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Aspects of the winter ecology of black-tailed deer Odocoileus hemionus columbianus Richardson on Northern… Jones, Gregory William 1975

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ASPECTS OF THE WINTER ECOLOGY OF BLACK-TAIIED DEEP JCdccoileus hemionus columfcianus Richardscr.) ON NCST HEBN VANCOUVER ISLAND by GREGORY WILLI A K JCNES B.Sc., University of British Columbia, 1971 A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE CF MASTER OF SCIENCE in the Faculty of FORESTRY We accept this thesis as conforming to the required standard THE UNIVERSITY OF LETTISH - CCIUKEIA Harch, 1975 In p r e s e n t i n g this thesis in partial fulfilment of the r e q u i r e m e n t s for an advanced degree at the U n i v e r s i t y of British C o l u m b i a , I a g r e e that the Library shall m a k e it freely a v a i l a b l e for reference and study. I further agree that p e r m i s s i o n for e x t e n s i v e copying of this thesis for scholarly p u r p o s e s may be g r a n t e d by the Head of my D e p a r t m e n t or by his r e p r e s e n t a t i v e s . It is u n d e r s t o o d that copying or p u b l i c a t i o n of this thesis for financial gain shall not be allowed without my writ ten pe rm i ss ion . Depa rtment The University of British Columbia 2075 Wesbrook Place Vancouver, Canada V6T 1W5 ABSTRACT Black-tailed deer JOd cccileus h£2li22jy5 columlianus Kichardson) were studied in the Eimpkish Valley on northern Vancouver Island to determine the effects of clearcut legging upon the ecology of the deer in winter. Eecause Erovincial government biologists suspected that logging was decreasing the amount of winter range, and therefore the number cf deer, cn Vancouver Island, most emphasis was placed upon the interrelationships between logging, sncw depth, habitat selection by deer, aid nutritional condition of deer. The study was dene during during the winters of 1 S 7 1 - 7 2 and 1 9 7 2 - 7 3 . The first winter was severe and had heavy snowfall, and the second winter was mild and had light snowfall. If deer sink deeper in snow than their chest height, they have a hard time moving. In the Nimpkish Valley, fawns had chest heights of about 17 inches, and adults about 22 tc 23 inches. During the first winter, snow in the logged habitats averaged 4 ft deep, but snow in the mature timber habitats averaged less than 2 ft deep. There was more sccw at high elevations than at lew elevations. Snow was less deep than deer chest height only in mature timber habitats at low elevations. Snow was also shallowest in mature timber habitats having a high crown closure. During the >severe winter, enly mature tiaber habitats at low elevations with crown closures greater than 65* were used heavily by deer. ii The most important aspect of snow is net siirple srew depth, but how deeply deer sink in it. When a hard crust formed on deep snow in the regenerated logging slashes, deer were able tc neve freely on top of the crust, and made heavy use cf these areas for feeding. Deer also used mature timber habitats heavily during the mild winter. Deer made more use of timber habitats having a shrub understory than these having a conifer understory, probably because there was more food available in the timber having a shrub understory. Many deer remained as high up the mountains as snow conditions and food availability permitted. Generally, deer made light use of the logged habitats during both winters, but they used these habitats heavily in the spring. Deer were collected to measure their food habits and physical condition. Deer were not able to eat as nany plant species in the severe winter as in the mild winter, and were in worse physical condition in the severe winter than in the mild winter. In the Nimpkish Valley, deer made heavy use cf nature timber habitats during winter. In many other areas of western North America, black-tailed deer use logged habitats fcr winter range. However, the Nimpkish Valley is much more mountainous and has more snowfall than many other areas iji which deer ecology has been studied. The habitat selection patterns of deer in the Ni mpkish Valley probably occur only in areas havirg similar topography, vegetation, and climate. Most other studies of black-tailed deer have cctcluded that logging is beneficial tc deer. However, continued clearcut logging in the regions of Vancouver Island having high snowfall will eliminate deer winter range and reduce deer populations. It is recommended that legging companies leave strips of mature timber, going from the subalpine tc the valley bottom, and including winter range habitats, in all those areas nbere deer populations are desired. iv TABLE CF CONTENTS 1 . I N T R O D U C T I O N 1 1 . 1 D e f i n i t i o n o f t h e p r o b l e m 1 1 . 2 O b j e c t i v e s a n d s c o p e 1 2 . STUDY AREA AND STUDY PEBIOD 2 2.1 Description of the study area ........................ 2 2.2 Period of field work 3 3. STUDY METHODS 5 3.1 Classification of habitat types ...................... 5 3.2 Kinds of data collected 6 3.2.1 Eeer-use data 6 3.2.2 Deer collection data 10 3.2.3 Deer movement data 12 4 . RESULTS 12 4 . 1 A b i o t i c d a t a 12 4.1.1 Comparison cf the winter of 1971-72 with the winter of 1972-73 12 4.1.2 Relationships between snow depth, elevation, ar.d crown closure 16 4.2 Vegetation in the habitat types 16 4.3 Winter and spring food habits 18 4.3.1 Food habits during the severe winter of 1371-7 2 .. 18 VI 4.3.2 Food habits during the miia winter of 1972-73 .... 19 4.3.3 Summary and discussion 24 4.4 Winter habitat selection by deer 25 4.4.1 Habitat selection during the severe winter of 1971-72 25 4.4.2 Habitat selection during the mild winter of 1972-73 28 4.4.3 Characteristics of winter range habitats 36 4.5 Movements of deer 44 4.6 Chest heights of deer 47 4.7 Summary and discussicn 47 4.8 Condition of deer 51 4.8.1 Deer condition over the winters of 1971-72 and 1972-73 52 4.8.2 Relationships between deer condition and the sex and age of deer 52 4.8.3 Summary and discussicn ........................... 55 5 . DISCUSSION 56 5.1 Effects of winter weather cn deer 57 5.1.1 Relationships between deer condition, mortality rates, and winter weather 57 5.1.2 Relationships between winter weather and deer reproduction 59 5.2 Ecological mechanisms mitigating the effects of winter weather on deer ............................ 60 VI 5.3 Management reccn irendaticns 64 REFERENCES 67 Vll LIST OF TABLES Table 1. Percent plant cover on the permanent track ccunt plots as measured in the autumn of 19*72 (mean ± st. dev.) . Table 2. Correlations of the deer-use indices with ether habitat measures taken during the winter of 1972-73. Table 3. Deer-use of logged and mature timber habitats during the winter and spring of 1972-73 (near ± st. dev.). Table 4 . Deer-use cf nature timber habitats having a shrub understcrj and a conifer understory, during the winter and spring of 1972-73 (mean ± st. dev.). Table 5 . Chest heights cf deer (mean ± st. dev.) . Table 6. Deer condition indices (mean ± st. dev.). viii LIST OF FIGURES Figure 1. Location of the Nimpkish Valley study area on northern Vancouver Island. Figure 2 . Monthly snowfall at Hess Camp. Figure 3. Relationship between snow depth and elevation. Figure 4. Relationship between snow deptfc and crcwr closure. Figure 5. Percent vcluie cf the fcod types in the rumen samples. Figure 6 . Percent occurrence of the fcod types in the rumen samples. Figure 7 . Percent volume of the species in the runen samples. Figure 8. Percent occurrence of the species in the rumen samples. Figure 9. Range and median of the deer-use indices taken during the winter cf 1971-72. Figure 10. Location of the track count plots on Kt. Cain. Figure 11. Location of the track count plots cn Abel Ridge. Figure 12. Deer-use cf clear slash habitats during the winter and spring cf 1972-73. Figure 13. Deer-use of two clear slash areas during the winter and spring of 1972-73. Figure 14. Effect of snow on deer-use of a clear slash area during the winter of 1972-73. Figure 15. Regression cf whele weight against eviserated weight. ix LIST OF APPENDICES Appendix 1. Appendix 2. Appendix 3. Appendix 4. Appendix 5. Methods used to count deer tracks and measure snow depths during the winter of 1971-72. Design of the permanent track ccunt plots used during the winter of 1972-73. Method used tc analyse the deer rumen samples. Summary of the track count cata taken during the winter of 1971-72. Botanical names of the plant species discussed in the text. mclxxx A C K N O W L E D G E M E N T S The study was partially financed by the Eritish Columbia Fish And Wildlife Branch through the efforts cf regional biologist Ian Smith. The University cf British Columbia, Faculty of Forestry, provided additional funds through the efforts of Fred Bunnell. Canadian Forest Products Limited provided accommodations and use of some company facilities. The Vancouver Island Wildlife Federation generously provided the funds required to purchase radio collars for deer and a radio receiv er. Dick Marshall of the Canada land Inventory supplied some of the thermograph equipment used and compiled the temperature data. Hilla Noble cf the B.C. Fish and Wildlife Eranch analyzed the deer rumen samples. Kerry Clark, Chris Schmidt, Eruce Moir, Ken Hasebe, Jim Anderson, Can Stevens, and Jim Rcchelle provided valuable assistance in the field work. The study was prcpcsed by Ian Smith and supervised by Fred Bunnell, both of whom provided much assistance in plarring the field work. Byron Mason and Charles Veasey of Nanaimo provided detailed knowledge cf deer winter range and without their assistance much of the feel for the winter range prcblem wculd have been lost. Fred Bunnell, Dennis Chitty, Ian Smith, and Ian KcTaggart Cowan reviewed the manuscript and made many helpful suggestions. Dorothy Whitehcuse and Penny Lewis typed the tables and text under demanding conditions. To these individuals and organizations I making the thesis a reality. xi give ay thanks for 1 1 . I N T R O D U C T I O N 1.1 Definition of the problem In many areas, black-tailed deer JOdcccileus hejricnus columtianus Richardson) prefer early serai types as winter range. There is more food available in the early serai types, ana the plants in the early serai types are often more nutritious (Brown, 1961; Einarsen, 1946; Gates, 1968). Until recently, many biologists felt that en Vancouver Island, deer use early serai types for winter range. However, some previous workers suggested that in those regions of Vancouver Island where winter is severe, deer require mature timber serai types as shelter from deep snow (Cowan, 1956; Edwards, 1956) . Similarly, in high snow areas deer populations have decreased when all timber has been removed (Edwards, 1956; Smith, pers. comm.). If deer depend en mature forest for winter survival, then continued clearcut logging in the regions of Vancouver Island having high snowfall will result in lewer deer populations. The purpose cf this study is to investigate the winter ecology of black-tailed deer in the regions cf Vancouver Island having high snowfall. 