. o f Grazed stems  l,82u 708 617 10 9 516 75 4 9 45 23 4o  Percent of d i e t 47.1 18.3 15.9  0.2 0.2  13.3 1.9 0.1  0.2 1.2  0.6 1.0  CATTLE  FIGURE  22.  A  BIGHORN  BIGHORN  COMPARISON S H E E P  OF  DIETS  SUMMER BY  SHEEP  CATTLE  CLASSES  OF  DIET  WITH  SEASONAL  VEGETATION.  Sh l a r g e l y because they are not abundant (Table 11  and Figure 22).  Grasses  are also important i n the winter d i e t of the sheep, although displaced to a great extent by chamaephytes, p a r t i c u l a r l y pasture sage.  The l a t t e r was  observed to be a c t i v e l y sought out by sheep, e s p e c i a l l y early i n the winter. At this time many of the pasture sage leaves are not cured and dried as are most grasses and forbs.  Certain cured forbs such as lupines and yarrow  were also preferred by sheep, resulting i n the larger forb class f o r sheep than f o r c a t t l e .  Forage competition between sheep and c a t t l e on t h i s range  then, l a r g e l y involves competition f o r grasses, on only about 20 percent of the range area. Figure 22 also shows pronounced seasonal differences i n sheep d i e t . Pasture sage and bluebunch wheatgrass were the plants most often eaten i n winter.  These made up 35 percent and 36 percent of the d i e t respectively.  As winter proceeded the pasture sage became depleted.  Therefore the Decem-  ber (early winter) t r a i l i n g observations show a higher percentage of t h i s species than the o v e r a l l winter picture from grazed stem counts.  Sheep  were often observed to paw through several inches of snow to obtain pasture sage when abundant bunchgrass protruded above the snow.  Sugden  (1961)  using the snow-trailing technique found pasture sage to make up 48 percent o f the winter d i e t o f C a l i f o r n i a bighorns i n the Churn Creek basin of B r i t i s h Columbia. d i e t , but  Ashnola bighorn sheep averaged Sh percent grass i n t h e i r winter  72  percent over the fall-winter-spring period.  Couey  (1950)  found  that the stomachs of s i x bighorn sheep which died i n l a t e f a l l and winter contained an average of 63 percent grass. average 81.5  Murie  (I9hh) found grasses to  percent of the fall-winter-spring diet of D a l l sheep i n Alaska,  somewhat higher than Ashnola f i g u r e s . With the advent of new spring growth, the amount of grass i n the sheep  55 d i e t r i s e s sharply while pasture sage decreases.  The r e l a t i v e amount o f  bluebunch wheatgrass i n the grass class also decreases.  Cheatgrass, which  matures very early, was only eaten by sheep i n May and early June. The rumen sample data, being a mixture o f spring and early f a l l d i e t s ,  fall  between the winter and spring diets o f Figure 2 2 with respect to r e l a t i v e amounts o f grass and chamaephytes eaten. Shrubs were not important i n the sheep d i e t at any time o f the year. The chamaephyte and shrub class i n bighorn sheep diets of Figure 2 2 consists almost e n t i r e l y o f pasture sage, a chamaephyte.  The only true shrub  occurrences i n the quantitative determination o f sheep food preferences were 1 percent squaw current i n the June diet,and traces o f Kinnickinik, blueberry, and willow from the rumen samples. Many minor items not recorded i n Tables 1 1 to lit were eaten by sheep from time to time. and Spruce.  In the winter, sheep were seen nibbling at Douglas f i r  Ram groups i n the spring were observed eating Soopolallie,  Hudson Bay current (Ribes hudsonianum) and red raspberry (Rubus idaeus). Sheep were never observed eating juniper although i t occurs commonly around the margins o f South Slope. Balsamroot i s believed to be a major spring food item o f sheep on Crater Mountain ranges, but does not occur on ranges east o f the Ashnola. Cows and deer also ate balsamroot during i t s early growth stages.  Death  camas (Zygadenus venenosus), a species highly toxic f o r domestic stock, was eaten by sheep i n the spring with no observed i l l e f f e c t s .  The seed  pods o f lupines, many species o f which are poisonous f o r domestic sheep (Sampson, 1 9 5 2 ) were eaten during the winter. Not enough observations were made on summer ranges f o r an accurate quantitative analysis o f sheep summer d i e t s .  Species eaten were determined  56 by examining areas on which sheep had been seen feeding.  The following  plants known to be u t i l i z e d are presented approximately i n order of amount of use:  sedges (several species), grasses (Festuca ovina, Poa alpina,  Danthonia intermedia), woodrush (Lugula sp.), forbs (Lupinus sp. , C a s t i l l e j a sp., P o t e n t i l l a f l a b e l l i f o l i a , Astragalus sp., Silene douglas&i, Silene a c a u l i s ) , shrubs (Salix sp., Vaccinium scoparium, Arctostaphylas uva-ursi).  Mosses and lichens were never observed to be taken by sheep.  Degree of U t i l i z a t i o n I f the supply o f a forage species used i n common by the c a t t l e and bighorn sheep i s inadequate  f o r the requirements  be a c o n f l i c t f o r that species.  of both species there w i l l  A c t u a l l y the c o n f l i c t does not begin u n t i l  the u t i l i z a t i o n o f a species reaches the point that i s considered  "proper",  because up to that point there i s available forage f o r either or both to take as they choose.  From the food habits data i t i s evident that, on the  area grazed intensely by both c a t t l e and bighorn sheep, bluebunch wheatgrass i s the forage species most s i g n i f i c a n t i n the d i e t o f both animal species. Sampson, (op. c i t . ) considers proper use f o r bluebunch wheatgrass as 50 percent of the current growth. Use standards f o r grassland ranges are commonly based on l e a f length or stubble height. heights (Table  The estimates o f percentage u t i l i z a t i o n based on stubble  10) show that a f t e r the c a t t l e l e f t South Slope i n July i960,  20 percent of the range was grazed to proper use or beyond. area, since i t i s the f i r s t to show forage competition.  This i s a key  This means that  upon return of the sheep to the winter range i n October, (disregarding a small amount o f l a t e summer regrowth) competition f o r wheatgrass had already begun on 20 percent of the range.  Competition f o r other preferred species  within the same area i s also l i k e l y .  57 Since competition f o r forage w i l l increase as the sheep graze the range through the winter u n t i l adequate new growth appears i n the spring, maximum u t i l i z a t i o n o f the range by the end o f winter should be measured. To do t h i s , f o r t y eight plots were randomly placed on South Slope and the heights of ten randomly selected wheatgrass bunches i n each p l o t were recorded and averaged.  Percent u t i l i z a t i o n by weight was read from a  smoothed curve constructed from the table of height-weight r e l a t i o n s o f bluebunch wheatgrass given by Sampson (op. c i t . :39k)»  The relationship  shows that 50 percent u t i l i z a t i o n (proper use) equals a stubble height o f 4«5 inches. Table 1 5 presents u t i l i z a t i o n classes f o r South Slope after combined summer c a t t l e grazing and winter sheep grazing.  At t h i s time, the area  which had received grazing to the l e v e l o f proper use or beyond had only increased by 5 percent (from 20 to 25 percent).  This indicates that during  the winter the sheep graze l a r g e l y the area not previously heavily grazed by c a t t l e .  The percent o f the area receiving 25 to 50 percent u t i l i z a t i o n  however, sharply increased by l a t e winter, while conversely the area of less than 25 percent u t i l i z a t i o n decreased.  The r e l a t i o n s h i p between u t i l i z a t i o n  classes on South Slope after summer c a t t l e grazing and after combined summer c a t t l e use and winter sheep use i s shown i n Figure 2 3 . I t seems reasonable that i f 20 percent o f the range has been grazed by c a t t l e u n t i l only a course stubble of k*$ inches or l e s s remains, that sheep w i l l feed on parts of the slope where more leafage i s present. The competitive i n t e r a c t i o n o f bighorn sheep and c a t t l e on Ashnola winter ranges i s further complicated by the f a c t that sheep and c a t t l e do not graze the ranges at the same time.  Forage a v a i l a b i l i t y , l a r g e l y  correlated with snow depth and condition, v a r i e s seasonally.  Since sheep  71  40 35  0- 2 5  25-50  50 +  PERCENT  UTILIZATION  AFTER SUMMER GRAZING BY CATTLE  FIGURE  2 3 .  AFTER  SUMMER  CATTLE  USE  UTILIZATION  UTILIZATION AND IS  CATTLE WINTER BASED  A F T E R COMBINED C A T T L E USE AND W I N T E R S H E E P USE  CLASSES USE  IN  BIGHORN ON  FOR  I960  SHEEP  STUBBLE  WHEATGRASS.  SOUTH AND  SOUTH  AFTER USE  HEIGHT  IN OF  SLOPE  COMBINED 1960-61. BLUEBUNCH  58 TABLE 15 UTILIZATION CLASSES FOR SOUTH SLOPE AFTER BOTH SHEEP AND CATTLE USE OF CURRENT BUNCHGRASS CROP  Percent Utilization  Stubble Height (inches) Number of Plots Percent of Area  0-25  25-50  50 plus  7.5 plus  4.5-7.5 17 35  0-4.5  19  ho  12 25  but not cattle use this range i n winter, i t i s only the former which are affected.  It has previously been stated that competition for bunchgrass  starts when the average stubble height i s reduced to 4.5 inches or less on combined cattle-sheep-use areas.  However i f bunchgrass of a height over  4«5 inches which has been grazed by cattle is unavailable to sheep because of snow cover, then competition for i t is occurring.  Unfortunately the  effect of snow depth and condition on forage availability is d i f f i c u l t to measure.  Figure 24 shows that the deepest winter snows on the South Slope  range are on the flatter areas such as the lower bench.  Since the flattest  areas are also heavily u t i l i z e d by cattle, they are the f i r s t to become unavailable due to snow cover. in the Ashnola.  This is typical of most sheep winter ranges  North slopes gather even more snow (Figure 24) but due to  dense forest cover are not important as range for either cattle or bighorn sheep.  Two factors then, deter winter sheep use of the flatter parts of  South Slope of  1960-61 was  heavy utilization by cattle, and deep snows. milder than average.  The winter  A severe winter would restrict the  sheep even more to the steeper slopes.  Whether the bighorn sheep would  use the flat areas i f abundant forage protruded above the snow is a matter  30  OCT  FIGURE  I  24.  NOV  SNOW  I  l  DEC  DEPTHS REGION  AT OF  JAN  I  SELECTED T H E  I  FEB  SITES  ASHNOLA  MAR  IN  VALLEY,  I  THE  APR  SOUTH  1 9 6 0 -6 1 .  I  MAY  SLOPE  59 of conjecture. Sumniary South Slope, the most important bighorn sheep wintering range i n the Ashnola region, was grazed by 1 5 0 c a t t l e f o r three weeks i n June I960. This was the only use the slope underwent by domestic stock i n i 9 6 0 .  Twenty  percent of the slope was grazed to proper use (50 percent u t i l i z a t i o n of bluebunch wheatgrass) by c a t t l e .  Eighty one percent o f a l l c a t t l e chips  were on areas of l e s s than 15 degrees of slope.  Only 20 percent of a l l  sheep droppings were found on areas of s i m i l a r slope*  Thus on t h i s range,  areas selected by c a t t l e and bighorn sheep were l a r g e l y d i f f e r e n t . Forage preferences o f c a t t l e and bighorn sheep were s i m i l a r with one exception.  Bighorn sheep ate an average of 35 percent pasture sage i n  winter, while c a t t l e d i d not u t i l i z e this species. After combined summer c a t t l e use and winter bighorn sheep use 25 percent of South Slope was grazed to proper use or beyond. The above facts disclose that competition on South Slope between c a t t l e and bighorn sheep f o r the forage crop o f i 9 6 0 was s l i g h t .  However i f South  Slope was grazed by c a t t l e i n the f a l l as w e l l as i n early summer, as has usually been the p r a c t i s e i n the past, c a t t l e would probably s t a r t u t i l i z i n g the steeper slopes and the area grazed beyond proper use would increase greatly.  I f adverse winter conditions with deep snows accompanied such  grazing practises, competition would be even more pronounced.  The f a c t that  forage competition i s s l i g h t however does not mean that the range could not support more sheep i f c a t t l e were removed.  This consideration w i l l be  discussed further with respect to land use competition. The data presented indicate that, because of s i m i l a r i t i e s i n forage habits, ranges such as South Slope can be l i t t l e more e f f i c i e n t l y u t i l i z e d  60  by grazing both cattle and bighorn sheep than by grazing either alone. Data on areas used indicates that, i f only one species is to be grazed on this range, sheep would u t i l i z e the range most efficiently since they graze the range more evenly than do the cattle.  To prevent continuing deteriora-  tion of these ranges, bighorn sheep and cattle numbers must vary inversely. Increased stocking demands by cattlemen, i f successful, can only be detrimental to bighorn sheep populations i n this region. Competition with Deer Deer use of bighorn winter-spring ranges i n the Ashnola i s largely from April to June, when new spring herb growth i s succulent and nutritious. As the higher ranges "green-up" the deer move upward, finally reaching the subalpine zone, and after late June are rarely seen on sheep wintering areas. Both deer pellet distribution and deer observations indicate that steepness of slope has l i t t l e effect on areas grazed by deer.  During winter  the deer were rarely found out i n the centre of large grassland slopes, but preferred to remain close to the forested margins or on flat areas at the bases of the steeper sheep-use slopes. the spring, but to a lesser extent.  This pattern was also exhibited i n  For this reason, the two species may  actually compete less than i s indicated by a direct comparison of sheep and deer numbers. A similar bighorn-deer relationship was found by Cowan (1947)  i n Jasper Park, Alberta.  Actual forage preferences of deer were not accurately determined. Examination of areas used by large numbers of deer i n May showed that deer ate most grasses and a wide variety of forbs at this time.  On May 2 1 , 1 9 6 1 ,  lkh deer were counted on Juniper Slope, grazing new growth i n the swales and low spots.  Unfortunately this grazing occurs during the early growth  stages when plants are damaged most easily.  Such heavy spring use may be  61  i n part responsible f o r the advanced successional stages o f such ranges as Juniper Slope and Starvation F l a t s , and c e r t a i n l y cannot be ignored as a long term factor i n bighorn sheep range competition. Winter deer diets are indicated by rumen content analyses given i n Table 16.  The sample i s small but believed to be i n d i c a t i v e of deer using  these ranges.  The deer were collected while grazing on or at the margins  of grassland sheep wintering ranges.  Food items making up 6$ percent of  the volume of these samples are also used extensively by sheep on winter ranges.  The only marked difference i n deer and sheep diets on the winter  ranges i s i n u t i l i z a t i o n of coniferous species by deer.  Although deer were  often observed eating Douglas f i r needles, only jackpine needles were found i n the stomachs examined.  Jackpine has not been recorded as an important  winter deer food by other workers. snow to obtain pasture sage.  Deer also were observed pawing through  Sugden (l?6l) found pasture sage to be the  dominant winter food of mule deer i n the Churn Creek basin of B r i t i s h Columbia. The volume o f the deer d i e t contributed by deciduous browse species i s small, p a r t l y because o f r e l a t i v e paucity of such species i n t h i s area, and p a r t l y because deer were only collected on grassland ranges.  Deer i n  timbered areas, burns and creek-bottoms were observed eating large quantiti e s of such available forage as Douglas f i r , juniper, willow and mountain maple. I t i s d i f f i c u l t to determine whether deer-bighorn competition i s actua l l y occurring since evaluation o f range misuse by deer i s complicated by c a t t l e grazing.  On ranges such as Juniper Slope the use of pasture sage  by deer seems heavy enough to affect i t s a v a i l a b i l i t y to bighorns.  Douglas  f i r , juniper, and willows show evidence o f heavy browsing i n the past,  62  TABLE 16 COMPOSITION OF THREE RUMEN SAMPLES OF MULE DEER COLLECTED ON ASHNOLA BIGHORN SHEEP WINTER RANGES  Occurrence by volume percent i n each sample*  FOOD ITEM  Gramineae Artemisia f r i g i d a Eriogonum heracloides Lupinus sp. Mahonia sp. Achillea millefolium Antennaria sp. Erigeron sp. S a l i x sp. Populus tremuloides Alnus sp. Pinus contorta SEX DATE COLLECTED LOCATION  1  2  22  35  16  15  0 20 0 8 0 tr. tr. 0 0 32  20 tr. tr. 0 2 0 0 5 0 22  Female  Dec. 28/60  Juniper Slope  Female Mar. 13/61 South Slope  3  16 28 k  10 0 0 tr.  0  0 0 tr.  39  Average Volume Percent  2k 20 8 10 tr. 3 1 tr. tr. 2 tr. 31  Male Apr. 17/61 Juniper Slope  Grasses 2k percent, Forbs 15 percent, Chamaephytes and shrubs 6 l percent. -*tr. denotes less than 1 percent occurrence.  63 presumably by deer.  Damage to what browse species e x i s t could modify deer  feeding habits toward competition with bighorn sheep, and i s a case f o r increased deer harvesting i n the area.  Deer on the Ashnola winter ranges  may only be eating large amounts o f pasture sage, grasses and forbs of necessity through lack of the t a l l e r browse species. Since deer numbers i n the Ashnola are presently increasing, additional demands on bighorn sheep winter range forage are l i k e l y to be encountered i n the near future. Competition with Horses As recreational use o f the Ashnola area increases, bighorn sheep-horse competition becomes more imminent. sheep i n  Most of the 80 hunters seeking bighorn  i960 had both saddle and pack horses with them. Numerous deer  hunters before and a f t e r the sheep season also brought horses on to Ashnola ranges.  One party o f ten men pastured f i f t e e n horses on Juniper Slope f o r  one week.  On the basis o f kO droppings per acre f o r horses and 1 6 0 p e l l e t  groups per acre f o r sheep, horse use o f Juniper Slope exceeded sheep use. I t was possible to t o t a l up, previous to the hunting season o f I 9 6 0 , horse grazing days i n the Joe Lake v i c i n i t y .  