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Survival and Winter Diet of Sylvilagus obscurus (Appalachian Cottontail) at Dolly Sods, West Virginia
Alana C. Hartman and Ronald E. Barry

Northeastern Naturalist, Volume 17, Issue 3 (2010): 505–516

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2010 NORTHEASTERN NATURALIST 17(3):505–516 Survival and Winter Diet of Sylvilagus obscurus (Appalachian Cottontail) at Dolly Sods, West Virginia Alana C. Hartman1,* and Ronald E. Barry2 Abstract - The distribution of Sylvilagus obscurus (Appalachian Cottontail) is disjunct and restricted to high-elevation refuges in the central and southern Appalachian Mountains. The purpose of this study was to determine survival and winter diet of this rabbit at its type locality, the Dolly Sods area of the Monongahela National Forest, WV. To estimate survival, 44 Appalachian Cottontail individuals were radio-tracked until death or loss of transmitter signal between October 1997 and June 2000. The Kaplan-Meier estimate was used to generate finite survival rates. To assess winter diet, stems browsed within a 1-m radius of winter radiolocations of 15 individuals in 1998–1999 and 1999–2000 were identified and counted. Species and groups of species browsed were compared to availability, determined by counting the number of woody stems within a 1-m radius of the same radiolocations. Overall daily survival rate was 0.9934, finite monthly (28-day) survival rate was 0.8309, and finite yearly survival rate was 0.0894. No differences in survival were found between sexes or age groups. The first leaf-off season had lower daily survival rates than those of the subsequent leaf-on and leaf-off seasons. Gaultheria procumbens (Eastern Teaberry), Vaccinium spp. (blueberries), Gaylussacia baccata (Black Huckleberry), and Photinia spp. (chokeberries) were preferred winter browse. Rhododendron spp. and the abundant Kalmia latifolia (Mountain Laurel) were consumed less than expected. Introduction The group of cottontails once considered to comprise the species Sylvilagus transitionalis Bangs (New England Cottontail) consists of 2 distinct cytotypes (Ruedas et al. 1989). On the basis of morphometric data, Chapman et al. (1992) recognized 1 of the cytotypes, the population southwest of the Hudson River, as S. obscurus Chapman, Cramer, Deppenaar, and Robinson (Appalachian Cottontail). This taxon has a limited distribution within the Appalachian Mountain range, from central and eastern Pennsylvania to northwestern Georgia and north-central Alabama, where it occurs at high elevations in a mosaic of refugial relicts (Chapman and Stauffer 1981, Chapman et al. 1982). In West Virginia, it is designated an S3 species (only 21–100 documented occurrences; West Virginia Natural Heritage Program 2007). Cottontail survival may relate to abundance and distribution of cover, especially in winter (Trent and Rongstad 1974). Predation is the primary mortality factor for cottontails (Boland and Litvaitis 2008, Chapman et al. 1982), and previous studies have documented mammalian and avian predators of Appalachian Cottontails (Barry et al. 1997, Sommer 1997). 1West Virginia Department of Environmental Protection, HC 63 Box 2545, Romney, WV 26757. 2Biology Department, Bates College, 44 Campus Avenue, Lewiston, ME 04240. *Corresponding author - 506 Northeastern Naturalist Vol. 17, No. 3 Exposure and vulnerability of cottontails to predation is greater during winter due to the scarcity of high-quality food (Villafuerte et al. 1997). The winter diet of Appalachian Cottontails is not well known. Spencer (1985) compared stomach contents of Sylvilagus floridanus J.A. Allen (Eastern Cottontails) and Appalachian Cottontails in western Maryland and West Virginia. Most (85%) of the winter (January–March) diet of Appalachian Cottontails in western Maryland and West Virginia was woody material. Despite their predominance in the understory, Kalmia latifolia (Mountain Laurel) and Rhododendron maximum L. (Great Rhododendron) were absent from stomachs of rabbits in Maryland, and Mountain Laurel and Vaccinium spp. (blueberry) from Appalachian Cottontails in West Virginia. Spencer (1985) suggested that plants more palatable to rabbits occurred in these areas, including Betula lutea Michx. f. (Yellow Birch) and Crataegus spp. (hawthorn). Mountain Laurel and rhododendrons produce an andromedotoxin that could render them unpalatable to rabbits. Picea rubens Sarg. (Red Spruce) was ingested by some Appalachian Cottontails. A relationship was implied between the use of Tsuga canadensis (L.) Carr (Eastern Hemlock) in the diet and snow cover or inclement weather (Spencer 1985). The purposes of our study were to examine survival rates of Appalachian Cottontails and compare these