1.2 Objectives and scope The study was designed to determine the relationships between clearcut logging and the winter ecology cf deer. The hypothesis was that legging decreases winter range because mature timber is necessary for shelter from deep snow. I 2 originally attempted to study the effects of lcggirg cn the winter ecology of deer by measuring deer-use of logged and unlogged habitats, within classes of aspect ar.d elevation. However, this approach was too simple to produce meaningful results, and therefore I included some relationships between environmental conditions, habitat selection, acd physical condition of deer, and also described some characteristics cf deer winter range habitats. This study was intended to be useful in the management of deer, ana in planning further research. The study does not deal in depth with any single tcpic cf deer winter ecology, but deals superficially with several related topics, and thus provides an overview cf deer winter ecology. The specific topics examined include: 1) vegetation characteristics of various habitat types, 2) food habits of deer, 3) deer-use of habitat types, 4) effects of vegetation, snow, and season (winter versus spring) on deer-use of habitats, 5) movements of deer, 6) physical condition cf deer, 7) chest heights of deer. 2 . STUDY AREA AND STUDY PERIOD 2.1 Description of the study area The study area is located in the Nimpkish Valley on 3 northern Vancouver Island (Figure 1), and most field work was done near the Davie River. Since the Davie River is a major tributary of the Nimpkish River, the study area is referred to as the Nimpkish Valley. Willms (1971) described tbe trajcr ecological characteristics of the Nimpkish Valley, and his description is summarized below. The Nimpkish Valley was glaciated in the Pleistocene, and therefore the soils are deep only on the valley bcttcn, and outcroppings of bedrock are common on the sidehill areas. Most of the valley area below 2000 ft elevation has been burned by wildfire within the last 1000 years. Logging in parts cf the valley outside the study area began in 1915, but logging in the study area itself began in 1947 and continues at present. The valley bottoms and some of the sidehill areas were progressively clear cut, but at present, most logging settings are separated by mature timber which is left unlogged for 3 or icre years. The Nimpkish Valley is uountainous, with many peaks higher than 4000 ft, and there is often much snow during winter (Figure 2). The following biogeoclimatic zones are present in the study area: .Set Douglas Fir, Dry Western Hemlock, Wet Western Hemlcck, Mountain Hemlock (subalpine), and alpine (Packee, 1972). Most of the field work was done within the Dry Western Hemlock and the Wet Western Hemlock zones, although some work was dene in the other zones. 2.2 Period of field work Most of the field work was done in the consecutive winters F i g u r e 1 L o c a t i o n o f the Nimpkish V a l l e y s t u d y on n o r t h e r n Vancouver I s l a n d 4a 5 of 1971-72 and 1972-73, with preliminary field work from September through November, and intense study frcm December through April. Soire additional data on deer movements were collected from May of 1973 through February of 1971. 3 . STUDY METHODS 3.1 Classification cf habitat types In order to measure deer-use of different habitats, measurable parameters must be used to classify habitat types. Initially, habitats were classified according tc serai type, elevation, and aspect, because previous workers have considered these variables important to deer winter range (Gates, 1968; Loveless, 1967). Three classes of serai type and elevaticr*, and two classes of aspect were used. The serai types distinguished are clear slash, second-growth s l a s h , and mature timber. Clear slash refers to logged areas without obvious ccnifer regeneration, second-growth slash refers to logged areas having obvious conifer regeneration, and mature tinter refers to unlogged habitats. Where appropriate, clear and second-growth slash habitats are called logged habitats. The elevation classes used were low (500-1500 ft.), medium (1500-2500 ft.) and high (2500-4000 ft.).' The aspects used were south-facing and north-facing slopes. South aspects include all aspects from west through south to southeast, and north aspects include all other aspects. 6 3.2 Kinds of data collected I collected data describing all cf the study tcpics listed in section 1.2, and have organized the methods according tc the type of data collected. 3.2.1 Eeer-use data Three methods were used to measure deer-use: 1) deer track counts in the s n o w , 2) daytime deer counts, 3) nighttime deer ccunts. 3.2.1.1 track count plots I counted deer tracks in the snow to obtain instantaneous indices of deer-use,and attempted to count only tracks that were less than one-day o l d , but varying weather conditions often made tracks difficult to age. A different design of track ccunt plot was used during the second winter than the first, and the method used during the second winter is described later. During the first winter, a radial plot design was used to measure deer-use (Appendix 1). The plots were temporary and unmarked, and the centre cf each plot was a fresh deer track. All plot centres were at least 100 feet apart, and each plot consisted of four 50-foot long compass lines radiating in the cardinal directions. 7 The instantaneous deer-use index is the total rutrber cf tracks crossed by the fcur ccrapass lines. It was difficult to count tracks accurately when there were more than four or five tracks on each 50-foot line, and the centre track was ccurted only if it crossed a 50-fcot lina. If a track crossed a 50-foot line twice or more, it was counted cnly once. It was often impossible to determine if a track crossed more thar ere 50-fcct line. I walked through the area under study and took track-count data as deer tracks were encountered. I walked through the area in one direction, such as uphill, downhill, or sidehill. Eighteen snow depth measurements were taken it seme areas sampled with track count plots (Appendix 1). The snow depth for the area is the mean of the eighteen measures. 3.2.1.2 daytime deer counts I counted deer in daylight logged and unlogged habitat types, techniques to see deer. The deer-us searching time. 3.2.1.3 nightime deer counts I counted deer at night to measure deer-use cf clear slash habitats. My assistant and I each had a spotlight, and we counted deer as I drcve the truck at 5 to 15 mph. The measure of to measure deer-use cf both and used ordinary hunting e index is deer seer per unit 8 deer-use is deer seen per mile of road. I counted deer on twelve transects, totalling 2C.5 miles cf road, at intervals cf approximately two weeks, tut occasionally missed some transects because of had weather. It was net normally possible tc count all the transects in ere right, so the counts were taken ever several nights. There were 9 sampling periods, and for data analysis it was assumed that all counts were done on the middle date cf the sampling periods. 3.2.1.4 permanent track count plots The results of the first year of field work suggested that aeer-use of habitats was influenced by mere than elevation, aspect, or serai type. Consequently, I designed a permanent plot from which the following data were collected: 1) deer-use, measured by track counts, \ 2) percent cover cf seme plant species, 3) deer track depth in the s n o w , 4) snow depth, 5) estimate of the abundance cf lichen litterfall. I also recorded the elevation, aspect, serai type, and percent crown closure of each plot. Most of the permanent plots were located in areas visited during the winter cf 1971-72. Each permanent plot consisted of 20 subplots, and the design of the plots is shewn it Appendix 2. 9 The number of fresh deer tracks in the snow between each pair of subplots was counted, and the deer-use index for the plot is the mean cf the 15 individual track count samples. The snow depth at the centre of each subplot was measured, and the snow depth for the plot is the mean of the snow depths cn each subplot. I measured deer track depth from 5 clear footprints of a representative track that crossed the track ccunt line, but did not measure track depths from all track ccunt lines. The individual track depth is the mean of the measures taken from a single track, and the track depth for the plot is the icean cf the individual track depths. The abundance cf lichen litterfall iAlectoria sp only) was estimated on a four point scale: 0 , 1 , 2 , 3. fi value of '0' \ indicates that no lichen vas available, '1' indicates that lichen litterfall was "light", •2' indicates that lichen litterfall was "medium", and '3« indicates that lichen litterfall was "heavy". The lichen index for the plct is the mean of the indices from the 20 subplcts. The percent cover cf vegetation on each subplot was measured, excluding plant species which are conncnly less than 1 ft high, and considering only plants with living parts above ground during winter. I measured the maximum length and width of each species-specific clump of vegetation, and rcunded all measures to the nearest one-quarter foot. The horizontal coverage was then calculated as the area of an ellipse. If there were a large number of small clumps, the percent ccver was estimated. High overhanging branches were excluded from the 1 0 vegetation data. I measured the percent crcwn closure cf the nature timber plots by using a 35-nm single lens reflex camera to photograph the canopy directly above the centre of each subplct. A wide-angle lens (focal length = 35 mm) i>as used on the canera. I tcck the percent cover by delineating cancpy and non-canopy on a 3.5 by 5 inch print, and using a dot grid (64 dots per square inch) to measure percent cover from a 2 inch by 2 inch square at the centre of the print. The crown closure measure was rounded to the nearest 5 * , and the crown closure measure fcr the plct is the mean of the measures from the 20 subplots. It was impossible tc collect many data from the low elevation plots because of the unusually light sncwfall during the winter of 1972-73, and 16 cf the 19 permanent plots were in low elevation habitats. Therefore, 5 unmarked temporary plots, identical to the permanent plots, were measured in varicus high elevation habitats where there was a significant snowpack. All temporary plots were placed in mature timber habitats 3400 ft or more in elevation. 3.2.2 Deer collection data I collected deer in late January and late March of each year and took the following data from each deer collected: 1) whole weight and eviserated weight, 2) total weight of kidney fat, 3) chest height (sternum tc tip cf nail). 1 1 t») a rumen sample. I modified the method of Anderson, Medin, and Bcwden (1972) to calculate an index cf deer ccnditicn: Ic = F/W x 100 Ic = deer condition index F = mean kidney fat weight of the twc kidneys W = whole weight of the deer. Anderson, Medin, and Bcwden (1972) trimmed the kidney fat square with the kidney, but I did not do this because I felt that their method introduces bias into the results. I assuae that the deer condition index is directly prcpcrticnal to "nutritional condition" or the "ability to survive winter stress". A lab technician analyzed the rumen samples, using the standard method employed by the British Columbia Fish and Wildlife Branch (Appendix 3). The plants eaten were classified into 8 food types: conifers, shrubs, forts, ferns, lichens, mosses, liverworts, and miscellaneous; and the percent volume and percent occurence of individual species and feed types in the rumen samples was calculated. The species listed in Figures 7 and 8 include only the most common species found in the rumen sa mples. I a l s o s a m p l e d d e e r in N o v e m b e r cf 1 9 7 2 , t u t t c c k enly the d a t a n e c e s s a r y to c a l c u l a t e the c c n d i t i c n i n d e x f r o m t h e s e 1 2 sa mples. 3.2.3 Deer movement data I used radio telemetry tc study deer movements and tagged one deer in January cf 1973 and six in April of 1973. I located the tagged deer from the ground and from fixed-wirged aircraft. 