171  This use was attributed to  only the r i d i n g and pack animals of known parties of fishermen, game b i o l o g i s t s , sightseers, grazing permitees and agrologists (Smith, i 9 6 0 ) .  Fishing  at Cathedral Lakes also attracts many horseback v i s i t o r s to the area. to t h i r t y horses have been counted near these lakes at one time.  Up  Such horse  use i s d i f f i c u l t to control, since v i s i t o r s i n the area require no grazing permit. Dae to i n a c c e s s i b i l i t y o f much o f the alpine-subalpine zone, horsebighorn sheep competition i n such areas i s not l i k e l y to become serious. Horse use o f sheep wintering areas such as Juniper Slope, however, presents a d e f i n i t e threat o f sheep-horse competition.  This i s l i k e l y to worsen  6k with time. Animal Use of Several Ranges The detailed analysis of bighorn sheep-cattle competition has been limited to the South Slope range.  Large areas of most other Ashnola ranges  however, are also grazed i n common by bighorn sheep and cattle, but are not grazed beyond proper use. occurring but is incipient.  On such areas forage competition i s not As a basis for the evaluation of forage use  on Ashnola ranges i t is useful to compare the numbers of various ungulates using such ranges.  This has been accomplished both by pellet or chip  counts and by actual observation of numbers of grazing animals using the range units  0  Pellet counts on several ranges are summarized i n Figure 2$.  These  are most useful as a means of comparing grazing pressure by the same species on different ranges.  Sheep pellet groups per acre were much more  numerous on South Slope than on other ranges. distribution confirm this finding.  Observations of winter sheep  Deer pellet groups on South Slope were  much less numerous than those of sheep, but were more numerous than sheep droppings on Juniper Slope and Crater winter range.  Gow chips were most  numerous on Crater spring-use range, but were also abundant on South Slope and Juniper Slope.  Cow chips were not common on Crater winter-use ranges.  Land use competition on Ashnola ranges can also be compared on the  -8 -7 S  BIGHORN  D=  DEER  C -  CATTLE  H=  HORSE  SHEEP  - 6  -5  -4  -  1  0 S  D  C H  S  0  C H  S  UUNIPER  SOUTH S L O P E  HORSE  25.  DEER  CHIPS  ON  AND  (SPRING  SHEEP  SEVERAL  C  H  D  CRATER  SLOPE  FIGURE  D  PELLET  BIGHORN  RANGES.  H  CRATER  SHEEP USE)  GROUPS SHEEP  C  (WINTER S H E E P U S E )  AND  CATTLE  WINTER — S P R I N G  AND  65 basis of animal unit months.  Animal months are calculated by multiplying  the number of animals using a range by the number of months i n a year that they use i t .  Since this study chiefly concerns bighorn sheep, i t w i l l be  convenient to study comparative range use on the basis of sheep unit months. One sheep unit month (S. TJ. M.) can be defined as the use made of any particular range by one bighorn sheep of average weight, for one month. The term 'use' here implies forage u t i l i z a t i o n .  To determine S. U. M. 's  for other species i t must be possible to equate them to bighorn sheep on the basis of forage consumed.  Dr. A. J . Wood, Department of Animal Science,  University of British Columbia, has suggested equating five bighorn sheep or three mule deer to one cow on the basis of dry matter intake.  Sheep unit  months per acre have accordingly been calculated for bighorn sheep, deer and cattle use of South Slope, Juniper Slope, Starvation Flats and Crater Mountain ranges (Figure 26).  Total unit months per acre on South Slope  and Crater Mountain ranges are similar. Starvation Flats are much higher.  Totals for Juniper Slope and  The majority of use on the latter two  ranges is attributable to deer and c&ttle. use exceed that of other ungulates.  Only on South Slope does sheep  Sheep use per acre is also at least  two times greater on South Slope than on other ranges. also shown by pellet group counts.  This pattern i s  Deer use per acre is considerably  greater on Juniper Slope and Starvation Flats.  Deer pellet groups were  also greatest on Juniper Slope, but were not counted on Starvation. Deer use on Crater Mountain i s probably greatly underestimated by this technique because deer counts there were not made frequently, and the area i s very large.  Similarly cattle use on South Slope, based on numbers using the  area i n i960, i s probably underestimated because cattle are on the slope for a longer period of time i n most years.  LsJ CK O  SIGHORN  SHE!  D= D E E R C= C A T T L E  -3  UJ 0.  2: o  2  -I 0. UJ  S. Vi  S  D  C  SOUTH  SLOPE  FIGURE  2 6 .  WINTER  S  D  JUWIPER  USE  RANGES,  OF  C  S  SLOPE  SEVERAL  BASED  ON  D  C  S  STARVATION F L A T S  ASHNOLA  OBSERVED  UNGULATES,  C  CRATER M T N -  BIGHORN  NUMBERS  D  OF  SHEEP  GRAZING  66  On the ranges compared i n Figure 2 6 , bighorn sheep, deer and c a t t l e use contributed 2 . 0 , U»3,  and 8.7 S. TJ. M.  's per acre r e s p e c t i v e l y .  Since  these ranges are the most important sheep wintering areas i n the Ashnola, i t i s apparent that land use competition between bighorn sheep and other species i s extensive, even i f forage competition i s not.  Sheep numbers  can be increased only by reduction i n numbers of other herbivores on the range.  Optimum a l l o c a t i o n o f grazing capacity can be made only with due  regard f o r the physical, economic and s o c i a l factors involved.  Such factors  do not f a l l within the scope of t h i s study. Forage Production and Carryover Ten large animal exclosure p l o t s were erected during the spring of I 9 6 0 on edaphic climax grassland slopes known to be important as bighorn sheep winter-spring range (Figure 7).  These plots were b u i l t to provide control  areas f o r detecting y e a r l y trends i n forage production.  I t i s hoped i n t h i s  way to obtain a basis f o r the manipulation of numbers o f grazing animals. A secondary purpose was to provide permanent locations f o r long-term research on the cumulative e f f e c t on plant succession of grazing by c a t t l e and other ungulates.  The exclosures have only been i n place f o r one year, therefore  I can. only report on the trends i n forage production f o r this year. o f p l o t l o c a t i o n are summarized i n Table 17.  Details  Six of the ten plots were  randomly located on South Slope because of i t s ' importance as a sheep wintering area.  Because of uniformity i n botanical composition and condition,  smaller s i z e and l e s s sheep use, only one p l o t was located on each of Juniper Slope and Starvation F l a t s .  The two exclosure plots on Crater Mountain are  both on slopes used by sheep i n the winter only.  Due to the incomplete  knowledge of important sheep ranges at the time the exclosure plots were erected, no p l o t was put on the spring-use area of Crater Mountain.  No  67 exclosures were set up on the summer ranges*  General s i t e s were randomly  chosen,.''however plots were a c t u a l l y located where a large enough area of uniform plant density existed to allow l o c a t i o n of both the fenced and unfenced  plots,  Exclosures were constructed o f four foot high smooth wire c a t t l e fencing and seven foot i r o n corner posts. above the c a t t l e fencing. Figure 27.  One strand of barbed wire was strung  The plan view of an exclosure p l o t i s given i n  During cutting, a s t r i n g quadrat with spikes at the corners was  l a i d down i n s i d e both the fenced and unfenced plots dividing each into four equal areas.  Grass cut on each of these areas was  a i r - d r i e d and weighed.  The object of the exclosure studies i s control of a single f a c t o r of plant environment, namely grazing by large herbivors.  This implies that  the exclosure i t s e l f has no e f f e c t on the vegetation within the p l o t .  This  i s not l i k e l y the case however, since the exclosure fence w i l l promote the d r i f t i n g of snow and deposition o f dust, w i l l provide some shade, and w i l l i n t e r f e r e with normal a i r movement (Daubenmire, 19h0)»  The exclosure plots  are f a i r l y large and of the lowest and most open structure that w i l l possibly give the type of protection desired.  Therefore the effects of the b a r r i e r  on p h y s i c a l factors should be minimized. and out o f the exclosures.  Rodents could move f r e e l y into  None of the exclosures had inhabited rodent  burrows within the fences and no abnormal rodent use was made o f fenced areas. Since forage growth took place during and a f t e r c a t t l e grazed t h i s range, differences i n forage production between grazed and ungrazed plots ho+  should be used as a measure o f forage consumed by c a t t l e .  However the  primary purpose of these exclosure plots i s to determine the amount of forage that would be available f o r bighorn sheep winter use on various ranges i f no grazing by c a t t l e occurred.  This was done by clipping the plots  68  TABLE 17 DETAILS PERTAINING TO LOCATION OF LARGE MAMMAL EXCLOSURE PLOTS  Plot Date Number Erected 1  May  2  May 27,  I960  3  May 27,  I960  h  May 28,  i960  5  May 30, I960  26, i960  Location and Elevation  Nearest Transect  Starvation Slope,  11  Windswept knol on Juniper Slope, 5 , 5 0 0 feet. West end of South Slope, 5000 feet.  10  4,600 feet.  West end of South Slope, 4,300 feet.  1  2  Centre of South Slope, below large basin, 5000 feet. May 28, I960 Lower bench of South Slope, U000 feet. May 29, I960 Near crest of South Slope, 5,800 feet.  6  8  May 29, I960 East end South Slope, 4,500 feet.  8  9  June 1, I960  6 7  10  June 1,  I960  Crater Mountain, 4OO yards N. E. of Crater Creek. 5 , 2 0 0 feet. Crater Mountain, One mile N. E. of Crater Creek, 5000 feet.  5 7  lU 15  Remarks 10 to 15 degree slope. Near water and salt in spring only. 10 degree slope. Short distance to water and shade. 5 to 10 degree slope. 200 yards from timber and stream.  15 to 20 degree slope. On route between salt and water. 25 degree slope. Near water,csalt, and flat ground. 5 degree slope. Salt 50 yards, water kOO yards. 35 degree slope. Not easily accessible to cattle. 30 degree slope. One half mile to salt, 300 yards to water. 35 degree slope. Well terraced. 300 yards from water and shade. 35 degree slope. Not near salt, water, shade or flat ground.  •  UNFENCED  QUADRAT  6  WOODEN POST  I4 -+  13  —  SPIKE  4  DO  ^  *^  STRING QUADRAT"  O  <M  UNCUT MARGIN SMOOTH WIRE CATTLE FENCING (4' HIGH )  7  1 M  •  I RON  CORNER  I_  POST  FENCED  FIGURE TO  27.  PLAN  DETERMINE  VIEW THE  OF  A  EFFECT DUCTION  QUADRAT  LARGE OF  ON  MAMMAL  ANIMAL  ASHNOLA  EXCLOSURE  GRAZING RANGES-  ON  PLOT  FORAGE  USED PRO-  69 i n the f a l l , since effectively the only summer grazing i s by cattle* Table 18 summarizes forage production on the exclosure plots during the I960 growing season.  Large differences exist i n the weight of forage  produced by different plots.  The effect of grazing on differences i n  forage produced on fenced and unfenced parts of plots (grazing effect) also varied greatly from plot to plot.  A comparison of Tables 17 and 18 shows  that the latter difference is largely due to variations i n steepness of slope.  Plots 1, 3 and 6 for example, are a l l on areas of less than 15  degree slope and a l l show a pronounced grazing effect.  Plots 5 , 7, 8, 9  and 10 are a l l on sites of 25 degree slope or more, and mostly show very l i t t l e grazing effect.  Variation i n grazing effect on South Slope associ-  ated with accessibility to cattle is illustrated by Figures 28 and 29•  This  substantiates previous observations on cow chip distribution and observed cattle distribution. Forage production within fenced plots varied chiefly with successional status and edaphic factors.  Forage weights within exclosures varied from  l i b to 871 pounds per acre.  Lowest production was on plot 2 located on  Juniper Slope.  This plot is on a gravelly windswept knol (Figure 30).  Successional degeneration is also evident here, the predominant plant species being Sandburg bluegrass and pasture sage. tative of Juniper Slope i n general.  This exclosure is not represen-  A similar low production on fenced  plots, associated with advanced successional status, was evident on plots 1 (Starvation Slope) and 3 (South Slope).  Greatest forage production by  weight was on climax bluebunch wheatgrass range.  Plots 7, 8 and 10 are  most representative of the primitive climax condition and were the best forage producers.  The fenced area of plot 6 (Figure 31), although on a  flat, heavily grazed area, had a high forage production associated with  70  TABLE 18 FORAGE YIELD OF FENCED AND UNFENCED PLOTS ON ASHNOLA BIGHORN SHEEP WINTERING RANGES AFTER SUMMER GRAZING BY CATTLE, 1?60  Plot Number 1 2 • 3 k  5  6  7 8 9 10  Date Clipped Oct. 31, I960  Oct. Oct. Oct. Oct.  23, 10, 2U, 11,  I960 I960 I960 I960  Oct. 25, I960  Oct. 23, I960 Oct. 30, I960 May 18, 1961 May 19, 1961 Means  Forage Yield (Dry Matter) Grams Pounds per acre Fenced Unfenced Fenced Unfenced  200 901  302 11U 2U1 637 697  532 11U3  979 1127 219 1055  868 871 392 8ia  786  515  579  101 156  329 86U 9U7 1120 1178 1 1 8 U  79 159  81  3k6  82k  57 117 6'0 11*7  663  255 720 831  161 111  379  FIGURE 28. Exclosure plot no. 3 on South Slope at the 5000 f t . elevation. Relatively f l a t terrain and nearness to shade and water promote heavy cattle use. Dae to advanced successional state forage production i s low within the plot also. Compare with Figure 29*  FIGURE 29. Exclosure plot no. 7, at the 5,800 f t . elevation on South Slope. Note abundant growth of bluebunch wheatgrass both within and without the fence. This area i s not inaccessible to cattle but i s separated from f l a t areas by slopes of 30 to UO degrees.  FIGURE 30. Exclosure p l o t no. 2 on Juniper Slope at 5>.U00 f t . e l e v a t i o n . Sparse growth on t h i s windswept knol i s almost e n t i r e l y Sanburg bluegrass and pasture sage. The l a t t e r species i s extensively eaten by b i g horn sheep and deer i n the winter. This range i s overgrazed and i n poor condition.  FIGURE 31• Exclosure p l o t no. 6 on the lower bench o f South Slope, I4.OOO f t . e l e v a t i o n . This area i s heavily graaed by c a t t l e but forage production i s high. The vegetation here i s p r i m a r i l y a mixture o f bluebunch wheatgrass, Columbia needlegrass, junegrass and bluegrasses.  71  favorable s o i l and moisture conditions and a s l i g h t successional displaceThe Crater Mountain exclosures (Figures 32 and 3 3 )  ment from the climax.  vary s i g n i f i c a n t l y i n forage production and i n grazing e f f e c t although both are on climax bluebunch wheatgrass range.  These two plots were not clipped  u n t i l one year after t h e i r construction. Thus some of the grazing e f f e c t at p l o t nine i s thought to be due to winter sheep and deer use.  Plot 10,  even though on a slope frequented by sheep i n the winter, showed no cant difference i n forage y i e l d on fenced and unfenced areas.  signifi-  This suggests  that the Crater Mountain ranges could support more sheep than they do at present.  Observed sheep numbers on South Slope and on Crater Mountain  substantiate t h i s observation. On the area sampled by the ten exclosure p l o t s , a s i g n i f i c a n t difference existed i n forage y i e l d of fenced and unfenced parts of p l o t s .  An average  of 3 7 9 pounds of dry matter per acre remained on unfenced areas after summer c a t t l e grazing, while 5 7 9 pounds per acre was produced on the fenced control areas.  As a l l of these exclosures are on important winter-spring bighorn  sheep ranges, t h i s represents a considerable loss of forage otherwise able to bighorn sheep.  avail-  I f bluebunch wheatgrass i s considered representative  of the species used, forage competition d i d not generally occur on these ranges immediately upon return of the sheep i n the f a l l .  This i s because  50 percent u t i l i z a t i o n by weight (proper use) had not taken place by t h i s time. I t was intended to cut the unfenced areas of the plots again i n the spring of 1 9 6 1 to determine the amount of forage taken by overwintering sheep.  However due to the advanced state of new spring growth by the time  cutting was possible, only plots 5 and 7 , located on the upper part o f South Slope, were clipped.  These y i e l d e d 3 8 8 and 4 6 9 pounds of dry matter per  acre respectively, as compared with 6 6 3 and 720 pounds when cut i n October.  FIGURE 32. Exclosure plot no. 9 on Crater Mountain at the 5,200 f t . elevation. Although climax bluebunch wheatgrass i s the dominant species, forage production i s not high here. This slope receives considerable deer, bighorn sheep and cattle use. Note pronounced terracing.  FIGURE 33. Exclosure plot no. 10 at 5000 f t . elevation on Crater Mountain. Note the vigorous growth of bluebunch wheatgrass. Idaho fescue i s also abundant. Forage production was similar on the fenced and unfenced quadrats. Compare with Figure 32.  72  The difference is attributed almost entirely to grazing by bighorn sheep. These two plot sites, l i t t l e gra ed by cattle, are the most representative z  of winter sheep-use areas on South Slope. Thus on typical sheep-use slopes sheep consumed about 260 pounds of forage per acre over a six month period (mid-October until mid-April). This value would be somewhat less i f the entire South Slope was considered, since, as has been previously mentioned, the bighorn sheep graze the flat areas l i t t l e during the winter. The mean difference between forage weights on grazed and ungrazed parts of plots on South Slope when cut in October i960 was  2I4J4  pounds per acre.  This is representative of an area of about 600 acres. If differences in growth of forage on grazed and ungrazed areas are disregarded, this weight can be considered as the weight of forage consumed by cattle during their three week period on South Slope in i960. Thus the cattle, in three weeks, ate a volume of forage almost equal to that eaten by bighorn sheep in six months• Sheep and cattle use of South Slope can also be compared on the basis of sheep unit months. Cattle contributed £60 S. U. M.'s on South Slope in I960  while sheep use accounted for 720 S. U. M.'s.  These calculations  account only for use of the forage crop of i960. These figures are proportionately similar to figures for weight of forage utilized.  