between adults and subadults, and between males and females, during leaf-off (October–April) and leaf-on (May–September) seasons. We also investigated selection of woody plant species in the winter diet. Male Appalachian Cottontails at Dolly Sods traveled farther between successive resting locations than females did in the leaf-on season (Boyce 2001), so we suspected that males would have lower survival rates than females. We also expected that monthly survival during leaf-off seasons would be lower than during leaf-on seasons. We examined winter forage use to determine whether, consistent with previous studies, Appalachian Cottontails would select Rubus spp. and the bark, buds, and small branches of Acer spp. (maple) and Betula spp. (birch) trees. In addition, we investigated whether they would browse Red Spruce and Eastern Hemlock and avoid Great Rhododendron and Mountain Laurel. Because stochastic extinction events can occur in small populations, knowledge of such critical factors as survival and winter diet of Appalachian Cottontails is important. Survival rates are essential elements of population trend analyses. Wildlife managers can consider preferred woody plants when developing habitat plans for Appalachian Cottontails. Methods Study area Dolly Sods is a high-elevation (790–1260 m) area in the Monongahela National Forest of northeastern West Virginia (Tucker and Grant counties, 39°01'N, 79°19'W) consisting of a 4134-ha wilderness area and a 971-ha scenic area (Venable 1996). Its climax forest of Red Spruce was logged and burned in the late 1800s, and the area has since become characterized by scrubby plains and bogs interspersed with stands of spruce and Eastern 2010 A.C. Hartman and R.E. Barry 507 Hemlock and boulder fields (Chapman and Morgan 1973; Chapman et al. 1977; A.C. Hartman, pers. observ.). Shrubs include Great Rhododendron, Mountain Laurel, and blueberry. Most of our work was done in the vicinity of Forest Road 75, which runs north to south through the area, and the Red Creek Campground. The climate is generally cool, windy, and wet, with >130 cm of precipitation per year. The area is subject to frosts year-round and frequent ice storms in winter, and annual snowfall can reach 380 cm (Venable 1996). Dolly Sods supports 2 other lagomorph species, Lepus americanus Erxleben (Snowshoe Hare) and Eastern Cottontail. Procedures The study was conducted from October 1997 through April 2000. Fortyfour Appalachian Cottontails were captured in wooden livetraps (18 by 22 by 60 cm) baited with apple slices or alfalfa pellets. Rabbits in traps were transported to Frostburg State University, Frostburg, MD, where they were weighed, anesthetized (30–45 mg ketamine HCl/kg body mass), measured (total length, hind foot, and ear), and gender recorded. Initial species identification was based on external characteristics and a discriminant function originally developed to differentiate New England Cottontails and Eastern Cottontails (Litvaitis et al. 1991). Species identification was later confirmed by electrophoretic analysis of blood serum proteins (Morgan and Chapman 1979, Sommer 1997). Rabbits were ear-tagged and radiocollared. One collar type was designed for rabbits and hares (Lotek Engineering, Inc., Newmarket, ON, Canada), and we modified the other style (Advanced Telemetry Systems, Isanti, MN), designed for Bonasa umbellus L. (Ruffed Grouse), to fit rabbits. Both styles had an expected battery life of 14–18 months, and both had mortality/motion sensors. Monitoring and survival estimates. Rabbits were released at capture sites, usually within 24 h. We tracked rabbits directly to their daytime resting locations on average 2 times per week (with considerable variation) and at various times during daylight hours. In most cases, rabbits were visible in, or fleeing from, the resting location; if not, the presence of pellets, browse, a small, oval depression, or melted snow marked the spot from which they had fled. Each radiolocation was field-marked. We compiled the dates on which each rabbit entered the study (i.e., capture date) and those on which each rabbit became no longer part of the study. For rabbits that died (n = 33), we used the date when the mortality signal was first heard as the end date. For rabbits whose radio signals were lost (n = 8), we used the last date on which they were seen alive or their signal was heard as the end date. These 8 animals were considered “censored” on this end date in all survival estimates. We saw no justification to use any “adjustment period” (Pollock et al. 1989) to exclude the few rabbits that died shortly after release. Two survivorship curves were generated, 1 based on trap mortalities being considered as censoring events, and the other based on trap mortalities