4 . RESULTS 4.1 Atictic data Snow data were taken because sncw has a great effect upon the ecology of deer in winter. An understanding cf the factors that influence sncw depth is essential for an understanding cf deer ecology. 4.1.1 Comparison cf the winter of 1971-72 with the winter of 1972-73 Huch more sncw fell during the winter of 1971-72 than during the winter of 1972-73 (Figure 2). The total snowfall at 500 feet elevation was 125 inches over the winter cf 1971-72, and only 10 inches over the winter of 1972-73. luring both winters, the snowfall at elevations above 500 feet was greater than the snowfall recorded in Figure 2. The data shew that the winter of 1971-72 was more severe than the average since 1S54, and that the winter of 1972-73 was less severe. However, neither winter was the most severe, or the least severe, winter on record. 15 F i g u r e 2 Monthly s n o w f a l l a t Woss Camp These d a t a were p r o v i d e d by Canadian F o r e s t P r o d u c t s L t d . and were c o l l e c t e d a t 500 f e e t e l e v a t i o n . SNOWFALL (inches) 6 0 " . 50". 40". 30". 2 0 " . 1 0 " . Nov March April May SB Figure 3 Relationship between snow depth and elevation These data were collected from December of 1971 through March of 1972 T e s t o f common e q u a t i o n : F = 4 7 . 1 9 p < 0 . 0 0 1 The slopes of the two equations are not different at the 51 level of significance 14a 1000 2000 3000 4000 ELEVATION ( f t ) Figure h Relationship between snow depth and crown clos These data were collected from January through March of 1973. These data were collected in mature timbe habitats above 3000 feet elevation 15a Y: 5.69 - 0.07X F:8.08 P:0.036 x 5 -1 I-CL LU ? O z w 1 -30 —i 1— 1 40 50 60 CROWN CLOSURE (%) —r~ 70 16 4.1.2 Relationships between snow depth, elevation, and crown closure Within the elevation range sampled during the winter of 1971-72, snow was deepest at high elevations and in the legged hatitats (Figure 3). Snow is less deep in the timber because the dense crown closure reduces the amount of fallirg snow that reaches the ground surface (Meirnan, 1968). In the Sinfkish study area, snow was about twice as deep in the logged hatitats as in the mature timber habitats (Figure 3 ) . A dense crcwr closure intercepts a greater proportion of a snowfall than an open crown closure, and therefore sncw depths decrease with increasing crown closure (Figure 4). Much of the variation shown in Figures 3 and undoubtedly arose from sampling over time and from sampling in different areas. H.2 Vegetation in the habitat types I measured vegetation because deer-use of habitats is influenced by vegetation. The vegetation data presented were taken from the permanent plots during the autumn cf 1972. I have presented only data describing several of the more ccnacn plant species found on the plots. Visual inspection of the data suggests that vegetation cover varied a great deal within serai types jTable 1). Fcr example, cover of Vaccinium sp in mature timber hatitats on south aspects, and between 500 and 1500 ft elevation, varied H a b i t a t type Winter range 1/ Elevation Y e a r s Crown s i n c e c l o s u r e b u r n i n g V a c c i n i u m spec, i es S a l a l Cedar 2/ Douglas f i r Western hemlock T r u e f i r C l e a r s l a s h ; No 1000 0 9 2 + 3 1 + 3 0 1 + 2 1 0 0 south a s p e c t No 1300 0 4 1 + 2 1 3 + 2 1 0 <1 + 2 0 No 1400 0 5 0 0 0 0 0 0 Second growth; No 1000 0 20 7 + 10 <1 9 + 13 13 + 19 1 5 + 2 3 0 south a s p e c t No ' 1 1 0 0 0 20 1 + 2 9 + 1 7 1 3 + 1 2 16 + 24 7 + 13 0 No 1300 0 19 <1 0 0 2 + 8 1 1 + 20 Mature t i m b e r ; Yes 1 1 0 0 75 ± 10 3 + 6 0 0 0 54 + 42 9 ± 22 south a s p e c t Yes 1400 80 ± 23 3 + 4 76 + 31 0 0 12 + 23 0 Yes 1800 75 ± 1 5 <1 0 0 0 8 + 2 1 < 1 Unsure 1 100 55 ± 1 1 30 + 30 16 + 26 0 0 20 + 2 7 10 ± 1 5 Yes 1000 70 ± 15 40 + 24 0 0 0 4 + 9 0 Unsure 700 60 ± 20 35 + 2 7 0 0 0 18 + 25 0 . No 3600 45 ± 20 56 + 26 0 6 + 10 0 0 8 4 ± 8 No 3000 50 ± 25 78 + 32 0 2 + 5 0 3 + 9 ± 1 1 No 2900 75 ± 19 52 + 35 0 0 0 4 + 8 9 ± 14 Mature t i m b e r ; No 1600 70 ± 13 31 + 23 1 0 0 2 + 5 18 ± 19 n o r t h a s p e c t Yes 1200 65 ± 13 1 + 2 0 0 0 10 + 1 7 0 No 1500 60 ± 10 2 7 + 2 7 0 0 0 34 + 39 5 ± 1 1 Yes 1500 10 ± 1 5 2 7 + 16 0 1 0 23 + 30 4 ± 7 T a b l e 1 Percent p l a n t cover on the permanent t r a c k count p l o t s a s measured in t h e autumn o f 1972 (mean ± S t . d e v . ) 1 / I n d i c a t e s whether o r not t h i s a r e a was used a s a w i n t e r range d u r i n g t h e s e v e r e w i n t e r o f 1 9 7 1 - 7 2 . 2 / Red cedar and y e l l o w c e d a r . Each v a l u e i s the mean o f 20 s u b p l o t samples. 1 8 from 3 tc 40%. Because cf the high variation within types, troad serai types cannot be used to predict vegetation ccver. The habitat classification system used dees ret adeguately explain the variation in the vegetation data. There is as much variation within habitat types defined by elevation, aspect, and serai type as there is between these habitat types (Table 1). Given that vegetation influences deer-use, it follows that deer-use of these habitat types will vary a great deal. 4.3 Winter and spring feed habits To understand deer ecology, one must knew the factors influencing deer nutrition. In this study, severe wirter weather had a definite effect upcc the diet cf the deer, 4.3.1 Food habits during the severe winter of 1971-72 During the severe winter deer ate mostly conifer and shrub material (Figure 5). The only food types occurring ic ncre than 50% of the samples were ccnifers, shrubs, and lichers (Figure 6) . Red cedar, salal, Dcuglas fir ana western hemlock each contributed more than 10? to the total vcluie eaten; and ncre red cedar and salal was eaten than any other plant species (Figure 7) . The only species occurring in more than 50* of the samples were red cedar, Douglas fir, western hemlcck, salal, and Vaccinium species (Figure 8). The food habits during early spring were different frcm the food habits during winter. Deer ate less conifer material and 19 mora forb, fern, and lichen material, but the ancunt cf shrub material in the diet retrained constant. All 6 food types occurred in more than 5CS of the samples in early spring, but only 3 food types occurred in more than 50% of the sanples frcm winter. The species shewing the greatest increases in volume from winter to spring were deer fern, Alectcria species, bunchberry, and grasses. Bed cedar, salal, and Alectcria species each contributed more than 10* to the total vcluae eaten in spring. The species occurring in more than one half cf the samples in early spring were red cedar, salal, deer fern, Douglas f i r , western hemlock, Vacciniura species, bunchberry, grasses, Alectoria species, and lebaria species (a foliose lichen) . 4.3.2 Food habits during the mild winter of 1972-73 During the mild winter, deer ate mostly conifers, shrubs, and ferns. A greater volume cf fcrbs and lichens was eaten during the mild winter than during the severe winter. The feed types occurring in more than 50% cf the samples were conifers, shrubs, forbs, ferns, and lichens. Deer fern and red cedar each contributed more than 1051 to the total volume eaten. Henlcck and Douglas fir were less heavily used during the aild winter than during the severe winter, suggesting that they were utilized when more palatable species were difficult tc obtain. The following species occurred in more than 50* of the saitples: red cedar, western henlcck, salal, deer fern, Vaccinium species, bunchberry, twinflower, Rubus species, and Polysticbua species (a fern) . F i g u r e 5 P e r c e n t volume o f the food types in the rumen samples 2 3 h 5 6 7 Con i f e r P = 0 .003 Shrubs P = 0 . 9 1 1 Forbs P = 0 . 0 3 6 F e r n s P = 0 . 0 0 1 L i c h e n s P = 0 . 0 2 8 Mosses L i v e r w o r t s M i s c 20a JANUARY 1 9 7 2 1 2 3 4 5 6 7 8 JANUARY 1 9 7 3 N: 15 1 2 3 4 5 6 7 8 MARCH 1 9 7 2 N:25 1 2 3 4 5 6 7 8 MARCH 1 9 7 3 N : 13 1 2 3 4 5 6 7 8 Figure 6 Percent occurrence of the food types in the rumen sampl FOOD TYPE 1 Conifers 2 Shrubs 3 Forbs 4 Ferns 5 Lichens 6 Mosses 7 Liverworts 8 Misc 100-JANUARY 1 9 7 2 B MARCH 1 9 7 2 LJJ O z uu C£ CC D O O O 1 2 3 4 5 6 7 8 C JANUARY 1 9 7 3 1 2 3 4 5 6 7 D MARCH 1 9 7 3 N :13 1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 22 Figure 7 Percent volume of the species in the rumen samples 1 Red cedar P = 0.047 2 Salal P = 0.294 3 Deer fern P = 0.001 4 Douglas-fi r P = 0.055 5 Twinflower P = 0.003 6 Hemlock P = 0.044 7 Alectoria sp P = 0.348 8 Vaccinium P = 0.524 9 Bunchberry P = 0.075 10 Rubus sp P = 0.056 11 Grasses P = 0.041 and the sta rp'e w a s c a , c u , a t e d 22a 100-80-60-40 100 80 60 40H 20 JANUARY 1972 n:15 B MARCH 1 9 7 2 n:25 1 2 3 4 5 6 7 8 9 10 11 C JANUARY 1 9 7 3 n : 1 5 1 2 3 4 5 6 7 8 9 10 11 D MARCH 1 9 7 3 n : 1 3 1 2 3 4 5 6 7 8 9 10 11 1 2 3 4 5 6 7 8 9 10 11 Figure 8 Percent occurrence of the species in the rumen sampl 1 Red cedar 2 Salal 3 Deer fern i. Douglas-fir 5 Twin flower 6 Hemlock 7 Alectoria sp 8 Vaccin i urn 9 Bunchberry 10 Rubus sp 11 Grasses 23a a* LU O z LU ir cc D o o o JANUARY 1972 n :15 B MARCH 1972 n : 2 5 1 2 3 4 5 6 7 8 9 10 11 C JANUARY 1973 n:15 1 2 3 4 5 6 7 8 9 10 11 D MARCH 1973 n : l 3 100 80": 60-; 40-1 20-f I BFWVM E 1 f 1 1 2 3 4 5 6 7 8 9 10 11 1 2 3 4 5 6 7 8 9 10 11 2 4 Although the food habits during early spring were similar to the food habits during the mild winter, deer ate nuch less deer fern in spring than in"winter. Cf the species occurring in more than 505! of the winter samples, cnly twinflower and Butus sp failed to occur in at least 50?! of the samples from early Spring. 4.3.3 Summary and discussion The data indicate that severe winter conditions limit the availability of many plant species to deer. In the severe winter, most of the diet was conifers and shrubs, but in the mild winter, conifers, shrubs, forts, ferns, and lichens were used. In the severe winter, 5 species occurred in more than 50$ of the samples, whereas in the mild winter 9 species occurred in more than 50% of the samples. Mere species were u t i l i 2 e d in winter than in spring, which again suggests that winter conditions restrict food availability to deer. Some of the conclusions from the food habits data differ from those based upen subjective field observations of deer food habits. The most important difference is in utilization cf lichens. Field observations suggest that arboreal lichens (principally Alectoria sarmentosa ) are much mere heavily utilized than shown in the data.. Cne reason that Alectcria was not more common in the rumen samples is that nest deer were collected in logged habitats, where A lectoria dees net cccur. However, because sone deer taken from legged habitats had been eating Alectcria , these deer must have done some feeding in 2 5 mature timber habitats. The data presented in the next section indicate that in winter, deer used mature timber habitats more heavily than logged habitats. In other areas CE Vancouver Island, arboreal lichens made available as litterfall comprised 343 and of the winter diet of deer (Cowan, 1945; Gates, 1968) . Future studies will probably show that deer in the Nimpkish Valley eat more lichen than was suggested in this study. 