Sheep use was  somewhat higher when based on S. U. M.'s than when based on exclosure plot data. This is probably due to the fact that sheep graze more fringe areas than do the cattle, and therefore their grazing was not so much concentrated around the exclosure plots. In summary, the exclosure plot studies show that forage yield and carryover varies greatly with grazing pressure, successional status of the plant cover, and edaphic and climatic conditions. Forage production on  73 unfenced areas was s i g n i f i c a n t l y higher on the steeper slopes.  On the area  sampled by the ten exclosure p l o t s erected i n i 9 6 0 , 3k percent by weight of the dry matter present was consumed i n the summer of s i v e l y by c a t t l e .  almost exclu-  I960,  Thirty f i v e percent by weight was consumed by c a t t l e on  the 600 acre area of South Slope sampled by exclosure plots 3 to 8.  I t may  be concluded from t h i s data that s u f f i c i e n t carryover remained i n i960 to support the present sheep population through the winter.  On t y p i c a l sheep-  use areas of South Slope sheep u t i l i z e d 37 percent of the available dry matter.  Such u t i l i z a t i o n mostly occurred on areas l i g h t l y grazed by c a t t l e .  The data suggest that i f c a t t l e grazed South Slope f o r s i x weeks rather than three weeks, i n s u f f i c i e n t forage would remain to support the present popul a t i o n o f sheep using the area f o r the usual six-month period.  Parasites and Disease Many theories have been advanced i n an attempt to explain the causat i v e agents responsible f o r bighorn sheep mortality.  Foremost among these  i s the b e l i e f that parasites and disease are major f a c t o r s .  Normally  healthy bighorn sheep are commonly infected with both i n t e r n a l and external parasites without noticeable harm.  The i n f e s t a t i o n may become d e b i l i t a t i n g ,  however, i f there i s simultaneous and prolonged exposure to adverse weather, malnutrition, or over-crowded range conditions. There has been l i t t l e incidence of disease reported i n C a l i f o r n i a bighorn sheep i n B r i t i s h Columbia within recent years.  Epidemic  die-offs,  common among Rocky Mountain bighorns, do not seem to be c h a r a c t e r i s t i c mortality patterns i n the C a l i f o r n i a bighorn. were observed during the study.  of  Few u n t h r i f t y bighorn sheep  Several times sheep were heard coughing  during mid-winter, however, suggesting lungworm i n f e c t i o n .  Vigorous  scratching or rubbing of nearly a l l parts of the body was commonly witnessed,  74 p a r t i c u l a r l y i n l a t e winter and early spring.  This, along with the frequent  occurrence of magpies pecking on sheep, suggests the presence of i r r i t a t i n g external parasites.  The magpies often perched on the necks of sheep and  pecked them about the ears. the magpie was f i n i s h e d .  Such attended sheep usually stood s t i l l u n t i l  Considerable hair was pecked out a l s o .  Occurrence and abundance of parasites was determined by f e c a l analysis and post mortem examination. out the study.  Fresh sheep droppings were collected through-  Two adult sheep were also c o l l e c t e d .  Sheep droppings were procured p r i m a r i l y to determine incidence of lungworm larvae of the genus Protostrongylus. The droppings were put into paper bags i n the f i e l d , allowed to dry, and examined l a t e r i n the laboratory.  The Baermann technique f o r the i s o l a t i o n of helminth larvae, as  described by Cable (1958:153), was used to examine the droppings. droppings were broken apart, but not f i n e l y divided.  The  The only modification  of the technique was to allow the f e c a l sample to stand i n the water f o r twenty four hours, rather than the one h a l f to one hour suggested by Cable. Usually larvae d i d not s t a r t to appear u n t i l an hour or more a f t e r the sample was placed i n the water.  Quantitative determinations were made by  counting larvae i n a watch glass under a dissecting microscope.  The Baer-  mann technique i s only suitable f o r species i n which the larvae hatch before being passed i n the feces.  A few droppings were also examined with  the zinc sulphate c e n t r i f u g a l f l o t a t i o n technique (Cable op. c i t . ; l 5 o ) but no quantitative results were arrived a t . In seventy seven instances, f e c a l samples were gathered from bighorn sheep observed defecating.  The sex and age of these individuals was  recorded f o r future c o r r e l a t i o n with r e s u l t s from examination of t h e i r feces.  An additional twenty s i x fresh droppings were collected from  75 unclassified animals. Table 1 9 summarizes incidence of lungworm larvae from baermanization of fecal samples.  No significant differences i n percent of animals infected  were detected among rams, ewes and yearlings. lungworm larvae than older animals.  But lambs were freer of  This would be expected, however.  U6 percent of the lamb feces collected harbored lungworm larvae.  Only  The f i r s t  infected lamb dropping was collected on July 6 , i 9 6 0 , when the lamb was about eight weeks old.  Of sixteen lamb droppings collected i n July, eight  were infected and of seven collected from August I 9 6 0 to February 196l, 5 were infected.  This indicates that most of the lamb crop i s infected with  lungworms by early winter.  The earliest recorded date of lungworm larvae  in lamb droppings i s June 2 1 at Wildhorse Island, Montana, 1*7 days after the f i r s t lamb was born.(Forrester, I960). On the basis of the entire sample of 101 droppings, 80 percent of the population i s infected with lungworms. infected.  Excluding lambs, 88 percent are  Smith (195U) found 50 percent of the Salmon River bighorn sheep  herd i n Idaho infected with protostrongylin lungworms while Gouey (1950) found from 75 to 100 percent occurrence i n several Montana herds. The number of larvae passed by infected sheep varies greatly.  The  differences between lamb, ewe, and ram groups (Table 19) are thought to be real.  Fewer larvae per animal i n yearlings than i n lambs may be only a  result of sampling error. larvae than the adults.  Both groups however have significantly fewer This pattern i s further complicated by seasonal  variation i n larva output (Table 20).  Lamb droppings were not included  in Table 20 because lambs are i n the process of acquiring infection.  Nearly  a l l of the droppings from unclassified sheep were collected from November to January, therefore the average number of larvae is much larger for this  76 TABLE 19 PROTOSTRONGYLIN LARVAE OCCURRENCE AND INFECTION RATE BY AGE AND SEX GROUPS OF ASHNOLA BIGHORN SHEEP.  DATA FROM FECAL ANALYSIS  Av. No. Number of Larvae per gram o f feces No. o f Larvae GROUP  Sam- per gm. 0 1-10 11-50 51-100 101-250 250  pies  Lamb 24 Yearling 7 Ewe 21 Ram 23  Unclass.26 Total  101  feces  9.3  2.8 19.0 31.5 97.U  plus  11 8 1 6 4 12 3 9 1 6  4 0 2 8 4  0 2 1 7  20 41  18  11  1  0 0 1  1 6  0 0 0  46 14 19  2  4  54 86 81 87 96  20  80  1  8  Percent Not Percent Infected Infected  13  3  TABLE 20 SEASONAL PROTOSTRONGYLIN LARVAE OCCURRENCE IN FRESH BIGHORN SHEEP DROPPINGS COLLECTED ON ASHNOLA RANGES . 1  June-Aug• No. o f samples. Av. No. larvae per gm. feces.  40 19.3  ilamb droppings not included.  Sept.-Nov.  6 74.5  Dec.-Feb.  20 118.4  Mar.-May  11 10.1  77 group.  The -winter maximum of larvae output corresponds with the period  when environmental factors are l i k e l y to be most severe, and sheep i n t h e i r weakest condition. coughing.  I t was only during mid-winter that sheep were heard  I t has not been possible to correlate numbers of larvae with  degree of pathogenicity f o r the host.  Forrester (op. c i t . ) examined lungs  and droppings from f o r t y f i v e bighorn sheep and found no evident c o r r e l a t i o n between the degree of lung pathology and the numbers of larvae i n the droppings• Certain species of land snails serve as intermediate hosts f o r protostrongylin lungworms.  Two species o f s n a i l s were collected on Ashnola winter  ranges i n May l?6l, and have been i d e n t i f i e d as V a l l o n i a cyclophorella and a species of P a p i l l a .  These very t i n y s n a i l s were abundant on wet grass  and under pieces of wood and debris at the edge of South Slope while the ground was s t i l l wet from r a i n .  Pillmore ( i n Buechner i960:95) has found  V. cyclophorella and two species of P a p i l l a naturally i n f e c t e d with lungworm larvae i n Colorado. of i n f e c t e d s n a i l s .  Bighorn sheep are i n f e c t e d by accidental ingestion  Many Ashnola bighorn lambs are probably exposed to  i n f e c t i o n before leaving the winter range i n l a t e June or early July.  Snails  were not c o l l e c t e d on summer ranges, but l i k e l y e x i s t there. Lungs o f four bighorn sheep were examined during the study.  A l l had  small grey nodules up to one and one h a l f centimeters i n diameter on t h e i r diaphragmatic extremities. These nodules a l l contained adults, larvae, and eggs o f protostrongylin lungworms, probably P. s t i l e s i since they were located i n the parenchymal t i s s u e .  None of the lungs had more than ten  small lungworm nodules, and the maximum parasitized area was square centimeters.  about f i f t e e n  Examination of the bronchioles revealed no P. r u s h i .  The f a c t that such a large proportion of the Ashnola bighorn population  78 i s i n f e c t e d with lungworms suggests that lungworm disease may be an important population depressant.  Under conditions of stress from long periods of i n -  clement weather and poor n u t r i t i o n verminous pneumonia and secondary bacteri a l invasion of the lungs could cause widespread m o r t a l i t y .  This pattern  of m o r t a l i t y appears to n a t u r a l l y regulate populations of bighorn sheep i n the United States (Buechner op. c i t . ) . Known parasites of the Ashnola bighorn sheep herd are l i s t e d i n Table 21.  The winter t i c k and spinose ear t i c k have both been previously reported  from the C a l i f o r n i a bighorn i n B r i t i s h Columbia (Cowan,  195l)«  Sugden (op.  c i t . ) has also reported the paralysis t i c k , Dermacentor andersoni, from the Churn Creek herd.  This t i c k occurs commonly i n the Ashnola d i s t r i c t , but  was not found on either of two sheep c o l l e c t e d . Slope i n March 1961  A ewe c o l l e c t e d on South  had 58 spinose ear t i c k s i n one ear.  These were a l l  engorged, and together with t i c k feces, moulted skins, and ear secretions completely blocked the auditory canal, and must have made the ear rather i n e f f e c t u a l f o r hearing.  This t i c k i s known to cause large losses i n  domestic sheep herds i n the i n t e r i o r of B r i t i s h Columbia (G. J . Spencer, personal communication).  Numerous t i c k perforations were found i n the skin  of the body and neck of both sheep c o l l e c t e d . Cowan (op. c i t . ) has found the h a i r lungworm and stomach worm i n C a l i f o r n i a bighorn sheep at Vaseaux Lake, B r i t i s h Columbia.  The  thread-necked  worm, pinworm, and whipworm have been reported i n the Rocky Mountain b i g horn, but not i n the C a l i f o r n i a race. present study, however Cowan,  No tapeworms were found i n the  (1950-1955) found two bladderworms (Cysticer-  cus t e n u i c o l l i s ) i n a ewe examined i n the Ashnola i n  1951.  Parasites are widespread i n the Ashnola bighorn population, but at present are not s i g n i f i c a n t p a t h o l o g i c a l l y .  Although harbouring ear and  79  TABLE 21 PARASITES OF THE ASHNOLA HERD OF CALIFORNIA BIGHORN SHEEP  Parasite Dermacentor a l b i p i c t u s (winter t i c k ) Otobius megnini (Spinose ear t i c k ) Protostrongylus s t i l e s i ( h a i r lungworm) Nematodirus s p . ( t h r e a d - n e c k e d worm) Ostertagia sp. (stomach worm) Ski j abinema o v i s (pinworm) Trichurls ovis (Whipworm) Eimeria sp. _ (Coccidia) 1  Technique P. M.  E.  P. M.  E.  P. M. E. & Baermanization Baermanization & Z. S. F. P. M. E. P. M.  E.  P. M.  E.  Z. S.  F.  1 P o s t mortem e x a m i n a t i o n . ^Zinc sulphate c e n t r i f u g a l f l o t a t i o n . 3Appendi T a b l e s k and 6. X  Remarks C o l l e c t i o n s 1 and 2. Larvae and A d u l t s . Common. C o l l e c t i o n s 1 and 2. Heavy i n f e s t a t i o n . Ears o n l y . See t e x t d i s c u s s i o n , and T a b l e s 19 and 20. Only eggs and l a r v a e observed. C o l l e c t i o n s l c a r i d 2. Abundant i n abomasum. C o l l e c t i o n no. 1 o n l y . Caecum and l a r g e i n t e s t i n e . Abundant C o l l e c t i o n no. 2 o n l y . Abundant i n upper l a r g e i n t e s t i n e . S i n g l e oocyst observed. J  80  winter ticks, lungworms, stomachworms and pinworms, a ewe (bighorn collection number one) collected in March l$6l was in excellent condition with abundant fat on kidneys, mensenteries and heart. During severe winter conditions however, these latent infections can increase in virulence and contribute materially to mortality in the herd, Predation It must be stated at the outset that field observations during this study were not sufficient to permit adequate appraisal of predator prey relationships. It is difficult to objectively assess predation as a population limiting factor when only negative information i s available.  Negative  evidence however, at least suggests that predation on bighorn sheep i s not widespread in this region. According to Mr. A. West, chief predator control officer for the British Columbia Game Department (personal communication), there was no organized predator control in the Ashnola region previous to 1951* About 1950, coyote populations in the Okanagan-Similkameen region reached peak numbers. Coyote control measures were begun on Ashnola ranges in 1951 when several poison baits were set out. Coyotes have not been abundant in the area since. More poison baits were dropped from aircraft on the high mountain ranges in January, 1957. Although no more than twelve poison baits have been set out on Ashnola ranges since 1950 (A. West, personal communication) the few used were very efficient in lowering coyote numbers. Cougar control has largely been through hunting by game wardens. Adam Monks, formerly game warden in this region, estimates he has killed 70 cougars and Uo bobcats in the Ashnola from 19^0 until the present. He has hunted the area every winter since 19U0 and considers cougar numbers to be presently at a low level.  81  Predation can be detected ( 1 ) from k i l l s , ( 2 ) from observations of predators and prey i n contact, ( 3 ) from a consideration of vulnerable age classes and the likelihood, from mortality data, of the predator being responsible for the losses, and (k) from response of the herd to predator control. Only one freshly k i l l e d bighorn sheep was found during this study. On May 2 5 , I960, a ewe which had been dead about twelve hours was found at the forested margin of South Slope. at the scene. lactating. study.  Bear tracks and droppings were abundant  The ewe was ten year's old and was neither pregnant nor  This was the oldest of a l l ewe remains discovered during the  Cause of death was undoubtedly predation by a black bear.  The bear  returned for two successive nights to feed on the carcass. Bighorn sheep and predator species were observed i n close proximity on several occasions.  On three occasions coyotes were observed within 50  yards of sheep.  In a l l instances the two species showed only casual interest  i n one another.  On December 30, I 9 6 0 two coyotes which appeared to be  searching for pocket gophers came within 50 yards of a group of lit sheep, including several lambs.  The sheep were lying i n the snow on a relatively  flat area of South Slope, and even though the coyotes howled frequently, the sheep did not get up.  A few coyotes frequented the area during the  entire study period, and were observed on both summer and winter ranges. Fifteen observations of coyotes were made during the study. from one to four individuals.  These varied  There are an estimated 1 0 to 2 0 coyotes i n  the Ashnola region at the present time. Black bears and bighorn sheep were observed i n visual contact i n two instances.  Both of the bears were observed on South Slope i n May I 9 6 0 ,  when young lambs were numerous i n the v i c i n i t y .  On both occasions a l l sheep  82 within sight o f the bears f l e d to escape t e r r a i n . follow.  The bears d i d not  In one case the bear was alerted by human observers.  Since cougars and bobcats were not observed i t cannot be determined whether or not these species came i n contact with bighorn sheep.  Cougar  tracks on the winter ranges suggest that cougars and sheep do occasionally come i n contact. Several winter deer k i l l s found during the study were attributed to cougar predation. Wolves and g r i z z l y bears do not presently occur i n the Ashnola area and therefore do not come i n contact with bighorn sheep. Both bald and golden eagles showed an i n t e r e s t i n the sheep.  Bald  eagles were observed diving at ewe-lamb groups i n the lambing b l u f f s during May and June.  Golden eagles harassed ewe-lamb groups i n precipitous summer  range areas i n J u l y .  One golden eagle made several consecutive dives at a  ewe and lamb, while the lamb took refuge under i t s mother.  Since no physical  contact was observed I have no evidence of predation by eagles upon these sheep. Age structure data f o r t h i s herd shows a mortality pattern characteri z e d by high mortality i n the lamb and o l d age groups.  These can be con-  sidered the weakest groups i n the population. Epidemic d i e - o f f s , which often show no s e l e c t i o n f o r age, do not characterize C a l i f o r n i a bighorn populations.  KLein and Olson (i960) show that winter losses of deer from  starvation i n Alaska show a pattern of highest mortality i n the fawn and o l d age groups.  In the absence o f predation one would expect the mortality  to be d i s t r i b u t e d among the weak, namely the o l d , diseased, and the young. Murie 0-9kh) has found however, that even a strong predator l i k e the wolf, known to be preying extensively on D a l l sheep i n Alaska, preyed mainly on the weakest groups.  Murie also c i t e s evidence that coyotes and cougars  83 p r e y p r i m a r i l y on t h e weakest members o f deer p o p u l a t i o n s . o f p r e d a t i o n t h e r e f o r e , cannot be d e t e r m i n e d  The  significance  from t h e a v a i l a b l e m o r t a l i t y  data. Response o f t h e h e r d t o p r e d a t o r c o n t r o l i s d i f f i c u l t t o a s c e r t a i n because h e r d s i z e was began.  