being considered as death events. We statistically compared the 2 curves using the log-rank test (Pollock et al. 1989), and the null hypothesis that the curves are equal could not be rejected (P > 0.05 for the most conservative χ2 test; Cox and Oakes 1984). Therefore, we treated trap mortalities as death events for all survival 508 Northeastern Naturalist Vol. 17, No. 3 estimates. We compared rabbit survival by weight (i.e., age class), season, and sex. Individuals ≤700 g were considered subadults, and those >700 g were identified as adults. To determine whether to include the 4 subadults in survival estimates, we performed the log-rank test on the survival curves based on all individuals and only adults. The null hypothesis of equality/ similarity could not be rejected (P > 0.05), so the 2 data sets appear to be equally representative samples of the population. However, we chose not to include subadults in the survival estimates that were partitioned by sex and season. The sample size of subadults was too small to reveal a statistical difference between the survival of subadult and adult cottontails. In order to obtain Kaplan-Meier survival estimates (Pollock et al. 1989) and their associated 95% confidence intervals (Cox and Oakes 1984) over the entire period of interest, we used the dates each rabbit entered the study and the end dates for each rabbit. The Kaplan-Meier method, or product limit estimator, has several advantages over the binomial or Mayfield methods. First, it does not assume a constant hazard function underlying the data. Second, it allows for the gradual, or staggered, entry of individuals after the study has begun. Finally, it allows right-censored individuals (i.e., those whose survival time is only known to be greater than some value, perhaps because of a failed transmitter) to be included in the analysis until the date of disappearance (Pollock et al. 1989). The study encompassed 918 days, 25 October 1997 to 30 April 2000 (Sucke 2002). Three leaf-off and 2 leaf-on seasons were identified. Twentyone individuals generated data for >1 season. The period of interest for each leaf-on season (1998: n = 15, 1999: n = 13) was 153 days. Periods of interest for leaf-off seasons were 187 days for 1997–1998 (n = 13 rabbits), 212 days for 1998–1999 (n = 19), and 213 days for 1999–2000 (n = 9). In the comparison of survival estimates of adults and subadults, the period of interest for adults was 918 days (the duration of the study, n = 40) and for subadults was 58 days (26 August–23 October 1998, n = 4). We divided the data into 2 separate time periods to analyze male versus female survival because the number “at risk” for males reached 0 after 11 January 1998, which rendered further values of S(t), the survivorship function at time t, impossible to obtain. One female rabbit was used in both periods. Although data were available for females for longer periods than those reported, we truncated the female study periods to match data available for males. Period 1 was 70 days (31 October 1997–9 January 1998, n = 4 males, 4 females) and Period 2 was 691 days (11 April 1998–2 March 2000, n = 18 males, 14 females). The estimate of survival rate for the entire period analyzed was used to estimate the finite survival rate, Ŝ(t), for 1 day, 1 month (28 days) , and 1 year (365 days). Finite yearly survival rate was not calculated for any data set that had an entire period of <365 days, e.g., all leaf-on/leaf-off data sets, and Period 1 male/female data sets. The estimated finite survival rate for 1 day (“daily” survival rate) is calculated by [S(t)]1/t, where S(t) is the survival rate at the end of a study period t days long (Krebs 1999; D.R. Diefenbach, in litt.). Estimated survival rates for any number of days >1 day are calculated by [Ŝ(1)]t, where Ŝ(1) is the daily survival rate, and t is the number of days in the period of interest, e.g., 28 or 365. Ninety-five percent confidence 2010 A.C. Hartman and R.E. Barry 509 intervals for these figures were obtained from the original variance and the delta method (Powell 2007, Seber 2002; D.R. Diefenbach, in litt.). Survival estimates were compared by gender, age class, and season by examining confidence intervals for overlap. The criterion for statistical significance for all analyses was α = 0.05. Winter diet. Browsed stems were identified and counted within a 1-m radius of winter (1 November–31 March) radiolocations for each of 15 individuals, 12 in 1998–99 and 5 in 1999–2000. Two individuals generated data for both years, but observations in different years were considered independent because of the time between them. Browsed stems were defined as woody stems with evidence of having been bitten off cleanly by rabbits (Todd 1927) as opposed to