4.4 Winter habitat selection by deer 4.4.1 Habitat selection during the severe winter of 1971-72 During the severe winter fliuch snow lell from December through early M a r c h , and temporary track count plots were used to measure deer-use. The results show that deer-use cf mature timber and second-grcwth habitats was highly variable (Figure 9) , and deer-use indices taken from clear slash habitats (cn south aspects at low elevaticns) ranged from 0 tc S.4 (Appendix 4) . Deer generally used south aspects more than north aspects, and low elevations more than high elevaticns, but the differences were not consistent (Figure 9 and Appendix 4) . Much of the variation in deer-use of logged habitats was probably caused by differences in snow conditions. Few deer used logged habitats when the snow was deep and soft, but they used mature timber habitats where sues was' less deep. However, many deer used logged habitats when the snow became hard crusted. Figure 9 Range and median of the deer-use indices taken during the winter of 1971-72 The data presented in this figure were taken from south aspects Mature Timber TO TO T O 1500 2500 4000 E L E V A T I O N TO TO TO 1500 2500 4000 ( F T ) rv> cr\ SB 2 7 especially the second-grewth slash where the upper parts of shrubs and conifers were eaten. The deer-use indices from an area of second-growth were 0 and 2.3 when the sncw was soft, but when the snow became hard crusted the deer-use index increased to 24.6. The crusted snow conditions occurred for about 10 days out of the three-and-one-half-month winter period. During most cf the severe winter, deer made more use of mature timber habitats than logged habitats, apparently because snow was shallowest in the timber habitats (Figure 3). The most heavily used mature timber habitats were those having a dense crown closure, probably because snow depth is inversely related to crown closure (Figure 4). Cf the 19 permanent plots, 6 were in areas that deer csed extensively in the severe winter, and 11 were in areas that were used only slightly (Table 1). Five of the 6 plots used extensively during the first winter had 65% cr greater crown closure, and 1 had 60% crown closure. Cnly 2 of the plots that were used slightly had 655 or greater crown closure, and 1 of these plots was at 2900 ft elevation where snow was tee deep for deer. Also, 3 of the 5 temporary plots located during the mild winter (at elevations of 3400 ft cr greater) had 65* or greater crown closure, and 2 of these were used extensively by deer. None of the plots having less than 65* crown closure were used extensively. From these data, I conclude that in general, only habitats having 6535 or greater crown closure are suitable for winter range habitats when there is much snowfall. The results indicate that habitat selection is variable, 2 8 and depends upon more than elevation, aspect, and serai tspe. Field observations suggested that snow depth, snow hardness, crown closure, and food availability had more influence upon habitat selection than serai type, elevation, cr aspect. The experimental design was aedified befcre the second winter of study to determine if habitat selection was clcsely related to these variables. 4.4.2 Habitat selection during the mild winter of 1972-73 The habitat classification scheme was expanded in the second year of study to include the following habitat types: 1) mature timber having a shrub understory, 2) mature timber having a conifer understory. The predominant understcry species in the conifer understory timber types were western hemlock and Abies species, and the predominant understory species in the shrub understcry types were salal and Vaccinium species. When snow was present, I used the permanent track ccunt plots to measure deer-use, and when snow was absent, I counted deer to measure deer-use. Because of .the unusually light sncw conditions little useful information was collected from the pernanent track ccunt plots, and several assumptions were made when the data were analysed: 1) when there were no deer tracks on a plct, I estimated 2 9 the track depth frcm measured track depths taken from similar plots, 2) to take advantage of sporadic snowfall, I saved time ty not measuring vegetation if the snow depth was similar to the snow depth at the previous sampling date. It was assumed that the vegetation cover on the plot was identical to the cover at the previous sanplirg date. 4.4.2.1 selection of logged versus unloaged hatitats In the mild winter, habitat selection ty deer was apparently not correlated with elevation, crown closure, the estimate of lichen abundance, snow depth, or percent cover cf food plant species (Table 2). The track count indices were also poorly correlated with serai type (Table 2 ) , which suggests that deer made equal use of all serai types. This suggestion is incorrect, however, because many of the permanent plcts in timber habitats were located in areas that were used heavily ty deer during the severe winter of 1971-72. During the mild winter, deer made light use cf these areas, and they made more use of neighbouring mature timber habitats at high elevations. The data taken by counting deer in the daytime shew that in winter, deer made mere use of mature timber habitats than of logged habitats (Table 3). The mean deer-use index frca December through March was 2.1 in all timber hatitats, and 1.5 in all logged habitats. During April, deer made more use of the logged habitats than of the mature timber habitats (Table 3). T i m b e r , above A l l h a b i t a t s 3100 f t . o n l y E l e v a t ion S e r a i t y p e Crown c l o s u r e L i c h e n e s t . Snow depth T r a c k depth 2/ P e r c e n t c o v e r food s p e c i e s n = 30 n = 9 e 2 C o r r e l a t i o n s of t h e d e e r - u s e i n d i c e s w i t h o t h e r h a b i t a t measures taken d u r i n g t h e w i n t e r o f 1 9 7 2 - 73-These data were taken from t h e permanent t r a c k count p l o t s 1 / Spearman rank c o r r e l a t i o n . 2 / T o t a l c o v e r o f Vacc incum s p e c i e s , s a l a l , deer f e r n , western hemlock, c e d a r , and Douglas f i r . These data were c o l l e c t e d from t h e permanent t r a c k c o u n t s p l o t s . 0 . 1 7 0 . 1 3 0.24 0.22 -0.18 0.06 -0.08 0 . 5 3 0 . 3 6 - 0 . 5 1 -0.10 - 0 . 2 9 31 Mature t i m b e r Compare h a b i t a t P e r i o d Logged h a b i t a t s h a b i t a t s types December t o 1 . 5 ± 2 . 1 2 . 1 ± 1 . 8 H = 4 . 0 7 March n = 24 n = 38 p = 0.044 A p r i l 2 3 . 5 ± 5 3 . 3 n = 9 1 . 3 ± 1 - £ n = 1 3 H = 6 . 1 8 p = 0 . 0 1 3 T a b l e 3 D e e r - u s e o f logged and mature t i m b e r h a b i t a t s d u r i n g t h e w i n t e r and s p r i n g o f 1 9 7 2 - 7 3 (mean ± s t . d e v . ) . These i n d i c e s a r e c a l c u l a t e d from t h e d a y t i m e deer counts a s deer seen per 100 minutes o f s e a r c h i n g t i m e Each d a y ' s count i s c o n s i d e r e d as one index o f d e e r - u s e , and a l l s t a t i s t i c s a r e c a l c u l a t e d w i t h each d a i l y index used as one sample. The s t a t i s t i c s a r e c a l c u l a t e d w i t h t h e K r u s k a l - W a l 1 i s H t e s t . Shrub C o n i f e r Compare h a b i t a t P e r i o d u n d e r s t o r y u n d e r s t o r y types December to 2 . 8 ± 1 . 9 1 - 1 ± 1 - 0 H « 9 . 1 9 March n = 2k n = U p = 0.002 A p r i l 0.9 ± 0 . 8 2.0 ±2 . 8 H = 0 . 3 5 n = 8 n = 5 p = 0 . 5 5 3 T a b l e k D e e r - u s e o f mature t imber h a b i t a t s having a shrub u n d e r s t o r y and a c o n i f e r u n d e r s t o r y , dur ing the w i n t e r and s p r i n g o f 1 9 7 2 - 7 3 (mean ± s t . d e v . ) . The d e e r - u s e i n d i c e s and the s t a t i s t i c s a r e c a l c u l a a s e x p l a i n e d i n T a b l e 3. 33 4.4.2.2 selection of mature timber habitats During the mild winter, deer made more use of tinber hatitats having a shrub understory than those having a conifer understory (Table 4). The shrub understory habitats fcere probably preferred because they provided more browse than the hatitats having a conifer understory. The track count indices from mature timber habitats (3400 ft elevation or greater) were poorly correlated with elevation, track depth, and percent cover cf feed species (Table 2) . Eeer-use of the high elevation timber habitats was positively correlated with the estimate of lichen litterfall, although the correlation coefficient was low. Use of the high-elevation timber habitats was also positively correlated with crown closure and negatively correlated with snow-depth (Table 2). Many deer wintered in mature timber habitats at high elevations where sncw was present and browse scarce (Figures 10 and 11). I feel that these deer wintered as high it elevation as conditions permitted, and subjective observations suggest that Alectoria litterfall was a heavily used food item on the high elevation winter ranges. Scst high elevation areas that were heavily used by deer had shallow snow and high crcwn closure (Figures 10 and 11). 4.4.2.3 selection cf legged habitats The data taken by counting deer at night shew that deer made little use of clear slash hatitats in January, and the 54 Figure 10 Location of the track count plots.on Mt. Cain Plot number 1 2 3 k Elevation (ft.) 3800 3600 3000 1500 Location 5 was a heavily C>*own closure 10% kK% 50% 8n9r w -w (j used r a n n Q r l i i f - T n r i Deer-use 0 0 0 0 the mild winter of 1972-73. Snow-depth (ft.) 1.2 3.2 1.8 0.5 This area was not sampled % cover of n <11 19% 2% with plots. Vaccinium sp 34a MILES (HORIZONTAL DISTANCE) 35 Figure 11 Location of the track count plots on Abel Ridge Elevation (ft.) Crown closure Deer-use Snow-depth (ft.) Track-depth (ft.) % cover of Vaccinium sp Plot number 1 2 3 3900 3700 1800 35% 65% 15% 0-5 •6.6 1.2 3.5 0.8 0.6 0.4 0.4 -0 U <n Location 4 was a heavily used winter range during the mild-winter of 1972-73. This area was not sampled with plots. 35a 5000 _ C R O W N C L O S U R E ^ 6 5 % C R O W N C L O S U R E ^ 6 5 % 4000. 3000-I ^ 2000 _ UJ 1000. T H E FIGURE IS A C R O S S SECTION O F T H E MOUNTAIN O N W H I C H T H E P L O T S W E R E L O C A T E D . T H E N U M B E R S INDICATE PLOT LOCATIONS T" 3 ~r 4 M I L E S (HORIZONTAL DISTANCE) 3 6 intensity of use increased linearly from January through mid-May (Figure 12). The data points shown are the mean values cf the individual counts taken during each sampling period. Because deer did not make equal use cf all clear slash areas, only 32* of the variation in individual deer-use indices was explained by the time variable. In areas where large numbers cf deer wintered in the mature timber habitats, use cf neighbouring logged areas did not increase linearly from January through April. The rate cf increase of deer-use was greater in flarch and April than in January and February (Figure 13). In early spring, heavily used aeer trails led downhill from the high elevation winter ranges to the logged spring ranges. Deer-use of clear slashes did net continue to increase after mid-May of 1973 (Bochelle, pers. comm.) . 4.4.2.4 effect of snow on deer-use of a legged habitat In mid-March of 1973 there was a brief period wher abcut 10 inches of snow fell at 1000 ft elevation. When the roads were passable near the end cf the sncw period, I counted deer at night. The results indicate that the siow caused deer tc make less use of the clear slash habitats (Figure 14). In some areas most of the deer that were seen were on the border of the timber and the logged habitats. 