n o t a c c u r a t e l y known a t t h e t i m e p r e d a t o r  control  C e r t a i n l y t h e r e has been no marked i n c r e a s e i n h e r d numbers.since  c o y o t e c o n t r o l began i n 1951.  A l t h o u g h e v i d e n c e i s meagre, n a t u r a l p r e d a -  t i o n appears t o be r a t h e r i n e f f e c t i v e as a d e p r e s s a n t o f t h e A s h n o l a  bighorn  sheep p o p u l a t i o n .  Accidents A c c i d e n t a l deaths o c c u r i n most w i l d a n i m a l p o p u l a t i o n s . a u t h o r s have d e s c r i b e d a c c i d e n t s f a t a l t o b i g h o r n sheep. two sheep w i t h c r i p p l e d l i m b s were o b s e r v e d , 17, I 9 6 0 , was  a dead y e a r l i n g  i n t a c t and t h e r e was  sheep was depleted.  (23 months) was  and a y e a r l i n g .  study  On  The  April  carcass  The bone marrow o f t h i s  almost empty and f a t r e s e r v e s were  d e a t h from m a l n u t r i t i o n .  however r e v e a l e d a f r a c t u r e d l e f t humerus.  Closer  examination  T h i s d i s a b i l i t y p r o b a b l y weakened  t h e a n i m a l w h i c h f i n a l l y succumbed t o m a l n u t r i t i o n . a c c i d e n t a l d e a t h was  Daring t h i s  found on S o u t h S l o p e .  no e v i d e n c e o f p r e d a t i o n .  r e d c o l o u r e d , t h e stomach was This suggested  a ewe  Several  No o t h e r e v i d e n c e  of  found.  Hunting U n r e s t r i c t e d h u n t i n g i n t h e l a t e l 8 0 0 ' s was  one o f t h e p r i n c i p a l  d e c i m a t i n g f a c t o r s o f t h e A s h n o l a b i g h o r n sheep h e r d ( H i s t o r i c a l  Account).  As i t became r e c o g n i z e d however, t h a t b i g h o r n sheep o o u l d d i s a p p e a r t h e a r e a c o m p l e t e l y , l e g i s l a t i o n was  enacted t o r e s t r i c t h u n t i n g .  from Rigid  p r o t e c t i o n from h u n t i n g has been t h e m a j o r c o n s e r v a t i o n p r a c t i c e f o r t h i s herd.  This i s understandable  s i n c e h u n t i n g i s t h e most e a s i l y  controlled  84 of the factors potentially limiting a bighorn sheep population.  Such action  has a sound basis i n that hunting i n the early days was an important mort a l i t y factor.  Without such protection the population probably would have  entirely disappeared. Restriction of bighorn sheep hunting i n the Similkameen area began about 1887 when the season was closed from January 10 to September 10.  The  Ashnola herd was entirely closed to hunting from 1909 to 1946 and from 1948 to 1954 inclusive.  In November of 1947 a three-day open season was allowed.  From 1955 u n t i l the present, three-day open seasonsthave been permitted annually i n late September (except for a four-day season i n 1958).  The  bag limit has been one ram having at least a three-quarter horn curl.  The  regulation governing this restriction is called the "curl regulation".  It  i s intended to make the hunter more selective, to reduce the likelihood of ewes being k i l l e d i n mistake for young rams, and to preserve the esthetic value of trophy hunting.  Rams i n this herd normally reach three-quarter  curl horn size at five years of age, however some are legal size at four and one half years.  One eight-year old ram shot i n I960, because of the  shape of the horns, s t i l l had not reached three-quarter curl status. The net result of complete protection has not been more than a slight total herd increase, i f any.  Even though closed season enforcement was  probably inadequate i n early days, there is no evidence to suggest that i l l e g a l hunting alone has been limiting population increase since the inception of no-hunting legislation.  Therefore, i t must be concluded that  forces other than hunting are operating adversely on the Ashnola bighorn herd. In considering potential harvest size for the Ashnola herd, two conflicting objectives must be kept i n mind.  Must we harvest heavily to  85 p r e v e n t d r a s t i c m o r t a l i t i e s , o r can we superior trophies? to  The A s h n o l a h e r d i s s m a l l , r e l a t i v e l y s t a b l e and seems  be l i v i n g i n adjustment  numbers.  hunt o n l y o l d - a g e d rams which y i e l d  w i t h s e v e r e environmental c o n d i t i o n s t h a t  limit  L i m i t e d and h e a v i l y g r a z e d w i n t e r range p r o b a b l y r e t a r d s popu-  lation increase.  The environment  o f t h e h e r d i s n o t f a v o r a b l e toward i n r  c r e a s e t o h i g h d e n s i t y l e v e l s a t which the sheep a r e t h r e a t e n e d w i t h mass mortality.  Thus the A s h n o l a h e r d i s amenable t o the developement o f an  age s t r u c t u r e c h a r a c t e r i s t i c o f mature, s t a b l e p o p u l a t i o n s w i t h a l a r g e p r o p o r t i o n o f t r o p h y c l a s s rams. O u t s t a n d i n g t r o p h y rams among C a l i f o r n i a b i g h o r n sheep are n o t common. In  t h e A s h n o l a v e r y few rams have been n o t e d w i t h a f u l l horn curl,(360  degrees). or  I f a t r o p h y ram i s c o n s i d e r e d t o have a t h r e e - q u a r t e r c u r l  horn  g r e a t e r , animals o f a p p r o x i m a t e l y f i v e y e a r s o l d and o l d e r w i l l be  ded.  inclu-  F i v e and s i x - y e a r - o l d rams are n o t l a r g e t r o p h i e s , b u t are t r o p h i e s  nevertheless. As shown i n T a b l e 7,  about 37 p e r c e n t o f the A s h n o l a h e r d f a l l i n the  age group o f f i v e y e a r s and o l d e r . l a t i o n o f 250  Assuming an e q u a l sex r a t i o  and a popu-  sheep, about 45 rams w i l l be found i n t h i s age group.  This  agrees extremely w e l l w i t h numbers o f t h r e e - q u a r t e r c u r l rams observed ing of  the study.  I960, U l  Of 227  dur-  sheep c l a s s i f i e d w i t h o u t d u p l i c a t i o n i n t h e summer  were t h r e e - q u a r t e r c u r l rams.  T h i s i n no way  i m p l i e s however,  t h a t t h i s number o f rams can be h a r v e s t e d a n n u a l l y from t h e herd on a sustained y i e l d b a s i s . for.  Recruitment  t o the o l d e r age c l a s s e s must be  allowed  T a b l e 7 a l s o shows t h a t , a g a i n assuming an e q u a l sex r a t i o , about  rams w i l l be r e c r u i t e d i n t o t h e 5-year-and o l d e r age c l a s s each y e a r . is  10.6  p e r c e n t o f the male segment o f the p o p u l a t i o n .  t h e r e f o r e , t h a t n o t more t h a n 13  13 This  I t i s estimated  rams s h o u l d be h a r v e s t e d from the A s h n o l a  86 herd each year, providing herd size remains relatively constant. If rams of four years are also hunted, the allowable harvest could be increased slightly.  If open seasons were spaced at intervals of more than one year,  larger numbers could be harvested in a given season. Buechner (I960) estimates that not more than 1000 rams, or 12 to 14 percent of the ram segment of the bighorn sheep population.in the United States should be harvested each year. He bases this however, on age structure data for Dall sheep in Alaska, which have a larger percentage of animals in the old age groups than do Ashnola sheep. Thus recruitment is higher and a higher percentage can be harvested. Honess and Frost (1942) considered that no more than four rams or 6 percent of rams in the Gros Ventre bighorn herd in Wyoming should be harvested each year.. Data pertaining to the legal harvest of bighorn sheep in the Ashnola are presented in Table 22.  Over 90 percent of the sheep in Table 22 were  bagged east of the Ashnola River in the Observation-Joe Lake area. Since the inception of a regular season in 1955 the number of sheep hunters has steadily increased, being lh2 percent higher in i960 than in 19$$* Most of the increase has been due to an influx, in recent years, of hunters from outside of the Similkameen Valley. These hunters have also been taking a steadily increasing proportion of the animals harvested. Hunter success varied from 28.0 percent in 1958 to 6.7 percent in 1959,  and is  somewhat dependent on weather conditions. In 1959 for example, a heavy snowfall during the open season forced many hunters with horses to seek forage at lower elevations, and also greatly reduced visibility. The average number of rams bagged during the seven open seasons since 1947 is 9.0.  This is within the maximum estimate of 13 which can be safely  harvested on a sustained yield basis at the present population level. Table  87 22  a l s o shows a d e c r e a s i n g t r e n d i n t h e average  age o f rams k i l l e d .  i n d i c a t e s t h a t many o f the o l d e r i n d i v i d u a l s have now herd.  i960  In  rams t a k e n i n  t h e average  i960  age reached  a low o f  This  been removed from  $.1 y e a r s .  the  Three o f the  had s l i g h t l y l e s s t h a n t h r e e - q u a r t e r c u r l h o r n s .  In  each o f t h e s e b o r d e r l i n e cases t h e hunters i n v o l v e d were i n e x p e r i e n c e d i n sheep h u n t i n g .  T h i s problem i s l i k e l y t o worsen i n the f u t u r e w i t h i n c r e a s e d  numbers o f hunters F i g u r e 34  and d e c r e a s e d numbers o f o l d e r rams.  i l l u s t r a t e s t h e age d i s t r i b u t i o n o f kk  i n the A s h n o l a from killed.  through  i960.  rams k i l l e d  The t h r e e - y e a r - o l d ram was  illegally  I t i s noteworthy t h a t no rams over n i n e y e a r s o f age have been  harvested. i n the herd. o f age.  1955  o f t h e 54  Thus rams i n t h e s e o l d e r age c l a s s e s must be r a r e o r n o n - e x i s t e n t T h i s suggests t h a t - f e w rams n a t u r a l l y l i v e beyond n i n e y e a r s  L i f e table data substantiate t h i s observation.  The p r e s e n t r a t e o f h a r v e s t o f the A s h n o l a h e r d seems t o be c o n s e r v a t i v e , b u t s h o u l d not be g r e a t l y i n c r e a s e d .  F i e l d o b s e r v a t i o n s on the escapement  o f mature rams i n d i c a t e t h e y have n o t been o v e r h a r v e s t e d . open season was  i n i t i a t e d i n 1955  h e r d has been n o t e d . i n numbers.  no drop i n n u m e r i c a l s t a t u s o f the  Ashnola  I f any change has r e s u l t e d i t i s a s l i g h t i n c r e a s e  An unbalanced  h a r v e s t i n g rams o n l y .  S i n c e the r e g u l a r  sex r a t i o has not developed  Continued  as a r e s u l t o f  ram h u n t i n g c o u l d lower t h e male s i d e o f  t h e sex r a t i o and i n c r e a s e t h e n a t a l i t y r a t e o f t h e h e r d .  Controlled  r e d u c t i o n o f ram numbers can a l s o decrease i n t r a s p e c i f i c c o m p e t i t i o n f o r f o r a g e w i t h o u t i m p a i r i n g the r e p r o d u c t i v e r a t e o f t h e h e r d .  Therefore,  h u n t i n g s h o u l d be an i m p o r t a n t f e a t u r e o f t h e program f o r c o n s e r v a t i o n o f t h i s b i g h o r n sheep h e r d . I l l e g a l k i l l i n g o f A s h n o l a sheep has not been p r e v a l e n t d u r i n g r e c e n t years.  L i m i t e d escape r o u t e s  ( o n l y one r o a d e n t e r s the area) and  frequent  88  TABLE 22 LEGAL CALIFORNIA BIGHORN HARVEST IN ASHNOLA REGION, 1 9 4 7 - 1 9 6 0 .  Year 1947 : :i'9'55 1956 1957 1958 1959 I960  Total  Number Number of of Rams Killed Hunters  35 UO 51 50 6o 85  9 8 5 13 Hi 4 10  63  Average Age of Rams Killed  7.0  5.4 6.7 6.5 6.8 5.1  1  Residence of Successful Hunters Similkameen Other than Similkameen Valley  8 5 5 7 1 4  8 7 3 6  30  24  0 0  Data from Taylor, E. W., Unpublished report, B. C. Game Branch.  CO  < or  o  en  UJ CQ  2  5  6  7  ESTIMATED  FIGURE  3 4 .  HARVESTED I960,  AGE IN  SUBJECT  AGE  DISTRIBUTION THE TO  ASHNOLA T H E  8  OF  9  10  I I  12  (YEARS)  44  REGION  BIGHORN FROM  THREE-QUARTER  RAMS 1955 T H R O U G H  CURL  REGULATION.  89  patrols by enforcement officers discourage poaching.  Cattle herders in  the area have reported finding carcases of several illegal sheep. These animals were likely shot during the hunting season through ignorance or carelessness, then left on the range. I have also found several sheep skeletons near trails and in other positions suggesting they had not died a natural death. Two such skeletons were of sheep killed within the last two years, and in both cases no limb bones could be found.. This suggests that the animals were poached, probably by deer hunters, and the choicest meat was taken. Such poaching is not common however, and illegal hunting cannot be considered a major cause of mortality in the Ashnola herd.. BEHAVIOR Migration and Movements Topographical characteristics, featuring pronounced relief, reduce the necessity of long seasonal migrations for the Ashnola bighorn sheep herd. A l l sheep in the area occupy separate summer and winter ranges, but in some cases there is no distinct division between the two. Bighorn sheep exhibit considerable variation in migratory habit. Murie (1944)  has noted that Dall sheep are migratory in Alaska. Smith (1954)  and Couey (195>0) describe similar seasonal movements of the Rocky Mountain bighorn in Idaho and Montana respectively. Honess and Frost (1942) state that "Seasonal migrations of bighorn sheep are almost non-existent in the present day herds of Wyoming." Green (1949) states that among bighorn sheep herds in Banff National Park, Alberta, there are "no well defined seasonal movements to and from winter and summer ranges."  Sugden (1961)  describes both migratory and non-migratory herds of California bighorn sheep in the Chilcotin region of British Columbia. A herd with no available alpine range spent the entire year within a few square miles.  90  As classified by Urquhart  (1958), Ashnola  bighorn sheep undertake a  seasonal or annual remigration, since they return to the same range each year and the migration is closely related to the changing seasons. This seasonal remigration has an altitudinal basis. Arrows in Figure 19 show the  chief migratory routes of the Ashnola herd. Rams leave the winter ranges before the ewe-lamb-yearling groups.  Their spring migration is a gradual drift upward and away from the winter range. Rams start moving into the subalpine zone in late May or early June, depending on time of snow melt. They proceed into the alpine zone by late June, following the growth of new spring forage on south facing mountain slopes. At this time large snow drifts are s t i l l present on northerly exposed mountainsides. Smith  (1954) found  that Rocky Mountain bighorn  rams in Idaho had usually disappeared entirely from the winter range by the middle of May.  Despite higher elevation of the Idaho ranges, the ram  migration is earlier there than in the Ashnola. The spring migration of matriarchal groups is more a true migration than that of the rams, and occurs at a later date. At lambing time (May) considerable snow is s t i l l present on the alpine ranges, therefore lambing takes place on the winter range. Ewe groups do not usually migrate until early July. Their migration i s a distinct exodus rather than the gradual drift characteristic of the rams. Rocky Mountain bighorns studied by Couey  (1950)  in Montana however, migrated from the winter range in late  April and in May, previous to lambing. The Crater Mountain summer and winter ranges are relatively contiguous, and sheep here only migrate from 2 to h miles. The alpine range of Crater Mountain is occupied by both ram and ewe groups until mid-summer at which time the rams usually move elsewhere. East of the Ashnola River a differ-  91 e n t i a l m i g r a t i o n o f t h e sexes t a k e s p l a c e .  The O b s e r v a t i o n - J o e Lake range  i s used almost e x c l u s i v e l y by rams, and the Haystack Lakes range  ( F i g u r e 19)  s t u d y o n l y one  by ewe-lamb-yearling  ewe group was  ram group i n t h e l a t t e r .  Mountain-Cathedral  groups.  During the e n t i r e  o b s e r v e d i n the former a r e a , and o n l y one  M°Cann (1956) a l s o noted t h a t ewe  i n the G-ros V e n t r e h e r d o f Wyoming remained  and ram bands  e n t i r e l y s e p a r a t e d by o c c u p y i n g  d i f f e r e n t areas o f t h e h i g h summer r a n g e . Assuming t h a t a l p i n e - s u b a l p i n e areas are d e s i r a b l e as summer range f o r t h e herd, i t seems l o g i c a l t h a t t h e rams, w h i c h are n o t h e l d to the w i n t e r range by lambing, range.  s h o u l d seek t h e n e a r e s t and most a c c e s s i b l e summer  A l t h o u g h t h e y m i g r a t e an average o f f o u r t o s i x m i l e s , t h e i r summer  and w i n t e r ranges are r e l a t i v e l y contiguous«(Figure 1 9 ) . That t h e ewe  groups m i g r a t e s i x t o t e n m i l e s a c r o s s an u n s u i t a b l e ,  timbered, i n t e r m e d i a t e range, when a l p i n e areas e x i s t w i t h i n two m i l e s o f South S l o p e , r e q u i r e s a d i f f e r e n t e x p l a n a t i o n however.  This migration also  i n v o l v e s c r o s s i n g t h e South Fork o f t h e A s h n o l a R i v e r .  Differences i n  topography o f t h e ram is  and ewe  summer ranges suggest t h a t p r o t e c t i o n o f lambs  a s i g n i f i c a n t f a c t o r i n summer range s e l e c t i o n by ewe  groups.  The  area  o c c u p i e d by t h e rams i s l a r g e l y one o f r o l l i n g mountains w h i l e the a r e a chosen by the ewes i s much more p r e c i p i t o u s i n n a t u r e , and o f g e n e r a l l y higher elevation Williams  ( F i g u r e 35)•  T h i s i s c o n t r a r y to the s u g g e s t i o n o f  (1925) t h a t areas f r e q u e n t e d by b i g h o r n rams "are g e n e r a l l y o f  h i g h e r a l t i t u d e and o f a more rugged  c h a r a c t e r t h a n those t h a t t h e ewes  frequent." P o s t r u t h a b i t a t s e l e c t i o n a l s o suggests a d i f f e r e n c e i n the t a n c e o f escape t e r r a i n t o ewe  and ram g r o u p s .  impor-  Most ewe-lamb groups  r e a d y access t o escape t e r r a i n throughout t h e w i n t e r .  had  No ewe-lamb groups  FIGURE 35* Foreground shows alpine range used b y ram groups i n vicinity of Joe Lake. Mountains i n background provide summer range for most ewe-lamb groups east of t h e Ashnola River. The latter area i s more precipitous than the ram range.  