having been torn off by Odocoileus virginianus Zimmerman (White-tailed Deer). We assumed the stems were not browsed by other lagomorphs because Snowshoe Hares and Eastern Cottontails were uncommon. Stems such as Vaccinium spp. or Gaultheria procumbens (Eastern Teaberry) that had >1 browsed portion were counted as a single stem. During winter 1999–2000, some browse data were collected immediately after locating the rabbit. For all locations in winter 1998–99 and the remaining in winter 1999–2000, browse locations were immediately field-flagged, and data were collected by returning to the location at a later date when more time could be spent in the field. Unidentified browsed or available vegetation never accounted for >2.9% of browsed stems or >0.6% of available stems for any individual. Plant species browsed at ≥1 locations were assigned to 13 diet components (Table 1). We analyzed browse data with the rank-preference index (Johnson 1980, Krebs 1999) using the program PREFER 5.1 (Pankratz 1994). Analysis with this index usually is not affected by rare items in the diet (Krebs 1999). For each rabbit analyzed, this method subtracted the rank of each diet component with respect to availability from its rank with respect to use to find the difference in ranks (ti) for each diet component. Program PREFER yielded average (for all rabbits) differences in ranks (T) for each of the 13 diet components. Availability was derived for all species browsed by any rabbit in either winter. To determine availability for winter 1998–99, the number of stems of each available species that occurred within a 1-m radius of winter radiolocations was tallied from the microhabitat study of Boyce (2001). For winter 1999– 2000, we counted available and browsed stems on the same occasion. Because Spencer (1985) reported conifer needles in the stomachs of Appalachian Cottontails, we noted whether Red Spruce needles were available within the 1-m radius plot at 93 of the 167 food locations studied. The sample included locations of 10 rabbits in winter 1998–1999 and 5 in winter 1999–2000. Results We captured and radio-collared 44 Appalachian Cottontails (24 males, 20 females) and 1 male Eastern Cottontail (not included in subsequent analyses) from 25 October 1997 to 11 January 2000 over 6751 trap nights. Rabbits were captured with less effort (12–108 trap nights/individual) during the months of September through December (except November 1998, with 238 510 Northeastern Naturalist Vol. 17, No. 3 trap nights/individual) than at other times of the year. Mean weight of 18 adult females was 1100 g (range = 850–1350 g). Mean weight of 21 adult males was 1000 g (range = 750–1300 g); weight for 1 male was not obtained. Four individuals were subadults. Survival The median number of days individuals (n = 44) were in the study was 63 (range = 2 to 869). For adults (n = 40), the median was 80 (range = 2 to 869) days. Mean finite survival rate for all Appalachian Cottontails over the entire 918-day study was 0.0023 (95% confidence interval = 0–0.0054). This corresponds to a finite daily survival rate of 0.9934 (0.9922–0.9946), finite monthly (28-day) survival rate of 0.8309 (0.8023–0.8596), and finite yearly survival rate of 0.0894 (0.0493–0.1296). The mean finite daily survival rate was similar for subadults (0.9764) and adults (0.9936). Estimates for the 2 groups were different at the monthly level (0.5121 for subadults and 0.8349 for adults), but variability was much greater for subadults and confidence intervals overlapped. Survival rate dropped sharply after 60 days (t = 60) and was <0.1 after 3.5 months (Fig. 1). During Period 1, daily survival rate for males was 0.9747 (0.9498– 0.9996) and for females was 0.9901 (0.9763–1.0040). During Period 2, daily survival rate for males was 0.9948 (0.9920–0.9976) and for females was 0.9964 (0.9951–0.9978). Confidence intervals of male and female survival rates also overlapped at the monthly level in both periods, and at the yearly level in Period 2. Daily survival rate during leaf-off 1997–1998 was 0.9852 (0.9801– 0.9902), significantly lower than for all other seasons (means ≥0.9947). The 28-day survival rate was 0.6578 (0.5642–0.7513), also significantly lower than for other seasons (means ≥0.8628). Confidence intervals overlapped between all remaining seasons for both daily and 28-day levels. Predation was the most frequently confirmed cause (n = 15) of mortality among 41 Appalachian Cottontails that died during the study. Winter diet Food items browsed by Appalachian Cottontails at winter radiolocations were placed into 13 categories (Table 1). All diet components were not preferred equally (F12,5 = 6.10, P < 0.05). Amelanchier spp. (serviceberry), Lonicera sp. (honeysuckle), and Photinia