4.4.3 Characteristics of winter range habitats The data are net sufficient to describe winter range Figure 12 Deer-use of clear slash habitats during the winter and spring of 1972-73 The deer use index is calculated as the number of deer seen at night per mile of road. The data points shown are the mean values of all counts done within each sampling period but the statistics are calculated with the individual deer-use indices (n= 107) The independent variable was 'day', with January 1 equal to '1' and May 17 equal to '137' 37a 25 -i 20 15 -10 -5 -Y : 0.75 + 0.17X R 2: 0.317 —r~ 20 I 40 T I 60 I 80 i 100 T 1120 I Jan i Feb i March i April • May - T — | R — 140 I 160 l I Figure 13 Deer-use of two clear slash areas during the winter and spring of 1972-73 Each data point represents the number of deer counted each night the transect was sampled 38a 80 A. Mt.Cain Road Test of common slopes F: 10.12 P: 0.013 60 -40 Y:-21.09+0.49X I -X o 2 20 cc LU CL Q UJ H-Z D O O 80 C£ m uj 60 40 -20 -i—r 20 • 40 '60 80 » 100 |120 140 | 160 Jan ! Feb ! March i Apri! : May : B. Abel Ridge Road Y:-36.56+0.91*^  Test of common slopes: fs 6.33 P: 0.032 20 • 40 1 1 ' - •. Jan i Feb i March i April i May F i g u r e 14 Effect of snow on deer-use of a clear slash area during the winter of 1972-73 Each data point represents the number of deer counted each time the transect was sampled The intervals shown are 95% confidence intervals of the proportion P, where P - Ni / Nt Ni = deer counted at each sampling Nt = total deer counted over all samplings 39a I-I <J 80-' 9 5 % CONFIDENCE INTERVAL DATE 4 0 „ sf-jt.^- , r f • a-f 1 J ' ' ^ ^ _ 4 » habitats quantitatively. However, subjective evaluations alien me to describe the characteristics typical of deer winter range in the Nimpkish study area. I realize that more detailed work is necessary to quantify the relationships expressed, and have presented these descriptions so that wildlife and forest managers can identify winter range habitats. Twc types cf winter range habitats are described: 1) habitats jsed during the severe winter, wher sncw was deep and soft, 2) habitats used during the mild winter, wher sncw was seldom present belcw 2500 ft elevation. 4.4.3.1 habitats used during the severe winter During the severe winter, mcst aeer used mature timber habitats at low elevations, and having shallow sncw. Some characteristics of the winter ranges were: 1) Crown closure: The habitats used heavily by deer during the winter cf 1971-72 had 65% or greater crown closure ^ (Table 1). White-tailed deer normally require winter f{ habitats having a crown closure of 70*, although in seme habitat types 45$ is sufficient (Gill, 1957). The most important effect of crown 'closure is the reduction of snow accumulation on the ground. In the Nitpkish, sncw in the mature timber habitats was about one-half as deep as snow in the logged habitats. Some heavily used winter ranges in mature timber on the valley bottom had low 41 crown closure (40 to 503 est.). Such areas were snail patches of timber surrounded by logged habitats. Subjective observations suggested that mortality was very high in such areas, and therefore such patches cf timber are probably not gccd winter range. 2) Food: The most important food items in the mature timber habitats were red cedar, Douglas fir, salal, Vaccinium species, arboreal lichens, and western hemlock (Figures 7 and 8). lichens, red cedar, and Douglas fir were made available as litterfall. 3) serai type: All heavily used winter ranges were mature timber habitats. However, not all mature timber habitats were winter range. The most important characteristic cf the winter range habitats was a high crown closure, logged habitats were used when the srcw was hard crusted. 4) Timber type: flcst heavily used winter ranges had Douglas fir and western hemlock in the cverstory. Timber habitats having cedar species or Abies species abundant in the overstcry were normally net used. The importance of timber type was its effect on crown closure. Douglas fir and hemlock types usually had higher crcwn closure than did types having abundant Abies species or cedar species. 5) Bock bluffs: Some heavily used winter ranges had exposed rock bluffs under the forest canopy. Such bluffs were often free of snow, and often had food available. However, some heavily used winter ranges did net have exposed rock bluffs. The crcwn closure was very low in some areas having exposed rock bluffs and therefore sncw was deeper. Deer use was lew in such areas. In general, areas having small bluffs were mere heavily used than areas having large bluffs. 6) Slope: Many winter ranges were on slopes steeper than 50X, and snow was often shallower on steep slopes than on valley bottom or ridgetop areas. The relationship cf snow depth with slope was not consistent in all areas visited. 7) Elevation: Mcst winter ranges were below 2500 feet elevation. However, elevation itself was not an important factor. The most important factor affecting habitat selection was sncw depth, and elevation was only one of several variables affecting snow depth. 8) Aspect: Many winter ranges sere on south aspects. North slope areas having a high crown closure and relatively high food abundance were used by deer. Scuth slope areas having low crcwn closure were not used by deer. In an earlier study, 16? cf white-tailed deer winter ranges were found on north, east, or northwest aspects, and it was uncertain whether aspect or vegetation type was the important factor influencing habitat selection (Webb, 1948). 4.4.3.2 habitats used during the mild winter Deer were observed in all habitat types during the itild winter. However, deer did not make equal use of all habitat 43 types. Some characteristics of the hatitats, that were heavily used are: 1) Crown closure: Most heavily used timber habitats had 65* or lower (estimate) crown closure. Hcwever, soire high elevation winter ranges had crown closure greater than 65%. High crcwn closure was important at high elevations because of greater snowfall. In general, areas having lew crcwn closure had greater feed abundance. Because of low snowfall, a dense crown closure was not necessary at mcst elevaticrs. 2) Food: The most important food items during the Bild winter were red cedar, salal, Vaccinium species, arboreal lichens, deer f e r n , bunchberry, and tvinflcwer. 3) Serai type: Many deer wintered in timber habitats having high abundance cf salal, Vacciniun s p , and Alectcria sp. Some deer wintered in second-growth slash habitats having high abundance cf red cedar, Vaccinium sp, and salal. In mcst areas, deer used logged habitats heavily only in the spring. 4) Timber type: Most timber hatitats that deer used extensively had auch Dcuglas fir and western henlcck, cr mountain hemlock, in the cverstory. In some areas, habitats having predominantly Abies species and cedar species in the cverstory were heavily used. The composition cf the overstcry probably had less effect on habitat selection than the composition cf the understory. 5) Bock bluffs: Mature timber areas having exposed reck bluffs were cften used heavily by deer. Such areas often had high abundance of s a l a l , Vaccinium species and arboreal lichens. Hhen soft snow was deeper than one foot on the areas having bluffs, deer moved tc habitats having a dense crcwn closure where snow was less deep. 6) Slope: Many timber winter ranges were in areas having steep (greater than 505 est.) slopes. Such areas generally had mere exposed reek bluffs than less steep areas. However, in many areas, deer made extensive use of flat-topped ridges. The relationship of deer-use with slope was inconsistent between different areas. 7) Elevation: Many winter ranges were at elevaticns greater than 250C feet. High elevation winter ranges were usually on south slopes and had high crcwn closures, and feed was scarcer in comparison with many low elevation habitats. Some deer ireved tc lewer elevations when fresh snow was more than cce feet deep and some remained high until the snow melted, 8) Aspect: Deer did not appear to consistently chccse any single aspect, and fcod abundance, snow, and tepegraphy apparently had the greatest effect upon habitat selection. 4.5 Movements of deer The radio-location data are insufficiently detailed to show accurately the home range size of the deer. However, I have specified the maximum amount of area that the deer used during 4 5 the winter period. In both cases, the maximum area was approximately one-quarter square mile (160 acres). One yearling female deer was tracked through the winter cf 1972-73. During winter, this deer used a mature timber area of less than 160 acres, on a south-facing slope at abcut 2000 ft elevation. On February 13 the deer was in a second-growth slash area at 1100 ft, and from February 15 to February 20 it was tack in the timbered winter range. In early March it moved to an adjacent clear slash area cf less than 160 acres. The deer was found in that area until May 25 when the radio signal was lost. A second yearling female d e e r , tagged in April of 1973, was tracked on its winter range from November 4 until February 8, 1974. Curing this period it used a 1200 ft elevation patch cf timber of less than 160 acres as its winter range. The limited data collected suggest that deer on their winter ranges move very little. Both cf the tagged deer used less than 160 acres as their winter range. Of the seven deer tracked later than May 1 of 1973, three moved from low elevation logged habitats tc high elevation mature timber habitats. These movements occurred in June, July, and September. In M a y , one deer moved from a low elevation logged area into a low elevation area cf mature tiaber. All cf these movements were longer than 1 mile. These results suggest that about one-half (4/7) cf the deer that use logged areas in spring move to unlogged areas in spring and surnrer. These observations agree with these cf Cowan (1956), who repcrted that T e s t e q u a l i t y o f ages Fawn Y e a r l i n g A d u l t (lumped sexes) ( i n c h e s ) ( i n c h e s ) ( i n c h e s ) Male 1 7 . 8 ± 1 . 0 ( 14) 2 0 . 9 ± 1 . 0 (5) 2 3 . 4 ± 1 . 2 (8) H = 4 3 . 0 4 5 p < 0 . 0 0 1 Female 1 7 - 5 ± 1 . 0 (9) 2 0 . 7 ± 1 . 0 (5) 2 0 . 9 ± 1 . 2 (25) t e s t e q u a l i t y H = 0 . 1 2 2 H = 0 . 4 0 H = 1 5 . 0 0 4 of sexes p = 0 . 7 3 P = 0 . 5 3 P < 0 . 0 0 1 T a b l e 5 Chest h e i g h t s o f deer (mean ± s t . d e v . ) . The sample s i z e i s in b r a c k e t s . 4 7 migrations from the spring ranges start in April cr M a y . 4.6 Chest heights of deer Old deer had greater chest heights than young deer, and male adult deer had greater chest heights than female adult deer (Table 5). There was no sex difference in chest heights cf fawn and yearling deer. The data suggest that deer will have a difficult time moving if they sink deeper than 17 to 23 inches in sncw. Adult deer will be able tc neve freely in deeper snow than will fawns, and male adults will be able tc move in deeper snow than will females. 