92 were o b s e r v e d n o r t h o f the p o l e b r i d g e ( m i l e s i x on t h e A s h n o l a Road), Ram  groups however were commonly o b s e r v e d on t h e lower A s h n o l a R i v e r ranges  i n c l o s e p r o x i m i t y "bo the A s h n o l a Road. Creek r a n g e . the  Only ram groups i n h a b i t e d t h e P a u l  Rams on t h e s e s l o p e s c o u l d see and hear p a s s i n g t r a f f i c on  S o u t h e r n T r a n s p r o v i n c i a l Highway as w e l l as o c c a s i o n a l v e h i c l e s on a  farm r o a d a l o n g t h e lower edge o f the s l o p e i t s e l f .  Ram  groups seem more  t o l e r a n t toward c e r t a i n a s p e c t s o f c i v i l i z a t i o n t h a n are ewe  groups.  The p r o g r e s s i v e m i g r a t i o n o f sheep from South S l o p e i n t h e s p r i n g o f 1 9 6 0 i s shown i n T a b l e 2 3 • 1961  Fewer rams u s e d South S l o p e i n the s p r i n g o f  however, when most rams moved from the lower A s h n o l a and S t a r v a t i o n -  F l a t i r o n ranges to the s u b a l p i n e  gone v i a  on South S l o p e f o r most o f t h e w i n t e r .  Juniper Slope.  A few rams remained  Ewe-lamb-yearling groups o f 32  and  4 5 animals were o b s e r v e d on a l p i n e range a t about 8 0 0 0 f e e t i n e l e v a t i o n near C a t h e d r a l Lakes on J u l y 9 and J u l y 12 r e s p e c t i v e l y . be found i n t h e  area  on J u l y 7 and 8 .  No sheep  could  Thus the ewe groups m i g r a t e d almost  e n t i r e l y w i t h i n a two o r t h r e e day p e r i o d .  F i r s t sheep seen on the C r a t e r  Mountain a l p i n e a r e a were a ewe group o f 4 l , and a ram group o f 1 2 , 8.  T h e r e f o r e ewe  the  same t i m e .  on J u l y  groups e a s t and west o f the A s h n o l a R i v e r m i g r a t e d about  The f a l l m i g r a t i o n t a k e s p l a c e l a r g e l y from mid-to l a t e October, w i t h ewe groups mostly p r e c e d i n g t h e rams. on South S l o p e i n t h e f a l l was October 1 0 .  In i 9 6 0 the f i r s t  a group of 1 9 ewes, lambs and y e a r l i n g s  A l l were f a t and i n e x c e l l e n t c o n d i t i o n .  South S l o p e i n t h e f a l l ,  sheep group observed  a l o n e i n d i v i d u a l , was  The f i r s t ram  seen on October 2 3 .  t h i s time over f o r t y ewes and lambs were on the s l o p e .  on  on At  Most of the rams  r e t u r n e d about October 30. A l t h o u g h m i g r a t i o n s o f montane mammals are common, t h e f a c t o r s m o t i v -  93 ating such movements are not fully understood.  That sheep must leave the  montane summer ranges i n the f a l l i s obvious at such latitude as that of British Columbia.  However i t is the spring migration, which sheep are not  compelled to make, which needs explanation.  Presumably the ultimate factor  involved is survival value, otherwise natural selection would eliminate such a habit. TABLE 23 SPRING MIGRATION OF SHEEP FROM SOUTH SLOPE  Numbers of sheep remaining on South Slope MAY 28 29 Ewe groups Ram groups  30 8 12 13  1  1*2  60 l U 17 15  5  JUNE 15 16  17  24 30  10k 100 90 0 10 0  13* 6*  99 0  0  JULY 6 10 11 14  60 40 0  0  9 0  0  •0  Includes ewes, lambs, yearlings, and occasional young rams.  Juniper Slope.  The actual stimulus to spring migration may involve several factors. Plants on the winter range usually remain succulent u n t i l late June or early July, however the rams start their d r i f t back to summer pastures before tills time.  Rams may however, be seeking vegetation i n i t s most nutritional  early growth stages, and follow new growth upward. By the time the ewelamb groups leave the winter range, temperatures are high and herbaceous growth is maturing and drying out.  These factors probably stimulate the  sheep to migrate to the alpine ranges, which they have learned from past experience yield succulent forage i n mid-summer.  Annoying insects were  as abundant on summer ranges as on winter ranges and are not thought to be an important stimulus to spring migration.  Forage quality, warm temperatures  9k  and acrophilia (a love for high places) probably a l l stimulate spring migration. Snowstorms i n the alpine-subalpine zone of the Ashnola commonly occur as early as late August.  Such snowstorms however are ephemeral i n nature,  and do not force the sheep back to the winter range.  In l°6o,return of  the sheep to the winter range corresponded with the arrival of permanent snow i n the alpine-subalpine zone.  As breeding does not take place u n t i l  the sheep return to the winter range, the f a l l migration could be partly motivated by a reproductive urge, particularly i n the case of the rams. The f a l l migration is most l i k e l y a result of a combination of the gametic, alimental, and climatic incentives of Heape (1931)* No rams were observed on the winter ranges i n July, August, or September.  From early July u n t i l early October only one matriarchal group  was seen on the winter range.  This group of 12 ewes, lambs and yearlings  fed for several days i n August on green growth around two springs on South Slope, then disappeared again.  Smith (1954) observed a few mountain sheep  in Idaho on low winter ranges throughout the summer.  These were mostly  ewe groups. Two significant non-migratory changes i n sheep distribution occur i n the Ashnola herd.  About mid-August the rams, and to a lesser extent ewe  groups also, descend from open alpine slopes into the subalpine zone, largely on northerly exposed slopes.  The latter areas present more succu-  lent forage i n late summer and f a l l .  By following new spring growth  altitudinally and then moving on to alpine-subalpine northerly exposed slopes i n late summer, the sheep are able to eat vernal vegetation over a six month period. After the breeding season, during which most of the sheep are concen-  95 t r a t e d on t h e l a r g e r ranges sucb^as S o u t h S l o p e , t h e r e i s a l s o a d i s p e r s a l o f ram groups t o t h e F l a t i r o n and l o w e r A s h n o l a R i v e r r a n g e s . t h e s e rams go as f a r as P a u l C r e e k .  Some o f  No ewe groups were o b s e r v e d on t h e  l a t t e r ranges d u r i n g t h e w i n t e r .  Grouping and S o c i a l  Dynamics  The b i g h o r n sheep i s one o f t h e most s o c i a l o f b i g game s p e c i e s .  The  number o f b i g h o r n sheep c o m p r i s i n g each o f t h e h90 o b s e r v a t i o n s made between. May 1,  i960 and A p r i l 30, 1961 v a r i e d from s o l i t a r y a n i m a l s up t o groups  o f 55 sheep. animals.  Average group s i z e b a s e d on t h e above o b s e r v a t i o n s was 9*3  O n l y unalarmed groups have been r e c o r d e d . On a r e a s o f r e l a t i v e  sheep abundance s u c h as S o u t h S l o p e , alarmed sheep groups t e n d t o band t o g e t h e r , and as many as I4O have been counted i n one group a f t e r t h e o b s e r v e r w a l k e d a c r o s s t h e m i d d l e o f t h e s l o p e i n p l a i n v i e w o f t h e sheep. The A s h n o l a h e r d , d u r i n g b o t h summer and w i n t e r was s p l i t i n t o v a r i o u s s m a l l e r bands.  I n some cases t h e s e were s e p a r a t e d b y as much as t e n t o  fifteen miles. On a r e a s o f r e l a t i v e p o p u l a t i o n c o n c e n t r a t i o n s u c h as S o u t h S l o p e t h e r e a r e , i n a sense, no d e f i n i t e h e r d s .  F l u c t u a t i o n s i n group c o m p o s i t i o n  are  f r e q u e n t o n s u c h a r e a s as groups s p l i t and r e j o i n , e s p e c i a l l y d u r i n g  the  rutting period.  A t o t h e r seasons numerous c o m b i n a t i o n s o f sexes and  ages f o r m r e l a t i v e l y s t a b l e g r o u p s .  Some ram groups on s m a l l d i s j u n c t  range u n i t s remained c o n s t a n t i n s i z e f o r one t o two months d u r i n g t h e winter. Observed sheep groups were c l a s s i f i e d i n t o t h r e e t y p e s a c c o r d i n g t o t h e i r composition — c o n t a i n e d males o n l y .  ram g r o u p s , ewe groups and m i x e d g r o u p s .  Ram groups  Ewe groups u s u a l l y c o n t a i n e d ewes, y e a r l i n g s , lambs  96  and immature rams (two and three years o l d ) .  No rams over three years of  age were observed with ewe groups on the summer range. age or older were considered mature.  Rams four years of  Mixed groups were any groups contain-  ing both mature ewes (two years of age and older) and mature rams.  The  nature o f the mixed groups i s e s s e n t i a l l y matriarchal, nevertheless they were c l a s s i f i e d separately. Figure 3 6 shows the v a r i a t i o n i n group s i z e of Ashnola bighorn sheep by months. mics.  Male, female and mixed groups vary considerably i n t h e i r dyna-  Female groups are l a r g e s t i n June immediately after lambing.  This  i s attributed to the highly s o c i a l nature of the lambs, which appeared to exhibit more a f f i n i t y f o r one another than f o r t h e i r mothers.  Gregariousness  i n these groups remained high on the summer range but dropped greatly during the r u t . After the rut, female group s i z e remained r e l a t i v e l y constant -. u n t i l lambing.  The May and June figures f o r female groups may both be  biased s l i g h t l y since during lambing many lone ewes are i n rough country and more d i f f i c u l t to observe than the larger groups on the open slopes. Mean size o f female groups f o r the entire year was 1 0 . 7 animals.  Female  groups ranged i n s i z e from single i n d i v i d u a l s to groups of over I4O.  The  largest group observed contained 5 5 i n d i v i d u a l s . Male groups are largest i n the spring and smallest from October to December.  In many cases however, not enough groups were observed to y i e l d  r e l i a b l e means.  Male groups during the rutting period consisted mostly of  one or two individuals t r a v e l l i n g between ewe groups.  Yearlings were not  seen with ram groups, and two-year-old rams were only occasionally with them.  Ram groups on the summer range were considerably smaller than ewe  groups.  Mean s i z e of ram groups f o r the entire year was 6 . 1 animals, also  smaller than f o r female groups.  Ram groups of 1 5 or more i n d i v i d u a l s were  often observed i n the spring and the largest ram group seen contained 2 2 ,  2  z  2]  9 s o §  3)  o  CD C  m OJ  ^  *  o o •n z AV. NO. A N I M A L S  ~  33-  cn U~)  m >  " I  5 I  PER  GROUP  yi  1  ro o  1  f~  X  K  J>  2  2  cn O cn <-  5> co ±  J  ;o  o c  co  > r-  o  70  CM  O c  ro  TJ CO  TO  -JO 2  o c  ro  a> j>  J> >  c/>  c  GROUP  _  C  ro O  CD 3D O  PER  CD -  O I I> CD  m  ANIMALS  _  5  cn ,  !M c  O 2 >  AV. NO.  Si  oi U1  CD  ro  CD CD > £ CD 33 CD  S  F  _ 30 CD 2 CT)  ro O  • £  m m •xj  a>  o 2  cn  x  2 O  co  J>  2 CD  ro O  m  cn  ro  -c  CM CD  <5 cn o  (0 = ro oi in ° O O o c. MIXED G R P S AS A P E R C E N T O F TOTAL GRFS  m % m  70 o c TJ CO  97 most o f which were f o u r y e a r s o f age o r o l d e r .  Jones  (1950)  found rams  most commonly i n groups o f two o r t h r e e , and saw none l a r g e r t h a n t w e l v e . His  o b s e r v a t i o n s however were c o n f i n e d t o the summer and f a l l  seasons.  S i g n i f i c a n t numbers o f mixed groups were o b s e r v e d o n l y from October u n t i l February.  T h i s agrees w i t h o b s e r v a t i o n s f o r the C a l i f o r n i a b i g h o r n  and Rocky Mountain b i g h o r n b y Jones who  (op. c i t . )  and M Cann c  (1956)  found t h a t male and female groups mixed o n l y d u r i n g t h e r u t .  mixed group i n the f a l l was n o t o b s e r v e d u n t i l October 25.  .Mixed  respectively The f i r s t groups  as a p e r c e n t a g e o f t o t a l groups observed, r e a c h a peak i n November c o r r e l a t e d w i t h t h e peak o f r u t t i n g a c t i v i t y  ( F i g u r e 36).  The f r e q u e n c y o f  o c c u r r e n c e o f mixed groups d i d n o t drop as q u i c k l y a f t e r t h e r u t t i n g as i t r o s e b e f o r e t h e r u t t i n g p e r i o d , i n d i c a t i n g a l i n g e r i n g between rams and ewes. the  M Cann (op. c i t . )  a s s o c i a t i o n w i t h the'female g r o u p s .  period  attraction  a l s o n o t e d t h a t a few rams p r o l o n g Mixed groups o b s e r v e d i n the  A s h n o l a were much l a r g e r t h a n unmixed groups d u r i n g t h e same month.  No  mixed groups were o b s e r v e d from June t h r o u g h September, t h e p e r i o d when most o f t h e sheep were o n t h e i r summer r a n g e s . from October t h r o u g h F e b r u a r y was 12.6  Average s i z e o f mixed  groups  sheep.  During May, when many o f t h e ewes had l e f t the open s l o p e s f o r more p r o t e c t i v e lambing t e r r a i n , a few sheep groups were encountered which c o u l d o n l y be c l a s s i f i e d as immature. y e a r l i n g s , t w o - y e a r - o l d sheep, o r b o t h .  Such groups c o n s i s t e d e i t h e r o f These groups were n o t as wary as  ewe groups, c o u l d be approached q u i t e c l o s e l y , and seemed t o l a c k a l e a d e r . Such groups were a s s i m i l a t e d by ewe-lamb groups as the l a t t e r appeared on the  open s l o p e s .  The s i z e o f t h e s e groups averaged about f i v e  individuals  each. S e v e r a l authors suggest i n c r e a s e d g r e g a r i o u s n e s s o f sheep d u r i n g t h e breeding season.  I n the A s h n o l a h e r d some l a r g e groups were seen d u r i n g  98 t h i s p e r i o d , but many s m a l l e r groups c o n s i d e r a b l y weight the average downward. Frequency d i s t r i b u t i o n s o f group s i z e s by three-month p e r i o d s presented i n Figure 3 7 .  The  frequency  d i s t r i b u t i o n s o f ram,  ewe,  are and mixed  groups v a r y c o n s i d e r a b l y w i t h time, b e i n g most d i s s i m i l a r d u r i n g t h e i n g season (October  through December).  Ram  and ewe  groups had  breed-  a very  s i m i l a r s i z e d i s t r i b u t i o n i n the s p r i n g .  R u t t i n g and Lambing The peak o f t h e r u t i n t h e A s h n o l a ber i n i 9 6 0 .  The  South S l o p e .  Four rams were o b s e r v e d  February 6 ,  1961.  f i r s t ram  The  ewe  from mid-to l a t e Novemseen October 23  i n r u t t i n g c o n d i t i o n was chasing' a ewe  on S o u t h S l o p e  on  on  appeared to be i n e s t r u s , and the chase went on  i n t e r m i t t e n t l y f o r about an h o u r . group d i s a p p e a r e d  herd occured  C o p u l a t i o n was  from s i g h t s e v e r a l t i m e s .  not observed,  T h i s was  the l a s t  however t h e observation  o f s e x u a l a c t i v i t y among the sheep, b u t i n d i c a t e s t h a t t h e r u t t i n g p e r i o d i s r a t h e r extended. Young rams ( t h r e e - y e a r - o l d and younger) u s u a l l y d i s p l a y e d o n l y c a s u a l s e x u a l i n t e r e s t i n the ewes. t o c o p u l a t e w i t h a ewe ram.  One  w h i c h had  t h r e e - y e a r - o l d ram  however was  j u s t been mounted f i v e times by an o l d e r  I n g e n e r a l , s e x u a l a c t i v i t y was  much more subdued than t h a t d e s c r i b e d  f o r the Rocky Mountain b i g h o r n by Spencer ( 1 9 4 3 ) and M i l l s number o f rams p u r s u i n g five.  ewes i n e s t r u s was  precipitous areas.  (1937).  The  u s u a l l y not more t h a n f o u r o r  Headlong p u r s u i t o f ewes over rugged t e r r a i n was  r a t h e r than t h e r u l e .  observed  the  exception  U s u a l l y t h e groups r a n r a t h e r s l o w l y and  avoided  O f t e n t h e r e c e p t i v e ewes r a n o n l y a few y a r d s  before  b e i n g mounted. J o u s t i n g o f rams was  commonly observed  but t h i s a l s o l a c k e d t h e v i o l e n c e  99 d e s c r i b e d by many o b s e r v e r s . (op.  cit.)  No  " b a t t l e s r o y a l " , mentioned by  were observed among rams i n the A s h n o l a .  Spencer  S e r i o u s ram  bouts  were n o t o b s e r v e d a f t e r e a r l y December, a l t h o u g h p l a y f u l b u t t i n g was v e d throughout t h e y e a r . cal  No evidence was  They  were  report.  The ewes had s i x  During t h i s time a mature ram t r i e d t o mount one o f the ewes. broken o f f about f o u r i n c h e s from the  The f i r s t lambs seen i n  of  two  encounters d u r i n g a twenty minute p e r i o d , each w i t h a l o u d  h o r n o f one ewe was  on May  6, i960,  Both had lambs w i t h them, and were  a group o f twelve sheep c o n t a i n i n g t h r e e a d u l t rams.  head-to-head  ing  On December  o b s e r v e d from $0 y a r d s w i t h ten-power  b i n o c u l a r s so were n o t m i s i d e n t i f i e d . in  noted o f i n j u r y o r s e r i o u s p h y s i -  d e p l e t i o n as a r e s u l t o f b r e e d i n g a c t i v i t y .  ewes were seen j o u s t i n g .  obser-  2 respectively.  i960  and  1961  A  skull.  were f o u r on May  7  and t h r e e  These were on South S l o p e a t t h e edge o f the lamb-  b l u f f s and appeared t o be a t l e a s t one week o l d . lambs o b s e r v e d on South S l o p e i n  i960  and  1961.  T a b l e 2h shows numbers  The numbers p r o b a b l y  do n o t c o r r e s p o n d e x a c t l y w i t h lambing i n t e n s i t y , s i n c e most o f the ewes and lambs d i d n o t come o u t o f t h e lambing b l u f f s u n t i l the lambs were a week o r more o l d .  There i s a l s o t h e p o s s i b i l i t y o f an i n f l u x o f ewes and  lambs from o t h e r r a n g e s .  The lambing p e r i o d extends from l a t e A p r i l  l a t e June w i t h a peak i n l a t e May. range was  One  until  s m a l l lamb o b s e r v e d on the summer  probably born i n J u l y .  Lambing ranges i n the A s h n o l a a l l embody s i m i l a r c h a r a c t e r i s t i c s . are  p r e c i p i t o u s and l i b e r a l l y c o v e r e d w i t h c l i f f s  (Figure  38).  Most are between 3000 and  £000  and r o c k o u t c r o p p i n g s  f e e t i n e l e v a t i o n and the  warmer and d r i e r s o u t h e r l y exposures are chosen.  Most o f the lambing  l i e a d j a c e n t t o g r a s s l a n d s l o p e s used as s p r i n g range. forested  (Figure  39).  They  bluffs  Some a r e p a r t l y  FIGURE 3 8 . A small ewe-lamb group i n escape t e r r a i n at the west end o f South Slope. Bluebunch wheatgrass and squaw current are the commonest plants i n these b l u f f s .  