4.7 Summary and discussion Snow is an important factor limiting the winter distribution of black-tailed deer (Edwards, 1956) , mule deer (Odocioleus hemionus heaignus^ (Halmo and G i l l , 1971), and white-tailed deer (Verme and Czaga, 1971). Where snowfall is heavy, all 3 deer species winter in habitats having the least snow. The ability of an animal to survive in deep snow will depend on its ability to move freely, and the ability tc move freely depends largely upon how deeply the animal sinks in the snow. The four most important factors governing hew deeply an animal sinks in sncw are chest height, snow depth, weight-loading on the hooves, and snow hardness. For example, moose 4 8 j A Ice s alcesj_ have greater chest height than vih ite-ta i led deer, and are able to winter in deeper snow than ate the deer (Kelsall, 1969). It is obvious that if the sinking depth in snow exceeds chest height for a long period, deer will have difficulty itcving in search of food. In the Nimpkish Valley, chest heights of deer averaged 17 to 23 inches, depending on sex and age (Table 5). In the severe winter of 1971-72, snow in the logged habitats at 1000 ft was about 4 ft deep fcr several months. This snow depth was much greater than the chest height of deer. Sncw in the mature timber habitats was about one-half as deep as sncw in the logged habitats (Figure 3 ) . Sncw was least deep in mature timber habitats having a high crown closure, but even in such habitats sncw mao cftsn sore than ess feet deep. Sncv in the timber was deep enough to cause hardship for deer, but snow in the logged habitats was deep enough to make deer-use impossible. When the deep sncw in the logged habitats formed a hard crust, deer made heavy use cf these areas. The tops of shrubs and conifers projected above the snow and were utilized during the period when the sncw was hard crusted. In the severe winter, the most important factor influencing use of logged habitats was not simple snow depth, but the combined effect cf sncw depth and snow hardness on deer sinking depth. In the mild winter, nany deer used mature timber habitats. Use of second-growth habitats was less intense than use cf the \ timber winter ranges, and this observation contradicts those of i Gates (1968). Gates found that because fcod was nest abundant in 49 12 to 15 year-old legged habitats in mid-central Vancouver Island, deer preferred to winter in these logged habitats. The different habitat selection patterns in the different areas are probably related to the different environmental conditions. Gates's study area has a generally milder winter climate and less snowfall than my study area. The area studied ty Gates is fairly level and has no steep mountains, whereas the Nimpkish area is flat only on the valley bottoms, and mcst cf the area is mountainous. In the Nimpkish a r e a , the timbered habitats that were used heavily by deer in the mild winter were usually on steep mountains. It is uncertain whether deer chose winter ranges having the greatest food abundance. Many deer wintered in high elevation timber habitats where browse was not abundant. The high elevation habitats had less browse than the second-growth habitats, but the second-growth was not used heavily during winter. However, mere deer used timber habitats having a shrub understory than used timber habitats having a ccnifer understory, probably because the shrub understory had more available food than the conifer understory. I feel that deer didn't always use habitats having the greatest feed abundance, but they used those habitats having adeguate food abundance. In Oregon, black-tailed deer often winter in habitats where tctal browse abundance is net the greatest available to the deer, and where the most palatable species are not abundant (Hines, 1973). The areas that were used heavily by deer during the severe winter were lightly used during the mild winter. Subjective 50 observations suggest that the habitats that were heavily used during the mild winter were the same as those used in autumn. The data on deer movements suggest that in suaner, irany deer move from the spring ranges at low elevations tc high elevation areas. I feel that the deer that make this movement are the same deer that use high elevation areas in mild winters. These deer will move to low elevation areas cnly if forced dcwn by deep sncw. Black-tailed deer (Dasmann and Taber, 1956), mule deer (Dixon, 1934; Russell, 1932) and white-tailed deer (Ccck and Hamilton, 1942; Severinghaus and Cheatum, 1956) cften use high elevation areas or summer range areas during mild winters. In the mild winter there were 2 major habitat types that were heavily used by deer: 1) mature timber habitats having exposed reek bluffs, high abundance of salal and Vaccinium species, and high abundance of Alectcria , 2) mature timber habitats above 2500 feet elevaticr, having high crown closure, high abundance of jlectoria , and low abundance of Vaccinium species. The pattern .of deer-use cf the logged habitats varied considerably between the two winters. In the severe winter, use of the logged habitats was lew except when sncw was hard-crusted. When the snow melted in April, many deer used the logged habitats. In the mild winter, use of the legged habitats was low in January and increased linearly through April. A brief 5 1 period of snow in March temporarily caused many deer tc step using the logged habitats. Subjective observations suggest that deer made extensive use of the logged habitats befcre the new year's growth of forbs had begun. Subjective observations of deer behaviour suggest that deer made heavy use of the logged habitats in April because these areas were the wariest. 4.8 Condition of deer In order to understand deer winter ecology, something should be known about the relationships between winter weather and the nutritional condition of deer. The kidney fat method was used tc estimate deer condition in late January cf 1972 and 1973, late Karch - early April of 1972 and 1973, and November cf 1972. The results are shown in Table 6 . The Kruskall-Wallis H test was used tc test fcr differences between the means of the different samples of deer condition. In all analyses discussed in section 4.8, fawns are deer less than 1 year eld, and adults are deer mere than 1 year old. More age classes would have been used had the sample sizes been larger. Probability values are given only when the results are significant at the 5^ level. I feel that the differences discussed in the text are real, even though not all of the differences are statistically significant. It is probable that more of the differences would have been significant if larger samples had been obtained. I was not able tc cbtaic complete data describing the condition of all age and sex classes cf deer. 52 4.8.1 Deer condition over the winters of 1971-72 and 1972-73 Within all age and sex classes cf deer for which comparable data are available (irale fawns, female fawns, female adults {p = 0.01)) , deer condition worsened during the severe winter cf 1971-72. All age and sex classes from which samples were taken (male fawns, male adults (p = 0.02) , female adults (p = 0.03) a'lso lost condition during the mild winter. All age and sex classes for which samples are available were in wcrse ccnditicn during the severe winter than during the mild winter (Table 6) . The linear regressions cf deer whole weight against deer eviserated weight are presented in Figure 15. The regression lines calculated for each winter cf the study have significantly different slopes (p = 0.024, which means that the average whole body weight for a given eviserated weight was greater in the severe winter than in the slid winter . Therefore, a greater proportion of whole body weight was muscle and fat in the mild winter than in the severe winter. This result suggests that deer were in better condition in the mild winter than in the severe winter. The difference in condition was greater fcr large deer (adults) than for small deer (fawns) . 4.8.2 Relationships between deer condition and the sex and age of deer In all sample pericds for which comparable data are available, female fawns were in better condition than male fawns (January of 1972, March of 1972, January of 1973); and female adults were in better condition than male adults (March cf 1972, P e r i o d Male Female Male Female fawn fawn a d u l t a d u l t J a n u a r y 1972 6 . 9 + 9 . 5 1 1 . ,5 + 2 . 7 - 4 3 . 1 + 2 4 . 0 n 5 n 3 n = 7 March 1972 1 . 2 + 3 . 3 3. .8 + 6. 0 2 . 8 + 5 . 0 8 . 7 + 9 . 0 n = 4 n = 5 n = 6 n = 1 1 November 1972 6 1 . 6 + 4 9 . 2 - 1 1 3 . 2 + 7 9 . 0 1 1 3 - 9 + 2 5 . 3 n = 3 n 3 n = 2 J a n u a r y 1973 9 . 2 + 3 . 7 18, ,4 + 9. 0 4 5 . 6 + 2 7 . 1 1 0 0 . 5 + 5 5 . 8 n — 3 n = 2 n = 3 n = 7 March 1973 8 . 2 + 1 . 0 - 1 1 . 0 + 6 . 4 4 1 . 2 + 3 0 . 5 n = 2 n = 6 n = 6 T a b l e 6 Deer c o n d i t i o n i n d i c e s (mean ± s t . d e v . ) -54 I F i g u r e 1 5 Regression of whole weight a g a i n s t e v i s e r a t e d weight 160-140 120-o" l _ 1 0 0 -£ L U 8 0 -_j 0 1 £ 60J 40-20-WINTER 1971-72 y-.0.97+1.57 x N s 41 WINTER 1972-73 ys 1.68 +1.37 X 20 40 60 80 100 20 40 60 80 100 EVISERATED W T (ibs) Test of Hypothesis of Common Slope F:5.21 P: 0.024 ® 55 January cf 1973, March cf 1973 (p = 0.01); (Table 6)).. In all sample periods, female fawns were in worse condtion than female adults (January of 1972 (p = 0.02), March cf 1972, January cf 1973 (p = 0.04)); and male fawns were in wcrse condition than male adults (March cf 1972, Kovember of 1972, January of 1973 (p = 0.05), March of 1973; (Table 6)). 4.8.3 Summary and discussion Deer condition deteriorated markedly during the severe winter cf 1971-72, probably because cf the severe weather. leer condition also deteriorated during the mild winter, but less than it did during the severe winter. Various authors have ncted that even when feed is abundant in a mild winter, deer voluntarily reduce their food intake and therefore lese up to 25% of their tody weight (Bandy, 1965; Czoga and Verme, 197C). In all sample periods, fawns were in worse condition than adults. Even in November of 1972, fawns had less bedy fat than adults. These results agree with all published studies cf black-tailed, mule or white-tailed deer (Anderson, Eedin, and Eowden, 1972; Bartlett, 1950; Eartlett, 1955; Brown, 1961; Einarsen, 1956; Erickson, Gunualson, stenlund, Burcalow and Blankenship, 1961; Lassen, Ferrel and Leach, 1952; Bobinette, Gashwiler, Low and Jones, 1957) . Fawns are less able to withstand severe winter weather than are yearlings or adults. The relative mortality rates of fawns and adults vary with the severity of winter. In general, the proportion of adults in the ircrtality increases with increasing severity of winter (Eartlett, 1955) 56 and with decreasing range condition (Klein and O l s c n , 1960). The data suggest that male deer were always in worse condition than fetrale deer. In most a r e a s , male b lack-tailed deer (Taber and Dasmann, 1954), mule deer (Robinette, Gashwiler, Low and Jones, 1957), and white-tailed deer (Bartlett, 1955) die at higher rates than females. H o w e v e r , some authors have found that female fawns sometimes die at higher rates than irale fawns. Robinette, Gashwiler, Lew, and Jones (1957) found that although adult male mule deer had the highest mortality rates, female fawns died at higher rates than male fawns. The results cf a previous study on Vancouver Island suggested that fesale fawns have higher mortality rates than male fawns (Smith, 1968). The results of this study, and some previous studies, indicate that when winter weather is severe, deer condition decreases rapidly and many deer diei The amount of condition that the deer l o s e , and the number of deer that die, are directly related to the severity of the winter (Severinghaus, 1947). In O n t a r i o , 46% of a herd of white-tailed deer died during a severe winter, but enly 6S died during a mild winter (Cumming and Walden, 1970). Fawns usually die at higher rates that adults, and males usually die at higher rates than females. 5 . DISCUSSION The following discussion synthesizes the results of this study with those of earlier workers, and is divided intc 3 sections: 5 7 1) Effects of winter weather, on deer 2) Ecological nechanisms mitigating the effects of winter weather on deer 3) Management reccffsrendations 5.1 Effects of winter wea ther on deer Various authors have reported that the severity cf winter weather, or the amount and quality of winter range, are important factors affecting population sizes of black-tailed, mule and white-tailed deer (Brown, 1961; EeNio, 1938; Edwards, 1956; Wallmo and Gill, 1971). The effect cf severe weather is to cause malnutrition and mortality. 5.1.1 Seiatioiiiiiifc-is between de<ii coalition, mortality rates, and winter weather In deep snow, deer have a hard time finding food (Coblectz, 1970; Moen, 1973) and moving about (Verme and Czoga, 1971; Wallmo and Gill, 1971) . The food plants available in winter are less nutritious than the herbaceous plants available in spring and summer (Gates, 1968). Move cent through deep snow is difficult and requires much energy (Verme and Czcga, 1971), and cold winds or low temperatures cause additional energy losses (Moen, 1 968a, 1 968b). Many authors have reported that deep snow in winter causes poor condition and heavy mortality of black-tailed, uule, and white-tailed deer. In western Washington, sncw depths cf 2 feet caused 25% to 30% of a black-tailed deer hard to die. Most of 58 the carcasses were found in clear slash hatitats (Brown, 1961). In California, a severe winter resulted in death of 35* of a mule deer herd and less cf 82* cf fawns (Iassen, Ferrel, and Leach, 1952). In another area of California, 4-fcct sr.cw depths resulted in death cf cne-third cf a mule deer herd and less cf almost all of the fawns (lecpcld, Biney, McCain, and Tevis, 1951). In Utah, snow depths of 2.5 to 3 feet resulted in the death of 42%, 26%, and 9% cf 3 mule deer herds, and the lesses were inversely related to the amount of available browse (Bobinette, Julander, Gashwiler, and Smith, 1952). fi severe winter caused the death of 63% of fawns, 19% cf adults, and 35% of a white-tailed deer herd (Bartlett, 1950). In other areas, severe winters caused mortality rates of 10 to 25% and 60% of 2 white-tailed deer herds (Irickson, Gunualscn, Stenlcnd, Burcalow, and Blankenship, 1961; Bartlett, 1955). It is clear that severe winters can cause extensive mortality of deer. Fawns and very old deer usually have higher mortality rates than prime age deer. Fawns probably die at high rates because they have less bedy fat in proportion to their weight than adults (Table 6). Fawns have less fat than adults because they have a fast rate of growth during their first su a iter cf life (Bandy, 1965). Fawns alsc have more difficulty than adults in deep snow because they have lower chest heights than adults (Table 5). Bales often die at higher rates than females, possibly because they lese more ccndition in late autumn. However, males have greater chest heights that females, indicating that they have less difficulty moving in deep sncw (Table 5). 59 5.1.2 Relationships between winter weather and deer reproduction I was not able to assess the effects cf winter weather on deer reproduction. However, previous authors have found that severe winters affect reproduction cf mule and white-tailed deer. Verme (1969) found that if white-tailed females are in poor condition during winter, they give birth to weak or stillborn fawns. Mule deer fawns born after a severe winter weighed 12% less than those born after a mild winter (Robinette, Gashwiler, Low, and Jcnes, 1957). There are fewer fawns per female following a severe winter than following a itild winter (Robinette, Gashwiler, L o w , and Jcnes, 1957; Verme, 1967). In California, the rates cf reproduction were negatively correlated with the degree of utilization of winter food (Dasmarn and Blaisdell, 1954). Apparently, severe winter weather causes greater prenatal and early mortality rates of males than females (Robinette, Gashwiler, Low, and Jones, 1957). Klein (1970) summarized the reasons why early mortality of newborn fawns increases after a severe winter: 1) the fawns are in poor condition, 2) the fawns are too small to reach the teats, 3) the female delays lactation, 4) the female will net allow the fawn to suckle. The effects of severe winter weather cn future reproduction depend partly upon the rate of early fawn mortality (Verme, 6 0 1969). If a female successfully raises fawns after a severe winter she must lactate all summer, tut if her fawns die she will not lactate all summer. These females that lactate during the summer may not be able to regain condition, and will have lower pregnancy rates the following autumn. Hcwever, these females that do not lactate guickly gain condition, and will probably have high productivity the following autumn. Poor condition of the summer range may also lower productivity the following autumn (Verme, 1969). 5.2 Ecological mechanisms mitigating the effects of winter weather on deer The preceeding discussicn shewed that severe winter weather • reduces deer survival and reproduction. The information discussed in the results indicated that deep S E C * is a majcr factor affecting deer. Severe cold also affects white-tailed (Hoen, 1968a and 1968b) and presumably black-tailed and uule deer. One adaptation tc winter weather is a reduction of metabolic rate (Silver, Colovos, Holter, and Hayes, 1969). Deer probably require less feed in winter than at other times cf the year, and black-tailed and white-tailed deer voluntarily reduce their food intake in winter (Bandy, 1965; Czcga ard Verme, 1970). The reduction in food intake is coincidental with the onset of mating acitivity (Bandy, 1965). The net effect of reduced food intake and reduced metabolic rate is weight loss and reduction of body fat reserves. Severe winter weather 61 increases the loss cf weight and f a t , as demonstrated in this study. In areas where winter is severe, deer alter habitat selection and activity patterns to reduce the effects of severe weather. In cold weather, white-tailed deer feed less (Czcga and Verme, 1970), but increase movements to sheltered habitats (Ozoga and Gysel, 1 972) . Deer confined tc cold habitats seek out ^ the warmest micro-climates (Robinson, 1960). Eeer ir peer condition feed more than deer in good condition (Ozoga and Verme, 1970). Many authors have demonstrated that deep snow makes movement difficult for deer, although sncw hardness is also important. Snow depths cf 18 inches (Gilbert, Walimo, and Gill, 1970) , 20 inches (Cumming and Salden, 1970; Telfer, 1970a; Severinghaus, 1947), 15 inches (Kelsall, 1969), 2C tc 24 inches (Loveless, 1967), and 24 inches (Miller, 1968) caused black-tailed, mule, and white-tailed deer tc concentrate. Snow depths of 24 to 36 inches (Russell, 1932), 4 tc 6 feet (Spiker, 1933), and 4 feet (Leopold, Riney, McCain, and Tevis, 1951) sere disastrous for mule and white-tailed deer. In all studies where snow depths greater than 20 inches were reported, deer moved to areas where sncw was less deep. In some areas, mule and black-tailed deer move to lower elevations where snow is very shallow or non-existent (Wallirc and Gill, 1971; Dasmann and Taber, 1956). In regiens where sncw is deep at all elevations, deer move to mature coniferous timber habitats where the dense canopy reduces sncw depth en the grcund 62 (Cumming and Walden, 1970; Edwards, 1956; , Kelsall and Prescott, 1971; Ozoga, 1968; Telfer, 1970a and 1970b; Verne, 1965). In Alaska, deer often winter on teaches at sea-level, where sncw is least deep (Klein and Clscn, 19 60). In Yellowstone Park, mule deer have been known to winter near hot springs at high elevations. Even though snowfall is heavy the heat frcm the hot springs keeps the grcund bare (Russell, 1932). White-tailed deer iE many areas have a behavioural pattern known as "yarding" (Spiker, 1933; Webb, 1948). A "yard" is typically an area where heavy cover is interspersed with open areas. The heavy cover provides shelter while the open areas provide food. Although snow is deep in the open areas, the deer maintain a network cf packed trails through the srev. Movement is difficult except on the packed trails (Verme and Czoga* 1971). A white-tailed deer winter concentration area is enly a true "yard" if it is a clearly defined area having a network cf packed trails (Webb, 1948) . Cover is the most important factor of a deer yard. £eer will not use an open area if coniferous timber cover is absent, but they will use an area where timber cover is present but feed scarce (Hamerstrom and Elake, 1939; Hosley, 1956; Webb, 1948). Gill (1957) suggested that winter shelter and food should be a maximum of 100 yards apart. The studies reviewed suggest that white-tailed deer and black-tailed deer in northern areas are subjected to severe winter snow conditions. Food and cover are separated in many areas used by white-tailed deer during winter, but the mature timber habitats used by black-tailed deer in the Kimpkish Valley 63 provide both food and shelter. My observations suggest that salal, Vaccinium species, and litterfall (red cedar, touglas fir and arboreal lichens) 'are the most important foods in the mature timber. Litterfall and windfall material is sometimes a significant source of winter food for black-tailed, mule and white-tailed deer (Cowan, 1945 and 1956; Dixon, 1934; Gates, 1968; Ozoga and Gysel, 1972; Spiker, 1933). In South Eakota, the amount of litterfall lichen JUsnea species) eaten by lule and white-tailed deer increases with increasing snow depth (Schneewis, Seversen, Petersen, Schenck, Linden, and Richardson, 1972) . In all areas where winter is severe and black-tailed, mule, or white-tailed deer cannot move to areas where snowfall is light, mature coniferous timber is necessary for winter shelter. However, deer in different areas choose different serai types for use during mild winters. Gates (1968) reported that on Vancouver Island, deer used 12 to 15-year old serai types in mild winters. In other areas, early serai types are the test winter ranges during mild winters (Brown, 1961; Taber, 1961). However, recently burned areas are peer winter range because the shrub communities are destroyed and there are few plants alive during winter (Interstate Deer Herd Committee, 1954). Use cf very early serai types is low in winter and increases in spring (Spiker, 1933). In the Nimpkish Valley, many deer used high elevation mature timber habitats in the mild winter, and use of logged habitats was low in January and increased through April (Figure 12). It appeared as if most deer remained as high in elevation as snow conditions permitted. In other areas, deer use 6 4 summer or autumn ranges during mild winters (Cumming and Walden, 1970; Dasmann and Taber, 1956) and deer in the Kimpkish Valley behave similarly. Deer-use of winter concentration areas is heavy only during severe snow or temperature conditions. This behaviour pattern results in the food plants on the critical winter ranges being h»eavily utilized only when necessary. 