FIGURE 39. Lambing and escape t e r r a i n on the south side o f Crater Mountain. Few forage species grow i n these b l u f f s but adequate spring range l i e s nearby (Figure 1 7 ) . West Fork o f the Ashnola River i s i n the background.  100 TABLE 2k SPRING LAMB COUNTS FOR SOUTH SLOPE  Number o f Lambs Observed on South S l o p e  2 7 I960  3  1961  k  10  May 17  19  6  5  6  5  23 25  1  June  8 13  15 17  12 16 20 31 35 22  5 16  A l t h o u g h ewes w i t h v e r y young lambs were seen i n t h e lambing b l u f f s , no ewes were seen a c t u a l l y g i v i n g  birth.  For t h e f i r s t few weeks  after  lambing t h e ewe-lamb groups u s e d o n l y a f r i n g e o f t h e s p r i n g range a d j a c e n t t o t h e lambing b l u f f s .  O f t e n t h e y would o n l y v e n t u r e a few y a r d s from  s u c h escape t e r r a i n and h a s t i l y f l e e f o r cover a t t h e s l i g h t e s t  disturbance.  T h i s b e h a v i o r p a t t e r n was p a r t i c u l a r l y e v i d e n t on C r a t e r Mountain, and hampered e f f o r t s t o o b t a i n an a c c u r a t e lamb count. Throughout t h e s t u d y i t has been n o t e d t h a t adequate escape t e r r a i n is  a prime r e q u i s i t e  groups.  i n sheep h a b i t a t s e l e c t i o n ,  p a r t i c u l a r l y o f ewe-lamb  T h i s f a c t o r i s b e l i e v e d i n p a r t r e s p o n s i b l e f o r lower sheep  numbers on C r a t e r Mountain t h a n i n t h e South S l o p e a r e a . t a i n adequate s p r i n g range i s p r e s e n t a d j a c e n t to s u i t a b l e  On C r a t e r Mounescape t e r r a i n ,  however t h i s range i s r e l a t i v e l y f l a t , h e a v i l y g r a z e d by c a t t l e , and supp o r t s v e r y l i t t l e bunchgrass. u n a v a i l a b l e during the w i n t e r .  Because o f snow cover t h i s range i s l a r g e l y The s t e e p , bunchgrass covered, s o u t h e r l y  exposed w i n t e r i n g s l o p e s on C r a t e r however, a r e surrounded o n l y b y Douglas f i r f o r e s t , o f l i t t l e v a l u e as escape t e r r a i n .  On South S l o p e , good s p r i n g  and w i n t e r range l i e s a d j a c e n t t o escape t e r r a i n .  Adequate y e a r - r o u n d  escape t e r r a i n , as w e l l as adequate w i n t e r g r a z i n g areas, must n o t be  101 overlooked as a.factor i n the selection o f s i t e s for the introduction of bighorn sheep herds. The f i r s t lambs observed i n 1961 food.  (May 2) were already eating plant  Lambs also nursed commonly at t h i s time.  As the lambs grew older  both frequency and duration o f nursing periods decreased.  Lambs were never  observed to nurse f o r over 2$ seconds, and usually the period was much shorter.  As noted by Smith (1954) the feeding period was always terminated  by movement of the ewe; the lambs never stopped suckling v o l u n t a r i l y .  The  l a s t observation of successful nursing i n I960 was made on October 10, however an attempted nursing was observed on December 6.  Lambs i n the Ashnola  appear to be weaned by the time they are f i v e or s i x months o l d . MANAGEMENT The primary concern of management f o r both sporting and esthetic purposes should continue to be the perpetuation of the C a l i f o r n i a bighorn as a member o f B r i t i s h Columbia's game fauna.  The presence o f the C a l i -  f o r n i a bighorn i n huntable numbers i n B r i t i s h Columbia contributes to the d i s t i n c t i o n the province enjoys from i t s unexcelled v a r i e t y o f big game species.  To ensure the ultimate conservation of the race however, the  usual objective o f producing a huntable population may subordinated to other considerations.  at times have to be  With the r a p i d l y growing  appreciation  of the outdoors i t i s becoming increasingly important that t h i s b i g game species be managed i n such a way as to render the greatest possible sporting and esthetic returns. Aldo Leopold (1933) wrote, "Continuous census i s the yardstick of success or f a i l u r e i n conservation." Censusing however i s one o f the most expensive and time consuming a c t i v i t i e s required f o r the proper management of bighorn sheep populations. Compared to many bighorn herds the  1 0 2  Ashnola herd i s r e l a t i v e l y a c c e s s i b l e , t h e r e f o r e r e g u l a r censusing should n o t be i m p r a c t i c a b l e . S m a l l s i z e o f the A s h n o l a h e r d makes i t i m p e r a t i v e t h a t any downward t r e n d i n numbers be immediately  recognized.  The b e s t counts can u s u a l l y be o b t a i n e d w h i l e animals a r e c o n c e n t r a t e d on w i n t e r ranges d u r i n g l a t e w i n t e r and e a r l y s p r i n g .  Snow depths  are n o t  u s u a l l y s u f f i c i e n t a t t h i s time t o p r e v e n t f o o t t r a v e l on t h e w i n t e r ranges, and snowshoes are n o t r e q u i r e d . p r a c t i c a b l e i n most y e a r s .  From A p r i l to June horseback  counts  are  Maneuverable, slow speed a i r c r a f t have proved  to be o f v a l u e i n d e t e r m i n i n g d i s t r i b u t i o n and numbers i n the h e r d d u r i n g mid-winter  when f o o t t r a v e l i s most d i f f i c u l t .  I t i s recommended t h a t  a i r count and one ground count o f t h e A s h n o l a h e r d be made y e a r l y . a i r c r a f t census  s h o u l d be made i n January o r F e b r u a r y .  one  The  Since the present  A s h n o l a sheep p o p u l a t i o n s i z e i s known w i t h some a c c u r a c y and a comparable s e r i e s o f a e r i a l counts have been made s i n c e 1 9 5 5  (Table 2), t r e n d f i g u r e s  c o u l d be o b t a i n e d b y c o u n t i n g sheep on South S l o p e o n l y .  Past  aerial  censuses suggest t h a t counts on South S l o p e a r e l e s s v a r i a b l e than f o r the e n t i r e A s h n o l a r e g i o n .  South S l o p e i s l a r g e and m o s t l y v o i d o f  t r e e s and sheep on i t can be counted of time.  counts  a c c u r a t e l y from the a i r i n a minimum  Y e a r l y ground counts t o o b t a i n i n f o r m a t i o n on lamb p r o d u c t i o n  and s u r v i v a l s h o u l d be made i n mid-June, a f t e r lambing and b e f o r e m i g r a t i o n o f ewe-lamb groups t o t h e summer r a n g e .  Such c l a s s i f i e d counts s h o u l d  i n c l u d e South S l o p e and C r a t e r Mountain i f the t o t a l lamb crop i s t o be determined. fied.  I f o n l y r a t i o s a r e r e q u i r e d , the e n t i r e herd need n o t be  classi-  South S l o p e i s t h e most r e l i a b l e ground t r e n d count a r e a o f t h e  Ashnola.  S p r i n g ground surveys w i l l a l s o y i e l d i n f o r m a t i o n on range  winter k i l l s ,  use,  p r e d a t o r l o s s e s and g e n e r a l c o n d i t i o n o f b i g game.  I t i s e s s e n t i a l t h a t censuses be made a t t h e same time each y e a r .  All  103 counts s h o u l d a l s o be conducted weather c o n d i t i o n s i f p o s s i b l e . observers take p a r t . counts  and censuses  a t t h e same time o f day and under s i m i l a r I t i s d e s i r a b l e t h a t only experienced  The a c c u r a c y o f t h e above methods o f conducting t r e n d cannot be a c c e p t e d w i t h o u t q u e s t i o n .  I b e l i e v e how-  ever, t h a t p a s t r e s u l t s speak w e l l f o r t h e c o n t i n u e d u s e and improvement o f s u c h methods. When d e v e l o p i n g a management program f o r t h e p r o t e c t i o n o f a s c a r c e animal such as t h e C a l i f o r n i a b i g h o r n , t h e most apparent  starting pointi s  t o recommend t h e e l i m i n a t i o n o f a l l p o s s i b l e sources o f l o s s .  Closed  seasons  and p r e d a t o r c o n t r o l a r e u s u a l l y t h e f i r s t measures t o be p u t i n t o e f f e c t . Game l a w enforcement i s b e l i e v e d t o be adequate i n t h i s a r e a a t p r e s e n t . P r e d a t i o n i s p o p u l a r l y accepted as an i m p o r t a n t m o r t a l i t y f a c t o r among t h e Ashnola bighorn herd.  A c t u a l l y t h e l o s s from t h i s s o u r c e appears  t o be  r a t h e r s m a l l , though i t does e x i s t and must r e c e i v e c o n s i d e r a t i o n i n management p l a n n i n g . F i e l d o b s e r v a t i o n s d u r i n g t h i s s t u d y were n o t s u f f i c i e n t t o p e r m i t adequate a p p r a i s a l o f p r e d a t o r - p r e y r e l a t i o n s h i p s .  No evidence was uncovered  however, t o i n d i c a t e t h a t i t would be a d v i s a b l e t o i n a u g u r a t e an i n t e n s i v e c o n t r o l program f o r any p r e d a t o r on t h e A s h n o l a r a n g e s .  Moderate c o n t r o l  o f s p e c i f i c p r e d a t o r s however, may become n e c e s s a r y a t c e r t a i n  times.  Continued h a r v e s t i n g o f t h e h e r d as p a r t o f i t s management program s h o u l d be c o n t i n u e d f o r reasons d i s c u s s e d p r e v i o u s l y .  N a t u r a l l o s s e s may  be a b s o r b i n g a s m a l l p o p u l a t i o n s u r p l u s w h i c h can b e t t e r be t a k e n b y t h e hunter.  S p e c i e s competing w i t h b i g h o r n sheep f o r range u s e a r e n o t l i k e l y  t o d i m i n i s h g r e a t l y i n numbers w i t h i n t h e near f u t u r e , t h e r e f o r e t h e Ashn o l a b i g h o r n h e r d w i l l p r o b a b l y remain r e l a t i v e l y c o n s t a n t i n s i z e , h a r v e s t w i l l remain s m a l l .  and t h e  Among game s p e c i e s , t o p p r i o r i t y s h o u l d be g i v e n b i g h o r n sheep on key areas o f p r o d u c t i o n .  Such p r i o r i t y a r i s e s from t h e p r e s e n t  their  scarcity  o f the C a l i f o r n i a b i g h o r n and t h e i r d e s i r a b i l i t y from b o t h m a t e r i a l and recreational standpoints.  Such p r i o r i t y does not mean e l i m i n a t i o n o f o t h e r  b i g game s p e c i e s , b u t i t does mean r e d u c i n g deer numbers as low as p o s s i b l e through  encouraged and d i r e c t e d h u n t i n g p r e s s u r e .  H a r v e s t i n g ewes a t t h i s  time would have no b e n e f i c i a l e f f e c t s on h e r d p r o d u c t i v i t y , and t h e r e f o r e s h o u l d n o t be attempted.  I f i t i s d e s i r a b l e to reduce range u t i l i z a t i o n  by r e d u c i n g animal numbers, t h e n t h e f i r s t attempt s h o u l d be t o reduce the numbers o f s p e c i e s competing w i t h t h e sheep. t h e range as a game a r e a , i t may c a t t l e numbers.  B a r r i n g complete purchase o f  n o t be p o s s i b l e to s i g n i f i c a n t l y reduce  Deer p o p u l a t i o n s i n B r i t i s h Columbia however a r e i n a f a r  l e s s p r e c a r i o u s p o s i t i o n than those o f the C a l i f o r n i a b i g h o r n , and  could  be l i b e r a l l y h a r v e s t e d i n the A s h n o l a r e g i o n w i t h no danger o f p o p u l a t i o n annihilation. H a r v e s t i n g o n l y mature rams i s n o t e f f i c i e n t management s i n c e t r o p h y animals r e q u i r e more y e a r s u t i l i z i n g f o r a g e and space b e f o r e t h e y can harvested,  and fewer animals  e n t e r t h e h a r v e s t s i n c e more n a t u r a l l o s s e s  t a k e p l a c e over a l o n g e r time p e r i o d .  I f q u a l i t y has p r i o r i t y over q u a n t i t y  however, t h e t h r e e - q u a r t e r c u r l r e g u l a t i o n has Ashnola  area.  Very few i l l e g a l animals  I t i s extremely i m p o r t a n t fall,  s e r v e d i t s purpose i n the  have been k i l l e d .  t h a t t h e open season be s e t e a r l y i n t h e  as has been the p r a c t i s e i n p a s t y e a r s , when t h e rams are  from t h e ewes and j u v e n i l e s .  be  Hunting  segregated  l a t e r than mid-October, when the sheep  have banded t o g e t h e r on the w i n t e r ranges, would i n c r e a s e the  likelihood  o f ewes and young b e i n g k i l l e d and i n t e r f e r e w i t h c o u r t s h i p and  breeding  activities.  likelihood  T h i s might be dangerous t o herd p r o d u c t i v i t y .  The  io5 o f o v e r h a r v e s t i n g would a l s o i n c r e a s e w i t h a l a t e r season,  s i n c e the rams  would be more c o n c e n t r a t e d and a c c e s s i b l e , t h e r e f o r e e a s i e r t o secures As was  n o t e d i n the s e c t i o n on h u n t i n g , t h e number o f sheep hunters  i n the A s h n o l a a r e a has been s t e a d i l y i n c r e a s i n g s i n c e  1955*  With i n c r e a s e d  h u n t i n g p r e s s u r e , harassment by h u n t e r s might be more i m p o r t a n t i n l o w e r i n g hunter s u c c e s s t h a n s c a r c i t y o f t r o p h y rams. i n T a b l e 23, s i n c e i n 1959 (60 and 85  T h i s i s suggested by the d a t a  and I960, t h e y e a r s o f g r e a t e s t h u n t e r numbers,  r e s p e c t i v e l y ) s u c c e s s r a t i o s were the l o w e s t s i n c e the  has been open (6.7 p e r c e n t and 11.8  percent r e s p e c t i v e l y ) .  season  I f hunter  numbers c o n t i n u e t o r i s e i n t h e f u t u r e a system o f p e r m i t h u n t i n g  should  be e s t a b l i s h e d . The number o f p e r m i t s allowed must take i n t o account some measure o f c r i p p l i n g l o s s and hunter s u c c e s s . the open season  c o u l d be l e n g t h e n e d  With a p e r m i t h u n t i n g system  and hunter success would p r o b a b l y i n -  crease m a r k e d l y . A c h e c k i n g s t a t i o n has been o p e r a t e d on the A s h n o l a Road each open season s i n c e 1955.  The  continued o p e r a t i o n of t h i s s t a t i o n i s e s s e n t i a l  i f the annual h a r v e s t o f rams i s to be a c c u r a t e l y determined, open season  adjustments  made.  and subsequent  I t i s e s s e n t i a l too, t h a t the o b j e c t i v e s o f  a management p l a n f o r a r a c e as s c a r c e as the C a l i f o r n i a b i g h o r n p r o v i d e f o r the c o n t i n u i n g c o l l e c t i o n and i n t e r p r e t a t i o n o f b a s i c d a t a .  Weights  and measurements o f sheep, p a t h o l o g i c a l m a t e r i a l s and hunter s u c c e s s can a l l be c o l l e c t e d r e a d i l y a t a checking s t a t i o n .  data  Hunter and F i l l m o r e  (1954) have g a t h e r e d c o n s i d e r a b l e d a t a on lungworm i n f e s t a t i o n i n Colorado b i g h o r n sheep herds by examining hunters.  sheep l u n g s c o l l e c t e d from s u c c e s s f u l  Such d a t a c o u l d a l s o be c o l l e c t e d from b i g h o r n herds i n B r i t i s h  Columbia i f hunters were a d e q u a t e l y i n f o r m e d . employing  The g r e a t e s t advantage i n  the h u n t i n g season as an o p p o r t u n i t y f o r o b t a i n i n g study m a t e r i a l  106 l i e s i n t h e r e l a t i v e l y l a r g e sample which can be o b t a i n e d i n a s h o r t time from w i d e l y d i s t r i b u t e d a r e a s .  The t a k i n g o f l a r g e samples by o t h e r means  might arouse p u b l i c a n i m o s i t y .  The major disadvantage i s t h a t a d d i t i o n a l  c o n t r o l o f hunters i s n e c e s s a r y , the hunting  and t h i s i n c r e a s e s t h e c o s t o f o p e r a t i n g  season.  The most i m p o r t a n t phase o f management.of t h e A s h n o l a b i g h o r n herd s h o u l d be t h e p r e s e r v a t i o n o f w i l d e r n e s s h a b i t a t i n i t s n a t u r a l s t a t e . Man's e x p l o i t a t i o n o f remaining w i l d e r n e s s t r a c t s w i l l d i m i n i s h B r i t i s h Columbia's c a p a c i t y t o produce mountain sheep.  U n l i k e many herds o f t h e  Rocky Mountain b i g h o r n , t h e C a l i f o r n i a b i g h o r n s occupy g r a s s l a n d s w i t h i n t h e major g r a z i n g zone o f B r i t i s h Columbia.  Thus management o f t h e h a b i t a t  i n v o l v e s , i n many cases, c a r e f u l m u l t i p l e use o f t h e r a n g e s . G r a z i n g by domestic  stock, a t present c a t t l e , i s the primary l a n d use  that threatens the welfare o f the Ashnola bighorn herd.  A l r e a d y l a r g e areas  o f sheep w i n t e r range have r e v e r t e d c o n s i d e r a b l y from t h e c l i m a x c o n d i t i o n and d e c l i n e d markedly i n f o r a g e p r o d u c t i o n .  A p o l i c y o f u n d e r s t a n d i n g and  c o o p e r a t i o n between t h e game management agency, g r a z i n g a d m i n i s t r a t o r and range p e r m i t e e i s n o t ali-Jays s u f f i c i e n t t o m a i n t a i n b i g h o r n numbers, even i f g r a z i n g p r a c t i c e s a r e good.  I n c r e a s e d s t o c k i n g demands by c a t t l e m e n a r e  out o f p r o p o r t i o n t o range improvements. c l u s i v e u s e o f c r i t i c a l w i n t e r ranges  I t would be d e s i r a b l e t o g i v e ex-  such as South S l o p e t o b i g h o r n sheep.  T h i s can n o t be done however, w i t h o u t j e o p a r d i z i n g t h e o p e r a t i o n s o f t h e c a t t l e grazing permitee.  Thus t h e o n l y way t o ensure c o n t r o l over t h e  f u t u r e o f t h i s sheep h e r d i s t o buy o u t t h e e n t i r e h o l d i n g s o f a l l permitees g r a z i n g c a t t l e on sheep w i n t e r r a n g e s . operation i s involved.  I n t h i s case o n l y one r a n c h i n g  P a r t o f t h e purchase  s a l e o f t h e home r a n c h and c u l t i v a t e d  areas.  p r i c e c o u l d be r e c o v e r e d by  107 P r o t e c t i o n o f b i g h o r n sheep ranges from e x c e s s i v e and  influences  domestic g r a z i n g must become a major phase o f t h e management o f t h i s  herd. no  human  A l l o t h e r management c o n s i d e r a t i o n s  a r e secondary t o t h i s one, f o r  amount o f p r o t e c t i o n o f t h e h e r d w i l l i n c r e a s e  habitat i s not a v a i l a b l e .  sheep numbers i f s u i t a b l e  108 DISCUSSION A d i s c u s s i o n now  seems p e r t i n e n t t o i n t e g r a t e and e v a l u a t e f a c t o r s  a f f e c t i n g p o p u l a t i o n s t a t u s o f the Ashnola herd.  Historically, l i t t l e i s  known o f e a r l y sheep numbers i n t h e Similkameen r e g i o n .  Several references  suggest t h a t sheep were more abundant on A s h n o l a ranges i n the l a t e l800's than t h e y are t o d a y .  