5.3 Management reccnmendaticns This study was intended to provide information useful in the management of deer in the mountainous, high stew regiens cf Vancouver Island. The fcllcwing recommendations should not be generalized to regions having climate or topography different from those of the Nimpkish Valley study area. The results and discussion shew that deer depend upon mature timber during severe winters. Logging relieves mature timber and therefore reduces winter range and deer populations. In the Nimpkish Valley, continuation cf previous logging methods will create extensive areas of early serai types with nc mature timber available for deer winter range. Therefore, the most important recommendation is that heavily used winter ranges be excluded from future logging plans. The results of the radic-tagging project suggest that at least one-half of the deer using low elevation logged habitats in spring move to high elevation mature tinter habitats in summer and fall. In winter, the deer remain in high elevation 6 5 mature timber habitats until forced to lew elevaticrs by scow, and possibly by ccld weather. In the Nimpkish Valley there is little logging above 3000 ft elevation, and when snow is shallow many deer winter in timber at this elevation. However, when snowfall is heavy the deer move to low elevation timber habitats. Observations suggest that deer move through mature timber habitats tc the low elevation winter ranges. If mature timber is not available for downhill movement, and if snow is deep in the logged habitats, many deer are forced tc remain at the lower edge of the high elevation timber. Therefore, I recommend that strips of mature timber be left extending from sub-alpine to the low elevation winter ranges. Such strips would be used as winter range during mild winters and as downhill movement routes during severe winters. Subjective observations suggest that such corridors should be a minimus cne-half irile in width. Hot all low elevation mature timber habitats are suitable for deer winter range. The most important characteristic cf timber winter range is a dense crcwn closure. The data taken from the permanent plots suggest that crown closure should be 65* or greater. White-tailed deer require timber having a minimum crown closure cf 45 tc 70S (Gill, 1957) or 5C* (Verme, 1965) , depending on forest type. When snowfall is heavy, the amount of shelter provided by a"habitat type determines which habitats are available for use by deer. Within the habitats available for their use, they will make, most use of those having the best food supply. I recommend that only those habitats having crown closures greater than 65* be left for deer winter 66 range. A more detailed list of the characteristics cf winter range was presented in section <4.4.3. It is uncertain hew much area is required for winter range, and much will depend on how many deer are desired in an area, cn the frequency of severe winters, and cn the number cf deer that a habitat can support, fly subjective observations suggest that good winter habitats may support up to 400 deer per square irile over a 3 to 4 month winter period, a figure consistent with some previous studies cf white-tailed deer (Davenport, Shapton, and G o w e r , 1944). Previous authors have stated that winter range occupies 10% (Cowan, 1950), 13% (DeNio, 1938), 7 tc 8%, 10 tc 13% (Severinghaus and Cheatum, 1956), and 5 to 155 (Telfer, 1970a) of a given region. If these figures are relevant to the • Sispkish Valley, then approximately 10% cf the area should be left as winter range. The guidelines given are general because any given valley is a separate case, and should be studied individually to determine a management plan. The guidelines relate to the current situation and state cf knowledge, and sill undoutedly be altered in the future. The necessity for cld-grcwth timber as winter range will decrease as new growth on logged areas matures. 6 7 REFERENCES Anderson, A.E., D . E . Madin and D.C. Bcwden. 1972. Indices of carcass fat in a Colorado mule deer population. J . Wildl. M g m t . 36: 579-594. Bandy, P . J . 1965.. A study of comparative growth in four races of black-tailed deer. Ph.D. Thesis, Oniv. Of British Columbia, Vancouver, 189 p. Bartlett, I.B. 1950. Michigan deer. Kich. Fept. Conserv., 50 p . Bartlett, C. 0. 1955. Starvation of deer on Navy Island. Ontario Department cf lands and Forests, Tech. Eull. N o . 5, 18 P* / Brown, E.R. 1961. The black-tailed deer of western Washington. Washington State Game Department Biol. Eull. Ko. 13, 124 P . 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The Deer of North America. The Stackpole Cc., Harrisbcrg, Penn., 668p. Interstate Deer Herd Committee. 1954. Eighth progress report cn the cooperative study of the Devil's Garden Interstate deer herd and its range. California Fish and Game 40 :235-266. Kelsall, J . P . 1969. Structural adaptations of moose and deer for snow. J. Mammal. 50:302-31 0. 70 Kelsall, J.P. and W. Prescott. 1971. Poose and deer behaviour in snow. Canadian Wildlife Report Series Nc. 15, 27 e. Klein, D.R. 1970. Feed selection by North American deer and their response tc over-utilization of preferred plant species, pp. 25-46, In, Watscn, A. (ed.). Animal Populations in Relation to their Feed Resources. Blackwell, Oxfcrd, 477p. Klein, D.R. and S.T. Olson. 1960. Natural mortality patterns cf deer in southeast Alaska. J . Wildl. Mgmt. 24: 80-88. Lassen, R.W., C . M . Ferrel and H.R. leach. 1952. Food habits productivity and condition of the Doyle osule deer herd. California Fish and Game 38:211-224. Leopold, A., T. R i n e y , R . McCain and 1. Tevis. 1551. The Jawbone deer herd. California Division cf Fish and Game Eull. No. 4 , 139 p. Loveless, C.M. 1967. Ecclcgical characteristics of mule deer winter range. Colorado Department of Gate, Fish and Parks Tech. Publ. Nc. 20, 124 p. Meiman, J . R . 1968. Sncw accumulation related to elevation, aspect and forest canopy. National Workshop Seffirar, Snow Hydrology, Feb. 28-29, 1968, Univ. Of Fredericton, New Brunswick, 2 0 p . Miller, F.L. 1968. Observed use of forage and plant ccnmunities by black-tailed deer. J. Wildl. Mgmt. 32:142-148. Moen, A.N. 1968a. Energy exchange of white-tailed deer, western Minnesota. Ecology 49:676-682. Moen, A.N. 1968b. Surface temperatures and radiant heat less from white-tailed deer. J. Wildl. ffgmt. 32 :338-343. 7 1 Moen, A.N. 1973. Wildlife Ecology. w.H. Freeirac 6 Cc., San Francisco, 478 p. Ozcga, J . J . 1968. Variations in microclimate in a conifer swamp deeryard in northern Michigan. J . Wildl. Mgmt. 32: 574-585. Ozcga, J.J. and L.W. Gysel. 1972. Response of white-tailed deer to winter weather. J. Wildl. Mgmt. 36:892-896. Ozoga, J.J. and C.J. Verme. 1970. Winter feedirg patterns cf penned white-tailed deer. J. Wildl. Mgmt. 34:431-439. Packee, E.G. 1972. The biogeoclimatic subzcnes cf Vancouver Island and the adjacent mainland and islards. Forest Research Note No 1. MacRillan Blcedel ltd. Hanaimo, E.C. Robinette, W.L., J.S. Gashwiler, J, low and E. A. Jctes. 1957. Differential mortality by sex and age among mule deer. J . Wildl. Mgmt. 21:1-16. R o b i n e t t e , W . L . , 0 . J u l a n d e r , J . S . G a s h w i l e r and J . G . S m i t h . 1952. Winter mortality of mule deer in Utah in relation to range conditions. J. Wildl. Mgmt. 16:269-2SS. R o b i n s o n , W.L. 196C. Test of s h e l t e r r e q u i r e m e n t s of penned w h i t e - t a i l e d d e e r . J . W i l d l . Mgmt. 24: 364- 371. Rochelle, J.A. Pers. ccmm. Ph.D. Candidate, Faculty of Forestry, Dniv. Of British Columbia. 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Regional Wildlife Biologist, British Columbia Fish and Wildlife Branch. Spiker, C.J. 1933. Some late winter and spring observations on the white-tailed deer of the Adirondacks. Rccsevelt Wildl. B u l l . 6:327-385. Taber, R . D . 1961. The black-tailed deer; a review of ecology and management. La Terre et la Vie 2:221-245. Tater, R.D. and R. F. Easmann. 1954. A sex difference in mortality in ycurg Columbian black-tailed deer. J. Wildl. Mgmt. 18:309-315. Telfer, E.S. 1970a. Relationships between logging and big game in eastern Canada. Pulp and Paper ("agazine of Canada, Oct., p. 69-74. Telfer, E.S. 1970b. Winter habitat selection by moose and white-7 3 tailed deer. J. Wildl. Wgint. 34: 553-559. Verme, L . J . 1965. Swamp ccnifer deer yards in northern Michigan, their ecology and nanagement. J. Forestry 63 :523-529. Verme, L.J. 1967. Influences of expericcental diets cn white-tailed deer reprcducticn. Trans. K. Am. Wildl. Conf. 32: 405-420. Verme, L.J. 1969. 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Thesis., Univ. of British Columbia, Vancouver, 164 p. 74 N 50 ft CENTRAL DEER TRACK A) Method o f measur ing deer use The a r e a under s t u d y was sampled w i t h 1 to 20 temporary t r a c k count p l o t s . The deer use index i s t h e t o t a l number o f t r a c k s c r o s s e d by a l l 4 f i f t y f o o t 1 i n e s . 150 FT '9 FT B) Method o f measur ing snow depth The snow depth measure i s t h e mean o f t h e 18 samples Appendix 1 Methods used to count deer t r a c k s and measure snow depths d u r i n g the w i n t e r o f 1 9 7 1 _ 7 2 . 100 FT -4 Design o f the permanent t r a c k count p l o t s used d u r i n g t h e w i n t e r o f 1 9 7 2 - 7 3 -The f i v e l i n e s were p a r a l l e l and were r o u g h l y p e r p e n d i c u l a r to the elevation contours, V e g e t a t i o n , snow depth, and crown c l o s u r e were a l l measured from t h e s u b p l o t s . T r a c k count and t r a c k depth measures were taken from the 50 f o o t l i n e s between s u b p l o t s . A l l l i n e a r and a r e a measures were taken a l o n g the ground s u r f a c e . No attempts were made to c o r r e c t f o r e f f e c t of s l o p e on h o r i z o n t a l , o r map, d i s t a n c e . L a b o r a t o r y : The c o n t e n t s of each j a r were p l a c e d i n t o a 0.1 -mm gauge n y l o n c l o t h and squeezed to e x t r a c t e x c e s s m o i s t u r e . The e n t i r e c o n t e n t s were then p l a c e d i n t o a graduated 500-ml beaker p a r t i a l l y p r e f i l l e d w i t h water in o r d e r t o d e t e r m i n e the t o t a l volume. The c o n t e n t s were then t h o r o u g h l y washed w i t h tap water through number 3i and number 5 s i e v e s ( 5 . 6 6 and 4 . 0 0 mm). The c o n t e n t s r e m a i n i n g on t h e s c r e e n s were washed i n t o a w h i t e p o r c e l a i n d i s h and s e p a r a t e d w i t h t h e a i d o f f o r c e p s . Each p l a n t s p e c i e s o f each sample was then p l a c e d i n t o t h e n y l o n c l o t h and a l l e x c e s s m o i s t u r e was squeezed o u t . Measurements o f a l l samples 1 . 0 ml and o v e r were done by p l a c i n g t h e moist m a t e r i a l i n t o a 2 5 0 - m l . graduated c y l i n d e r p a r t i a l l y p r e f i l l e d w i t h w a t e r . The v o l u m e t r i c d i s p l a c e m e n t o f a l l s p e c i e s under 1 . 0 m l . was done by o c c u l a r e s t i m a t i o n w i t h f r e q u e n t c h e c k s f o r a c c u r a c y u t i l i z i n g a 1 0 0 - m l . graduated c y l i n d e r . Note: In the event t h a t p l a n t s were not i d e n t i f i a b l e as to s p e c i e s , t h e volume o f t h e v a r i o u s r e c o g n i z a b l e rumen components were measured and p l a c e d i n t o coded s e p a r a t e p l a s t i c bags t o g e t h e r w i t h a s m a l l amount o f 10 p e r c e n t f o r m a l i n . Appendix 3 Method used to a n a l y s e the deer rumen samples. The d e s c r i p t i o n o f t h e method used to a n a l y z e the rumen samples was p r o v i d e d by the F i s h and W i l d l i f e Branch. 77 S e r a i t y p e E l e v a t i o n Second growth ( f t . ) C l e a r s l a s h s l a s h Mature t imber 500 to 1500 0 , 8 . 4 , 9 . 4 0, 2 . 3 , 2 4 . 6 3 . 5 , 3 - 7 , 4 . 1 , 4 . 3 , 4 . 7 , 9 . 9 , 1 4 . 1 , 1 6 . 6 1500 to 0 0 , 2 . 0 2 . 8 , 4 . 6 , 9 . 2 , 2500 9 - 3 , 1 5 . 2 South a s p e c t 2500 to 0 no d a t a U, 2 . 2 , 2 . 8 , 4000 2 . 8 500 to 1500 0 , 7 . 0 no d a t a 0, 1 . 5 , 1 . 5 , 4 . 0 1500 t o 0 no d a t a 0 , 1 . 6 , 2 . 2 , 2500 2 . 2 , 4 . 5 North a s p e c t 2500 to no d a t a no d a t a 0 , 0 . 8 4000 Appendix 4 Summary o f the t r a c k count data taken d u r i n g the w i n t e r o f 1 9 7 1 - 7 2 . The d a t a presented were c o l l e c t e d under a l l snow c o n d i t i o n s . Zero deer use i n d i c e s were taken many t i m e s in t h e logged h a b i t a t s , however, o n l y one z e r o v a l u e i s g i v e n f o r each logged h a b i t a t . Common name B o t a n i c a l name Red cedar Y e l l o w c e d a r ( c y p r e s s ) Douglas f i r Western hemlock Mount? in hemlock T r u e f i r S a l a l Bunchberry T w i n f l o w e r Deer f e r n T h u j a p l i c a t a Chamaecypar is nootkatens Pseudotsuga menzi es i i Tsuga h e t e r o p h y l l a Tsuga m e r t e n s i a n a A b i e s sp. G a u l t h e r i a s h a l I o n Cornus c a n a d e n s i s L i n n a e a b o r e a l i s Blechnum s p i c a n t Appendix 5 B o t a n i c a l names o f t h e p l a n t s p e c i e s d i s c u s s e d in t h e t e x t . 

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