However s i n c e t h e s e o b s e r v a t i o n s were n o t i n a l l  cases made by t r a i n e d o b s e r v e r s t h e y cannot be accepted w i t h o u t  reservation.  E a r l y counts by Game Department p e r s o n n e l , a l t h o u g h s u b j e c t t o c o n s i d e r a b l e v a r i a t i o n , seem t o be t h e most r e l i a b l e census f i g u r e s a v a i l a b l e . i n d i c a t e t h a t the A s h n o l a h e r d has f l u c t u a t e d l i t t l e t i o n from h u n t i n g began i n  1909*  They  i n size since protec-  I t f o l l o w s t h a t i f a d e c l i n e i n the  A s h n o l a herd took p l a c e , i t o c c u r r e d b e f o r e 1909* A l t h o u g h i t cannot be s t a t e d w i t h c e r t a i n t y t h a t the A s h n o l a h e r d d e c l i n e d g r e a t l y i n e a r l y days, i t i s known t h a t sheep i n the Similkameen r e g i o n became much r e s t r i c t e d i n t h e i r d i s t r i b u t i o n i n t h e e a r l y 1900*s, u n t i l t h e A s h n o l a herd was  t h e o n l y remnant.  The o n l y abnormal a c t i v i t y  on t h e s e f o r m e r l y o c c u p i e d ranges between t h e time o f human s e t t l e m e n t o f t h e Similkameen V a l l e y and t h e time t h e sheep d i s a p p e a r e d , were sheep h u n t i n g and domestic s t o c k g r a z i n g . to  domestic  S i n c e much o f the range i s i n a c c e s s i b l e  s t o c k i t seems l i k e l y t h a t h u n t i n g was  an important  factor  c o n t r i b u t i n g t o t h e e a r l y d e c l i n e o f sheep i n t h e Similkameen r e g i o n . t o r i c a l r e f e r e n c e s a l s o i n d i c a t e t h a t h u n t i n g p r e s s u r e on A s h n o l a was  heavy i n the l a t e l 8 0 0 ' s .  s e v e r a l hunts to  His-  ranges  This information i s believed r e l i a b l e since  are w e l l documented.  U n r e s t r i c t e d h u n t i n g then, i s thought  have been an i m p o r t a n t d e c i m a t i n g f a c t o r o f Similkameen sheep herds i n  e a r l y days.  The l o s s o f emergency w i n t e r ranges because o f s e t t l e m e n t o f  t h e Similkameen V a l l e y p r o b a b l y a l s o c o n t r i b u t e d t o range r e s t r i c t i o n s i n  109 the area. The  e v a l u a t i o n o f the f a c t o r s l i m i t i n g herd i n c r e a s e at present  be based on more c o n c r e t e d a t a .  The p o p u l a t i o n was  a n a l y s e d from  age r a t i o s and age s t r u c t u r e d a t a from sheep remains. of  the herd i n  observed  The n a t a l i t y r a t e  I960, based on known lamb p r o d u c t i o n , was 18 p e r c e n t .  m o r t a l i t y r a t e was of  can  c a l c u l a t e d from l i f e t a b l e d a t a by d i v i d i n g t h e  the column o f t h e number o f i n d i v i d u a l s dying i n each age c l a s s ,  A  total (d^-),  by t h e t o t a l o f t h e column o f i n d i v i d u a l s a l i v e i n each age c l a s s , ( l x ) , and m u l t i p l y i n g the q u o t i e n t by 100.  T h i s i s b e l i e v e d t o be t h e most  r e l i a b l e method f o r c a l c u l a t i n g t h e mean annual m o r t a l i t y r a t e s i n c e each d  x  v a l u e c o n t r i b u t e s i t s p r o p e r weight to t h e mean r a t e .  Averaging  the  age s p e c i f i c m o r t a l i t y r a t e s y i e l d s a m o r t a l i t y r a t e w h i c h i s much too h i g h s i n c e age  c l a s s e s w i t h few i n d i v i d u a l s b u t h i g h m o r t a l i t y r a t e s c o n t r i b u t e  t h e most weight.  The m o r t a l i t y r a t e o f l6,$  l i f e t a b l e d a t a , does not seem u n r e a s o n a b l e .  p e r c e n t , c a l c u l a t e d from  The s i m i l a r i t y o f t h i s r a t e  and t h e above n a t a l i t y r a t e suggests h e r d s t a b i l i t y . for  the  t h e h e r d agree w i t h t h e above o b s e r v a t i o n .  The  Recent census d a t a c h i e f o b j e c t i o n t o the  v a l i d i t y o f assuming h e r d s t a b i l i t y , l i e s i n t h e d i f f e r e n t time p e r i o d s r e p r e s e n t e d by t h e n a t a l i t y and m o r t a l i t y d a t a .  The n a t a l i t y d a t a r e p r e s e n t  I960 o n l y , w h i l e t h e m o r t a l i t y d a t a r e p r e s e n t s e v e r a l y e a r s p r e v i o u s t o 196l.  I t i s not l i k e l y t h a t t h e n a t a l i t y r a t e would v a r y markedly from  y e a r t o y e a r , however m o r t a l i t y r a t e s are known t o v a r y c o n s i d e r a b l y . T h e r e f o r e comparing the  i960 n a t a l i t y r a t e w i t h a m o r t a l i t y r a t e averaged  o v e r s e v e r a l y e a r s i s p r o b a b l y more r e l i a b l e than comparing i t w i t h the m o r t a l i t y r a t e o f t h e y e a r i n q u e s t i o n , which i s o f course not known. A l t h o u g h t h e i n i t i a l post-lambing  lamb-to-ewe r a t i o s r e c o r d e d f o r  i960 and 196l a r e h i g h , t h e y can be e n t i r e l y accounted f o r on t h e b a s i s o f  110 s i n g l e b i r t h s t o ewes o f t h r e e y e a r s o f age o r o l d e r *  There i s o n l y v e r y  l i m i t e d evidence o f t w i n b i r t h s and b r e e d i n g o f y e a r l i n g ewes i n t h e herd, a l t h o u g h p r e v a l e n c e o f t h e l a t t e r i s d i f f i c u l t t o determine.  High  initial  p r o d u c t i v i t y p o i n t s to m o r t a l i t y a t some o t h e r time o f t h e y e a r , s i n c e deaths must o c c u r i f the p o p u l a t i o n remains s t a b l e .  The l a r g e s t number o f  remains i n any age group o f the l i f e t a b l e d a t a are i n t h e aero t o one group.  A l l sheep d y i n g i n t h i s group were n i n e t o twelve months o f  year  age,  i n d i c a t i n g t h a t heavy m o r t a l i t y o c c u r s i n t h e lamb group l a t e i n t h e i r f i r s t winter.  Only two  o f the $1  sheep remains found were on summer r a n g e s .  Even though the w i n t e r ranges were s e a r c h e d more t h o r o u g h l y t h a n were the summer ranges, former  such a d i s p r o p o r t i o n a t e amount o f m a t e r i a l found on the  cannot be a t t r i b u t e d merely  to s e a r c h i n g e r r o r .  i t y i n t h e A s h n o l a h e r d then, o c c u r s on w i n t e r r a n g e s . t h a t t h e s e ranges  are i n some way  Most o f the m o r t a l This indicates  l i m i t i n g population increase.  S t a b i l i t y o f the A s h n o l a p o p u l a t i o n must be maintained  either  by  m o r t a l i t y w i t h i n the a r e a o c c u p i e d by the herd, by d i s p e r s a l from t h e a r e a , or  by b o t h o f t h e s e f a c t o r s a c t i n g s i m u l t a n e o u s l y .  d i s p e r s a l has been f o u n d . to  L i t t l e evidence f o r  S u i t a b l e , and f o r m e r l y o c c u p i e d , ranges p e r i p h e r a l  the A s h n o l a a r e a have never been r e p o p u l a t e d by b i g h o r n sheep.  f a c t t h a t l o n e sheep may  The  wander i n t o areas o f u n s u i t a b l e h a b i t a t and d i e  t h e r e cannot be o v e r l o o k e d .  C o n s i d e r i n g , however, t h e h i g h l y s o c i a l  o f b i g h o r n sheep and t h e i r tendency  t o occupy t r a d i t i o n a l ranges  t e r r a i n , l i t t l e l o s s seems a t t r i b u t a b l e t o t h i s f a c t o r . b i g h o r n herd i s not l o s i n g members by d i s p e r s a l ,  I f the  nature  and escape Ashnola  and i t s n a t a l i t y r a t e i s  s u f f i c i e n t f o r r a p i d p o p u l a t i o n i n c r e a s e , one can o n l y conclude t h a t one or more m o r t a l i t y f a c t o r s must be o p e r a t i n g t o l i m i t t h i s i n c r e a s e . L i t t l e evidence o f p r e d a t i o n on b i g h o r n sheep was  found d u r i n g t h i s  Ill study.  The most s u g g e s t i v e evidence t h a t p r e d a t i o n i s not a s i g n i f i c a n t  p o p u l a t i o n d e p r e s s a n t , i s l a c k o f p o p u l a t i o n response l a r g e l y coyote c o n t r o l .  The  i s n o t adequately known. increase at present.  to predator  control,  e f f e c t i v e n e s s o f t h e c o n t r o l measures however,  Hunting  does not appear to be l i m i t i n g  S i n c e t h e r e g u l a r open season was  herd  19$$,  initiated i n  no s i g n i f i c a n t change i n n u m e r i c a l s t a t u s o f t h e herd has been noted.  The  few mature rams taken y e a r l y would not l i k e l y i m p a i r the r e p r o d u c t i v e r a t e o f the h e r d .  T h e r e f o r e i t must be concluded  t h a t f o r c e s other than  hunting  are o p e r a t i n g a d v e r s e l y on t h e p o p u l a t i o n . The importance o f d i s e a s e and p a r a s i t i s m as m o r t a l i t y f a c t o r s A s h n o l a ranges i s d i f f i c u l t to determine.  Normally  on  h e a l t h y sheep were  found i n f e c t e d w i t h b o t h i n t e r n a l and e x t e r n a l p a r a s i t e s w i t h o u t n o t i c e a b l e harmo  No deaths as a d i r e c t r e s u l t o f p a r a s i t i s m o r d i s e a s e were  during the study.  The  observed  f a c t t h a t 88 p e r c e n t o f the a d u l t p o p u l a t i o n i s  i n f e c t e d w i t h lungworms however, suggests  t h a t lungworm d i s e a s e may  i n d i r e c t cause o f m o r t a l i t y i n the weaker age c l a s s e s .  be  an  Under c o n d i t i o n s  o f s t r e s s from l o n g p e r i o d s o f i n c l e m e n t weather and poor n u t r i t i o n , v e r minous pneumonia and o t h e r p a r a s i t i c i n f e c t i o n s p r o b a b l y c o n t r i b u t e to m o r t a l i t y , the b a s i c cause o f w h i c h i s most l i k e l y f o o d  shortage.  S i n c e i n s u f f i c i e n t f o o d has been found to l i m i t many p o p u l a t i o n s o f montane ivngulates, i t was  c o n s i d e r e d n e c e s s a r y to study f o o d r e l a t i o n s h i p s  o f t h e h e r d i n more d e t a i l t h a n o t h e r p o t e n t i a l l i m i t i n g f a c t o r s . b y c a t t l e i s t h e p r i m a r y l a n d use t h r e a t e n i n g the w e l f a r e o f t h e herd at present.  Grazing Ashnola  Range c o m p e t i t i o n between b i g h o r n sheep and c a t t l e b a s i -  c a l l y i n v o l v e s s p r i n g and f a l l u t i l i z a t i o n by c a t t l e o f sheep w i n t e r - s p r i n g ranges.  The  c o m p e t i t i v e i n t e r a c t i o n was  e x t e n t t o which t h e two  e v a l u a t e d by d e t e r m i n i n g  the  s p e c i e s g r a z e t h e same areas, t h e e x t e n t to which  112 t h e y p r e f e r t h e same f o r a g e s p e c i e s , and the s u p p l y o f p r e f e r r e d f o r a g e i n r e l a t i o n t o t h e number o f g r a z i n g  animals.  Data p r e s e n t e d i n an e a r l i e r s e c t i o n showed t h a t on t y p i c a l w i n t e r range u n i t s c a t t l e used l a r g e l y slopes.  t h e f l a t areas w h i l e sheep p r e f e r e d s t e e p e r  Forage p r e f e r e n c e s on areas grazed i n common were s i m i l a r w i t h  exception.  Sheep a t e an average  o f 35 p e r c e n t p a s t u r e sage i n w i n t e r w h i l e  c a t t l e d i d not u t i l i z e t h i s s p e c i e s . grazing i n  one  U t i l i z a t i o n measurements a f t e r  cattle  i960 showed t h a t o n l y 20 p e r c e n t o f South S l o p e was grazed t o  p r o p e r use o r beyond.  A f t e r combined summer c a t t l e use and w i n t e r b i g h o r n  sheep use, o n l y 25 p e r c e n t o f the s l o p e was  grazed s i m i l a r l y .  D e s p i t e the  s i m i l a r i t y o f f o o d h a b i t s , d a t a f o r areas g r a z e d and degree o f u t i l i z a t i o n show t h a t c o m p e t i t i o n on South S l o p e between c a t t l e and b i g h o r n sheep f o r t h e f o r a g e crop o f  i960 was  slight.  E x c l o s u r e p l o t d a t a show t h a t , a l t h o u g h f o r a g e c o m p e t i t i o n was on sheep w i n t e r ranges,  c o n s i d e r a b l e f o r a g e was  removed by c a t t l e .  slight On  the  a r e a sampled by t h e t e n animal e x c l o s u r e p l o t s e r e c t e d on r e p r e s e n t a t i v e sheep w i n t e r i n g a r e a s , 3k p e r c e n t by weight o f t h e d r y matter p r e s e n t consumed by c a t t l e .  However, no o v e r w i n t e r m o r t a l i t y which c o u l d be  b u t e d t o m a l n u t r i t i o n was  d e t e c t e d on South S l o p e f o r the w i n t e r o f  was attri-  1960-61.  I t i s concluded t h e r e f o r e t h a t s u f f i c i e n t f o r a g e remained t o c a r r y the p r e s e n t sheep p o p u l a t i o n t h r o u g h t h e w i n t e r . ever, was  much m i l d e r t h a n  I f South S l o p e was  The w i n t e r o f 1960-61 how-  average.  g r a e d by c a t t l e i n t h e f a l l as w e l l as s  early  summer, as has u s u a l l y been t h e p r a c t i s e i n p a s t y e a r s , c a t t l e would p r o b a b l y s t a r t u t i l i z i n g t h e s t e e p e r s l o p e s and t h e a r e a g r a z e d beyond proper u s e would i n c r e a s e markedly. f o r a g e was  The  f a c t t h a t 3k p e r c e n t o f t h e  available  removed by c a t t l e i n o n l y t h r e e weeks o f g r a z i n g , supports  this  113 assumption.  I f adverse snow c o n d i t i o n s accompanied s u c h g r a z i n g p r a c t i s e s  c o m p e t i t i o n would be even more pronounced. food shortage r e s u l t i n g  I t i s t h e r e f o r e suggested t h a t  from a combination o f heavy summer g r a z i n g by  c a t t l e and o c c a s i o n a l u n a v a i l a b i l i t y  o f f o r a g e i n w i n t e r because  c o n d i t i o n s i s the most p r o b a b l e f a c t o r  o f snow  l i m i t i n g p o p u l a t i o n i n c r e a s e on  South S l o p e and i n t h e A s h n o l a d i s t r i c t i n g e n e r a l .  T h i s i s s u p p o r t e d by  t h e o c c u r r e n c e , i n some y e a r s , o f heavy m o r t a l i t y i n the lamb group  late  i n t h e i r f i r s t w i n t e r and by the f a c t t h a t n e a r l y a l l sheep remains were found on t h e w i n t e r r a n g e s .  Ill* SUMMARY 1.  2.  A f i e l d s t u d y o f t h e A s h n o l a b i g h o r n sheep h e r d was c a r r i e d o u t from May  i960  cal  d a t a on which t o base management and c o n s e r v a t i o n p r a c t i c e s .  t h r o u g h June  1961.  The o b j e c t i v e was t o g a t h e r sound e c o l o g i -  The h e r d p r e s e n t l y c o n t a i n s about 250 sheep and has remained r e l a t i v e l y c o n s t a n t s i n c e t h e e a r l y 1900's.  3.  T y p i c a l w i n t e r ranges of  s o u t h e r l y exposure,  o f t h e h e r d a r e edaphic c l i m a x g r a s s l a n d s l o p e s between  2500  and  c l i m a x dominant i s n o r m a l l y bluebunch little ho  feet i n elevation.  wheatgrass.  The  F o r e s t e d range i s  used.  Summer range o f t h e h e r d i s i n t h e a l p i n e and s u b a l p i n e zones,  6000 5.  6000  to  8500  from  feet i n elevation.  L i n e p o i n t t r a n s e c t s o f 500 p o i n t s each showed t h a t areas grazed b y sheep o r sheep and deer o n l y , showed l i t t l e o r no s u c c e s s i o n a l degene r a t i o n from t h e climax, w h i l e areas g r a z e d r e g u l a r l y b y c a t t l e showed pronounced  6.  degeneration.  Lamb-to-ewe r a t i o s were h i g h i n t h e s p r i n g o f  i960  and  t w i n n i n g , and b r e e d i n g o f y e a r l i n g ewes a r e n o t thought n i f i c a n t occurrence.  1961,  but  t o be o f s i g -  Y e a r l i n g - t o - e v e r a t i o s were low i n i960 and  high i n 1961. 7o  A life death.  t a b l e was c o n s t r u c t e d from 57 sheep remains o f known age a t A l l b u t two o f t h e remains were found on w i n t e r ranges.  The  m o r t a l i t y p a t t e r n i s c h a r a c t e r i z e d b y h i g h lamb m o r t a l i t y l a t e i n t h e f i r s t w i n t e r , fewer deaths i n t h e age group between one and s i x y e a r s of  8.  age and h i g h e r m o r t a l i t y i n t h e o l d e r age groups.  The n a t a l i t y r a t e o f t h e h e r d was r a t e based on l i f e f i g u r e s suggests  18  p e r c e n t i n i960, and t h e m o r t a l i t y  t a b l e data i s 16.5 percent.  herd  stability.  The s i m i l a r i t y o f t h e s e  9.  About 70 p e r c e n t o f t h e sheep w i n t e r range and 20 p e r c e n t o f t h e sheep summer range i s used b y c a t t l e .  10.  Chip and p e l l e t counts on l i n e p l o t t r a n s e c t s on South S l o p e , t h e most i m p o r t a n t w i n t e r range,  showed t h a t 60 p e r c e n t o f c a t t l e u s e  and 9 p e r c e n t o f sheep u s e was on areas o f l e s s than 15 (16 11.  degree s l o p e  percent o f the area).  Grazed  stem counts showed t h a t 65 p e r c e n t o f f o r a g e eaten by sheep  was a l s o eaten b y c a t t l e .  P a s t u r e sage made up 35 p e r c e n t o f t h e  w i n t e r sheep d i e t b u t was n o t eaten b y c a t t l e . 12.  Utilization,  as based on s t u b b l e h e i g h t , showed t h a t 20 p e r c e n t o f  South S l o p e was g r a z e d beyond p r o p e r u s e a f t e r c a t t l e g r a z i n g i n i960, and 25 p e r c e n t was g r a z e d beyond p r o p e r u s e a f t e r sheep g r a z i n g t h e following winter.  Thus areas grazed b y sheep and c a t t l e were l a r g e l y  d i f f e r e n t and c o m p e t i t i o n was s l i g h t . 13«  E x c l o s u r e p l o t t e c h n i q u e showed t h a t c a t t l e u t i l i z e d 34 p e r c e n t b y w e i g h t o f t h e f o r a g e a v a i l a b l e on r e p r e s e n t a t i v e b i g h o r n w i n t e r - s p r i n g ranges i n i960. Food s h o r t a g e r e s u l t i n g from a combination  o f heavy summer g r a z i n g b y  c a t t l e and o c c a s i o n a l u n a v a i l a b i l i t y o f f o r a g e i n w i n t e r because o f snow c o n d i t i o n s i s suggested as t h e f a c t o r l i m i t i n g h e r d i n c r e a s e . l5«  Because o f l a r g e l y d i f f e r e n t h a b i t a l s e l e c t i o n and f o r a g e h a b i t s , c o m p e t i t i o n between mule deer and b i g h o r n sheep i s v e r y l i m i t e d .  16.  Baermanization  o f f r e s h f e c a l m a t e r i a l showed 88 p e r c e n t o f t h e herd,  e x c l u s i v e o f lambs, t o be i n f e c t e d w i t h p r o t o s t r o n g y l i n lungworms. There was no s i g n i f i c a n t d i f f e r e n c e i n t h e i n f e c t i o n r a t e o f y e a r l i n g , ewe o r ram groups, b u t fewer lambs were i n f e c t e d .  L a r v a l output was  lower i n lamb and y e a r l i n g samples than i n t h o s e o f a d u l t s .  17«>  B a e r m a n i z a t i o n d a t a suggest a s e a s o n a l v a r i a t i o n i n p r o t o s t r o n g y l i n l a r v a output, most l a r v a e b e i n g p a s s e d from December t o February, fewest from March t o  18.  and  May.  S n a i l s known t o be i n t e r m e d i a t e h o s t s f o r p r o t o s t r o n g y l i n lungworms i n o t h e r areas were found on A s h n o l a ranges.  19o  P o s t mortem examination o f two two  20.  s p e c i e s o f t i c k s , lungworms, stomachworms, pinworms and whipworms.  P r e d a t i o n does not appear t o be l i m i t i n g h e r d i n c r e a s e . certainly identifiable black bear  21.  sheep c o l l e c t e d d u r i n g t h e s t u d y r e v e a l e d  About hS  The o n l y  case o f p r e d a t i o n d u r i n g the s t u d y was by a  0  rams were counted i n the h a r v e s t a b l e t h r e e - q u a r t e r horn  group i n i 9 6 0 .  From l i f e t a b l e d a t a i t i s e s t i m a t e d t h a t  curl  thirteen  such rams can be h a r v e s t e d a n n u a l l y on a s u s t a i n e d y i e l d b a s i s , w i t h allowance f o r r e c r u i t m e n t . 22.  F i f t y f o u r rams have been h a r v e s t e d from t h e h e r d s i n c e i n c e p t i o n o f an annual open season i n 1955.  The number o f hunters has i n c r e a s e d  y e a r l y , b u t h u n t e r success has n o t i n c r e a s e d p r o p o r t i o n a t e l y .  No rams  o v e r n i n e y e a r s o f age have been bagged, and t h e mean age o f h a r v e s t e d rams has dropped 23«  c o n s i d e r a b l y s i n c e 1955*  H a r v e s t i n g rams has n o t caused a d e c l i n e i n h e r d numbers, nor has i t s i g n i f i c a n t l y unbalanced  24.  the ram-to-ewe r a t i o .  The A s h n o l a h e r d undertakes basis.  a s e a s o n a l r e m i g r a t i o n h a v i n g an a l t i t u d i n a l  There i s a d i f f e r e n t i a l m i g r a t i o n o f t h e sexes w i t h ram  groups  l e a v i n g the w i n t e r ranges e a r l i e r and r e t u r n i n g l a t e r t h a n ewe-lamby e a r l i n g groups.  Most o f t h e summer and w i n t e r ranges are r e l a t i v e l y  contiguous and no m i g r a t i o n s exceed twelve m i l e s . 25.  Average group  s i z e from 490 r e c o r d e d o b s e r v a t i o n s was  9.3  sheep.  117 26.  Ram,  ewe  and mixed groups v a r i e d c o n s i d e r a b l y i n s i z e t h r o u g h t h e  seasons. 6.1,  Average s i z e o f female groups was 12,6.  and o f mixed groups was  10.7,  o f male groups  was  Mixed groups were o n l y commonly  o b s e r v e d from October u n t i l F e b r u a r y .  Ewe  and ram groups were e n t i r e l y  d i s t i n c t on t h e summer range, 27.  Both r u t t i n g areas.  and lambing a c t i v i t i e s were c o n f i n e d t o t h e w i n t e r range  The peak o f r u t t i n g  November.  from mid t o l a t e  The lambing p e r i o d extended from l a t e A p r i l u n t i l l a t e  w i t h a peak i n l a t e 28.  a c t i v i t y , i n i 9 6 0 , was  June  May.  Management s u g g e s t i o n s f o r t h e A s h n o l a herd i n c l u d e c o n t i n u e d h a r v e s t i n g under t h e t h r e e - q u a r t e r c u r l r e g u l a t i o n , annual a i r and ground c e n s u s i n g , i n c r e a s e d deer h a r v e s t i n g i n t h e a r e a and a c q u i s i t i o n w i n t e r ranges by government a g e n c i e s f o r game u s e .  o f important  APPENDIX TABLE 1 LOCATION OF LINE POINT TRANSECTS ON ASHNOLA RANGES  Transect Number  Date  1  June 13, I 9 6 0  2  June 13,  I960  3  June 14,  I960  4 5  June 15, June 15,  I960 I960  6  June 1 6 ,  i960  7  June 1 6 ,  i960  8  June 1 6 ,  i960  11 12 13  June June June June June  9,  1961 1961  lit  Aug. 5,  i960  15  Aug. 5,  9 10  9, I960 10, i960 6, 1961  7,  I960  Location South Slope at exclosure p l o t number 3. South Slope at exclosure p l o t number 4. South Slope, U00 yards east o f exclosure p l o t no. 3 Lower bench o f South Slope. South Slope bench near exclosure p l o t No. 6 South Slope, above p l o t number 5. South Slope at exclosure p l o t number 7. South Slope at exclosure p l o t number 8. Juniper Slope Juniper Slope Starvation Flats R e l i c t Slope Crater Mountain spring range Crater Mountain at exclosure p l o t number 9 . Crater Mountain at exclosure p l o t number 1 0 .  Elevation  5000  ft.  4,300 f t . 5,200 f t . 4000 f t .  4ooo  ft.  5,4oo  ft.  5,8oo-•6000 f t . 4,5oo 5,8oo 5,5oo 4,4oo 4,5oo  ft. ft. ft. ft. ft.  4,5oo  ft.  5,200 f t .  5ooo  ft.  APPENDIX TABLE 2 SUMMARIZATION OF DATA OBTAINED FROM 8/ LINE-POINT TRANSECTS ON SOUTH SLOPE  P e r c e n t o f t o t a l p l a n t cover Species  Transect-Nov"  Agropyron spicatum Koeleria cristata Poa s p . S t i p a columbiana Festuca idahoensis Carex s p . TOTAL GRASS AND SEDGE Achillea millefolium A l l i u m cernuum Taraxacum o f f i c i o n a l e Antennaria sp. Arabis sp. Potentilla nutallii O x y t r o p i s and A s t r a g a l u s Phacelia sp. Zygadenus venenosus Erigeron sp. Castilleja angustifolia Circium sp. Penstemon p r o c e r u s Lupinus s p . TOTAL PORBS Artemisia f r i g i d a A. dracuncuius Eriogonura h e r a c l o i d e s TOTAL CHAMAEPHTTES Moss  - "1  k 27  16  tr.  2  3  k  28 26 10 1  26 17  22 15  tr.  kl 6  tr.  10  9 5  tr.  3  tr. tr.  18 5  2k 3  k k 12 3  tr.  8  tr. tr.  Plants  lil  20  2k  7  8  29 30 8  kl  40  k  72  k k 3  tr.  tr.  5 tr. tr.  21 20 9  29  k  k k 1 tr.  k6 1 45 8  t r . equals l e s s than one p e r c e n t  3  tr.  tr.  15 5  28  6  tr.  tr. tr.  67  68  1 1  2  tr.  tr.  6  1 3  Q  tr.  tr.  tr.  tr. tr.  tr.  14 12  7  19  3  30 11  11 3  14  k  1 3 16 10  8  10 13 2  3 7  l£  tr. tr.  tr.  19  tr.  Percent Living Litter Soil Rock  10  6  ho 12 36 12  38  7 32  23  3  k  g 1  1  k  2  tr.  21 7  8 17  4 11  3 20  £8 20  39 6 46 9  Occurrence  k9 19 26 6  occurrence.  57 18 21  k  5o 5 38 7  14 8  120 APPENDIX TABLE 3 SUMMARIZATION OF DATA OBTAINED FROM 7 LINE-POINT TRANSECTS ON ASHNOLA RANGES  Species  T r a n s e c t No.  Agropyron spicatum Koeleria cristata Poa s p . Festuca Idahoensis S t i p a columbiana Broraus tectorum Carex s p . TOTAL GRASS AND SEDGE Achillea millefolium Antennaria sp. Balsamorhiza s a g i t t a t a Lupinus s p . Erigeron sp. A l l i u m cernuum Taraxacum o f f i c i o n a l e Agoseris glauca Verbascum thapsus O x y t r o p i s and A s t r a g a l u s Penstemon p r o c e r u s Delphinium b i c o l o r Geranium v i s c o s i s s i m u m Arabis sp. Zygadenus venenosus Plantago p a t a g o n i c a Lewisia rediviva Phacelia sp. TOTAL FORBS Artemisia f r i g i d a Eriogonum h e r a c l o i d e s Chrysothamnus nauseosus TOTAL CHAMAEPHYTES AND SHRUBS Living Plants Litter Soil Rock  9 4 tr.  16  20  tr.  Percent o f t o t a l p l a n t  10  11  12  13  9 2  1 18  59 7 1 10  9 11 19  32  5 tr.  48 6  8  19 18  6  tr. 62  5 1 tr.  tr. tr.  tr.  tr.  5 tr.  37  42 tr.  6  8 1 1  tr.  3  7  tr. tr.  tr.  3  28 21  2  42  23  56  47  111 3  tr.  49  13 17  5  tr.  19 11  2  77 4  10  tr.  tr.  tr. tr.  14  15"  38 17 17  34 15 9 20  tr.  72 3  78 2  3 7 5  11 2  3  tr.  2 23 3  tr.  tr.  tr.  5 2 2  tr.  2  26 4  2 5  ii  2 13 2 7 9  tr.  1 41  76  tr.  22 2  t r . equals l e s s than one p e r c e n t occurrence..  77 11 12  15"  6 tr.  tr.  3 9  3 2  3  5  52 4 38 6  66 8 21 5  P e r c e n t Occurrence  6 45 2  cover  86 1 10 3  121: APPENDIX TABLE k DATA FROM BIGHORN SHEEP COLLECTION NUMBER 1  South Slope, Ashnola, £000 f t . Location taken March 13, 1961 Date 11:30 A. M. Time Female Sex 7 years Age 62 i n . Total length 3k 3/k i n . Shoulder height 39 3/k i n . Chest g i r t h Iii ^ i n . Hind foot length T a i l length 3in. Ear length k\ i n . Whole wt. lk$ l b . Dressed wt. 96 \ l b . V i s c e r a l wt. kQ 3/k l b . Whole stomach wt. 21 3/k l b . Empty stomach wt. 5 3/k l b . Stomach content wt. 16 l b . Heart wt. 13 oz. (369 gm) L i v e r wt. 26 oz. (717 gm) Lungs wt. 2k oz< (681 gm) Spleen wt. 2.4 oz. (67.5 gm) Kidney wt. (both) k oz. ( I I 4 . 5 gm) Adrenal wt. r i g h t - 2 . 8 3 gm , l e f t - 3 . 1 1 gm Uterine membranes and placenta k l b . 8 oz. General condition Very good Pelage Starting spring molt None noted Abno rmali t i es Pregnant with male fetus i n l e f t uterine horn. Much evidence Remarks: of t i c k scars and bare spots where magpies have picked out t i c k s . Severe i n f e s t a t i o n of spinose ear t i c k . Good f a t reserves, e s p e c i a l l y p e r i c a r d i a l and kidney regions. Moderate numbers of pinworm (Skrjabinema ovis) stomach worm (Ostertagia sp.) and h a i r lungworm (Protostrongylus s t i l e s i ) .  122  APPENDIX TABLE 5 FETUS FROM BIGHORN COLLECTION NUMBER 1  Sex Weight Total l e n g t h Fore l e g length^ Hind l e g l e n g t h Estimated period of development 1  3  male 4 l b . 5 Oa. (1,962 gm.) lit 3/4 i n . (37.5 cm.) 4 3/8 i n . (10.8 cm.) 5 5/8 i n . (l4.2 cm.) It months  s t r a i g h t l i n e , t i p of nose to rump ^olecranon process to hoof point ^calcaneum to hoof point  123 APPENDIX TABLE 6 DATA FROM BIGHORN SHEEP COLLECTION NUMBER 2  Ashnola, Starvation, 4,500 f t . Location taken Date May 11, 1961 Time 8:30 P. M. Sex male Age 8 years Total length 66 •§• i n . Shoulder height 39 i n . Chest g i r t h 43 i n . Hind foot length lhk i « T a i l length 4 3/k i n . Ear length k 3/k i n . Whole wt. 181 I l b . Dressed wt. 134 lb.. V i s c e r a l wt. 47| lb. Whole stomach wt. 29f l b . Empty stomach wt. 5 3/4 l b . Stomach content wt. 23j l b . I n t e s t i n a l wt. 11 l b . Heart wt.. 22 oz. (625 gm.) Liver wt. 38 oz. (1080 gm.) Lungs wt. 36 oz. (1024 gm) Spleen wt. 5.5 oz. (150 gm.) Kidney wt. (both) 8.5 oz. (240 gm.) Adrenal wt. right-3.23 gm., l e f t - 3 . 2 5 gm.) Testes wt. 8.0 oz. (224 gm.) General condition Good Pelage Part summer, part winter coat. Abnormalities Only 2 i n c i s o r s present Remarks: Winter t i c k (Dermacentor albipictus) and spinose ear t i c k (Otobius megnini) i n moderate numbers. Moderate infestations of stomach worms (Ostertagia sp.) i n abomasum and whipworms (Trichuris ovis) i n large i n t e s t i n e . Light i n f e s t a t i o n of hair lungworm ( Pro to strongylus s t i l e s i ) i n lungs. No inflammation noted. n  12k  LITERATURE CITED Andrewartha, H. G., and L. C. B i r c h . 1 9 5 4 . The d i s t r i b u t i o n and abundance of animals. Chicago: Univ. Chicago Press. 782 pp. Brink, 7. C , and L. ¥. Farstad. 1 9 4 9 . The physiography o f the a g r i c u l t u r a l areas o f B r i t i s h Columbia. S c i . Agric. 29:273-301 B r i t i s h Columbia. 1 9 1 0 - 1 9 5 0 . Annual reports o f the B r i t i s h Columbia Game Department, Gov't, o f B. C , V i c t o r i a . Brown, Dorothy. 1954• Methods o f surveying and measuring vegetation. Commonwealth A g r i c u l t u r a l Bureaux, Farnham Royal, Bucks, England. 223 pp. Buechner, Helmut K. I960. The bighorn sheep i n the United States, i t s past, present, and future. W i l d l i f e Society. W i l d l . Monograph No. 4. 174 pp. Cable, Raymond M. 1 9 5 8 . An i l l u s t r a t e d laboratory manual o f parasitology. Burgess. Fourth Edition, 165 pp. Chapman, J . 0 . 1 9 5 2 . The climate o f B r i t i s h Columbia. Paper presented to. the F i f t h B. C. Natural Resources Conference ( 1 9 5 2 ) . Couey, Faye M. 1 9 5 0 . Rocky Mountain bighorn sheep o f Montana. Montana F i s h and Game Comm. B u l l . 2 . 90 pp.  Helena:  Cowan, Ian M^aggart. 1 9 4 0 . D i s t r i b u t i o n and v a r i a t i o n i n the native sheep of North America. Amer. Midi. Nat., 24 ( 3 ) : 5 o 5 - 5 8 0 . . 1 9 4 7 . Range Competition between mule deer, bighorn sheep and elk i n Jasper Park, Alberta. Trans. N. Amer. W i l d l . Conf., 1 2 : 2 2 3 - 2 2 7 . . 1 9 5 1 . The diseases and parasites o f big game mammals o f Western Canada. Proc. Ann. Game Conv., B. C. Game Dept., 5 : 3 7 - 6 4 . .  1950-1955.  Unpublished f i e l d notes.  Dalquest, W. W. and D. F. Hoffmeister. 1 9 4 8 . Mountain sheep from the State of Washington i n the C o l l e c t i o n o f the University o f Kansas. Trans. Kansas Acad. S c i . , 5 l ( 2 ) : 2 2 4 - 2 3 4 . Dasmann, W. P. 1 9 5 1 . Some deer range survey methods. Game, 37 ( l ) : 4 3 - 5 2 .  C a l i f . Fish and  Daubenmire, R. F. 1 9 4 0 . Exclosure technique i n ecology. E c o l . 21:5l4-5l5» . 1959« Plants and environment. Second Edition, 422 pp.  New York: John Wiley and Sons.  Deevey, Edward S., J r . 1947. Life tables for natural populations of animals. Quart. Rev. B i o l . , 22 (4):283-314. Dyksterhuis, E . J . 1949. Condition and management of rangeland based on quantitative ecology. J . Range Mgmt. 2 (3):104-ll5» Edwards, R. T . 195>6. Snow depth and ungulate abundance i n the mountains of western Canada. J . Wildl. Mgmt., 20 (2):l59-l68. Edwords, C. E . 1893. Campfires of a naturalist. Marston and Company.  London: Sampson Low,  Flucke, A. F. 19$$, A history of mining in British Columbia. Col. Nat. Res. Conf., 8:6-26.  Tran. B r i t .  o  Forrester, D. J . I960. A preliminary investigation of the prtostrongylin lungworm-bighorn sheep relationships in Montana. M.S. thesis. Montana State University. From summary of thesis i n the annual report of the Montana Cooperative Wildlife Research Unit, Montana State University, Missoula, June 30, I 9 6 0 . Green, H. V. 1949. The bighorn sheep of Banff National Park. Ottawa: National Parks and Historic Sites Service, Development Services Branch. $3 pp. Grinnell, G. B. Heape, W. 1932.  1928.  Mountain sheep.  J . Mammal., 9 ( l ) : l - 9 .  Emigration migration and nomadism.  Cambridge: Heffer.  Honess, R. F . , and N. M. Frost. 1942. A Wyoming bighorn sheep study. Wyo. Game and Fish Dept. Bull, No. 1. 1 2 7 pp. Hornaday, W. T. 1901. Notes on the mountain sheep of North America, with a description of a new species. N. T. Zool. Soc. Ann. Rept., 5:77-122. Hunter, G. N., and R. E. Pillmore. 1954* Hunting as a technique i n studying lungworm infestations i n bighorn sheep. Trans. N. Amer. Wildl. Conf., 19:117-131. Jones, F. L . 193>0. A survey of the Sierra Nevada bighorn. B u l l . , 3$ (6):29-76.  Sierra Club  Julander, Odell. 1958. Techniques in studying competition between big game and livestock. J . Range Mgmt. 11 (1):18-21. , and W. L . Robinette. 1950. Deer and cattle range relationships on Oak Creek range in Utah. Jour. Forestry, 48:4lO-4l5« Kelker, G. H. 1947. Computing the rate of increase for deer. Mgmt., 11 (2):177-183.  J . Wildl.  Klein, D. R. and S. T. Olson. I960. Natural mortality patterns of deer i n Southeast Alaska. J . Wildl. Mgmt. 24 (l):80-88.  126; Krajina, V. J . 1 9 5 9 . Bioclimatic zones i n British Columbia. Vancouver: The University of British Columbia, Botanical Series No. 1. Lack, David. 1954. The natural regulation of animal numbers. The Clarendon press. 343 pp.  Oxford:  Larkin, P. A. 1956. Interspecific competition and population control in freshwater fish. J . Fish. Res. Bd. Canada, 1 3 (3):327-342. 1933.  Leopold, Aldo. 481 pp.  Game management.' New Tork:Charles Scribner's Sons.  Martin, P. W. i960. Range survey Ashnola sheep range. Unpublished report, British Columbia Game Department. 4 pp. Typewritten. 1956.  M^ann, L . J .  Ecology of the mountain sheep.  56 (2):297-324.  Amer. Midi. Nat.,  Mills, Harlow. 1937. A preliminary study of the bighorn of Yellowstone National Park. J . Mammal., 18 (2):205-212. Mosby, H. S. (Ed.) i960. Wildlife Society.  Manual of game investigational techniques.  The  Monro, J . A. and I . M°T. Cowan. 1947. A review of the bird fauna of British Columbia. Victoria:British Columbia Provincial Museum, Special Publication No. 2. 285 pp. Murie, Adolph. 1944. Printing Office. Odum, E . P. 1953. Company.  The wolves of Mount M Kinley. WashingtonGovernment U. S. Nat. Park Service, Fauna Series No. 5 . 238pp. c  Fundamentals of ecology.  Philadelphia:W. B. Saunders  Pechanec, J . R. 1936. Comments on the stem-count method of determining percentage utilization of ranges. Ecol. 17 (2):329-331. Phillipps-Woolley, C. 1888. and Son. 261 pp.  A sportsmans eden.  London:Richard Bently  Rowe, J . S. 1 9 5 9 . Forest regions of Canada. Ottawa:Department of Northern Affairs and National Resources, Forestry Branch. Bull. 123. 7 1 pp. 1949.  Rowles, C. A.  2:4-28.  Sampson, A. W. 570 pp.  1952.  Soil outline.  Trans. B r i t . Col. Nat. Res. Conf.,  Range management.  New York:John Wiley and Sons, INC.  Smith, D. R. 1954. The bighorn sheep in Idaho, its status, l i f e history, and management. Idaho Dept. Fish and Game, Wildl. Bull, No. 1, 154 pp. Smith, E . R.  i960.  Dec. 19, I960.  Unpublished report to Chief Forester, Kamloops, B. C ,  7 pp. Typewritten.  127' Smith, J . G. and 0. J u l a n d e r . 1953* Deer and sheep c o m p e t i t i o n i n Utah. J . W i l d l . Mgmt., 17 (2):101-112. Spencer, G. C. 1943. Notes on t h e l i f e h i s t o r y o f Rocky Mountain b i g h o r n sheep i n t h e T a r r y a l l Mountains o f C o l o r a d o . J . Mammal., 24 ( l ) : l - l l . S p i l s b u r y , R. H. and E . W. T i s d a l e . 1944* S o i l - p l a n t r e l a t i o n s h i p s and v e r t i c a l z o n a t i o n i n t h e Southern I n t e r i o r o f B r i t i s h Columbia. S c i . A g r i c . 24:395-436. Sugden, L . G. 1961. (M.S.). The C a l i f o r n i a b i g h o r n i n B r i t i s h Columbia w i t h p a r t i c u l a r r e f e r e n c e t o t h e Churn Creek h e r d . T e i t , J . A.  1930.  The S a l i s h a n t r i b e s o f t h e western p l a t e a u s .  Ann. Rept. B u r . Amer. E t h n o l .  PP 23-395.  T i s d a l e , E . W. Columbia.  1947. Ecol.  Washington:Government  The g r a s s l a n d s o f t h e s o u t h e r n i n t e r i o r o f B r i t i s h  28:346-382.  , A. M Lean and S. E . C l a r k e . management i n B r i t i s h Columbia. c  45th.  Printing Office.  1954. Range r e s o u r c e s and t h e i r J . Range Mgmt., 7 (l):3-9«  Urquhart, F. A. 1958. A d i s c u s s i o n o f t h e u s e o f t h e word m i g r a t i o n as i t r e l a t e s t o a proposed c l a s s i f i c a t i o n f o r animal movement. T o r o n t o : C o n t r i b u t i o n s o f t h e R o y a l O n t a r i o Museum, D i v i s i o n o f Zoology and P a l a e n t o l o g y , No. 50. Vrooman, C. W. 194l« A h i s t o r y o f r a n c h i n g i n B r i t i s h Columbia. A n n a l i s t , 11 (2). W i l l i a m s , A. B. 1925. S c r i b n e r ' s Sons.  Game t r a i l s i n B r i t i s h Columbia. 360 p p .  Econ.  New Y o r k : C h a r l e s  

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