spp. (chokeberry) were among the most-preferred items (T < -1.0; Table 1), although honeysuckle was present in very low numbers (only 2 stems of honeysuckle were browsed of 2 available; Appendix I). Rubus spp. were used in proportion to availability. The mostavoided components (T > 1.0 ) were Mountain Laurel, Rhododendron spp., and the “other” group. Taxa ranked “preferred” and also representing >20 browsed stems included only chokeberry, Eastern Teaberry, and blueberry/ huckleberry. When we truncated the number of diet items to the only 3 that comprised >5% of available stems and re-analyzed with the rank-preference index, Eastern Teaberry and blueberry/huckleberry were preferred, and Mountain Laurel was avoided. For 7 rabbits, >50% of locations contained Red Spruce needles. Four rabbits had >50% of locations without spruce needles. 2010 A.C. Hartman and R.E. Barry 511 Figure 1. Kaplan-Meier survival curve for S. obscurus for all individuals (n = 44). S(t) = proportion surviving past time t (number of days). Error bars indicate 95% confidence intervals. Tracking began at day 6. 512 Northeastern Naturalist Vol. 17, No. 3 Fifty percent of locations of 1 rabbit housed spruce needles. Of the remaining 3 rabbits, 2 had spruce needles in the only location examined, and 1 had no spruce needles in either of the 2 locations examined. Discussion Data were insufficient to address the speculation that subadults have lower survival rates than adults. The expectation that female survival rates would be higher than those of males was not supported by the data, although notable, albeit nonsignificant, differences in means (greater for females) suggest that biological differences between the sexes might be found with a more powerful experimental design. The assertion that males travel farther during the leaf-on than leaf-off season (Boyce 2001), thereby increasing their risk of predation, actually indicates that data should be separated on the basis of season and sex for analysis in a study with larger sample sizes. Sample size in the current study was too small to partition in this way. Our speculation that survival rates would be lower in leaf-off than leaf-on seasons was supported only by the first of the 3 leaf-off seasons. The delineation of seasons that was used was based on previous studies of Appalachian Cottontails in western Maryland (Sommer 1997) and at Dolly Sods (Boyce 2001), which were focused primarily on patterns of habitat use. Perhaps future survival studies should define leaf-off, or winter, as a short period during which weather is harsh (Keith and Bloomer 1993), or delineate seasons on the basis of breeding onset (Bond et al. 2001), in an effort to reveal other patterns. That survival rates in leaf-on seasons were not higher might be attributable to home ranges being larger during the leaf-on than leaf-off season at Table 1. Winter diet components of Sylvilagus obscurus (Appalachian Cottontail) and associated T values generated by Johnson’s (1980) rank-preference index. Largest average differences in browsed and available ranks (T) denote the most preferred (negative) or avoided (positive) diet components. See Appendix I for names of species and common names of taxa contained within each multiple-species diet component. T values Winter diet component All available taxa 3 most available taxa Amelanchier spp. -1.647 Lonicera sp. -1.588 Photinia spp. -1.235 Acer rubrum L. (Red Maple) -0.822 Hamamelis virginiana L. (American Witchhazel) -0.412 Gaultheria procumbens L. (Eastern Teaberry) -0.294 -0.412 Vaccinium spp. and Gaylussacia baccata (Wangenh.) -0.059 -0.059 K. Koch (Black Huckleberry) Rubus spp. 0.000 Viburnum spp. 0.029 Ilex montana Torr. & Gray ex Gray (Mountain Holly) 0.941 and Nemopanthus mucronatus (L.) Loes (Mountain Holly) Rhododendron spp. 1.059 Kalmia latifolia L. (Mountain Laurel) 1.941 0.471 Other (7 species) 2.147 2010 A.C. Hartman and R.E. Barry 513 Dolly Sods (Boyce and Barry 2007). Although leaves increase concealment cover, rabbits with large home ranges cover greater distances, potentially encountering marginal habitat and higher risk of predation. Converting daily, 60-day, and 70-day estimates reported by others to monthly estimates allowed us to compare our results, obtained at the type locality of Appalachian Cottontails where rabbits were widely distributed and active over a large area (Sucke 2002), with those from other cottontail populations. The overall monthly estimate (0.8309) for Dolly Sods Appalachian Cottontails was within the ranges reported for 2 populations of Eastern Cottontails (Bond et al. 2001, Keith and Bloomer 1993) and was only slightly lower than survival estimates reported for another population of Eastern Cottontails (Trent and Rongstad 1974) and a population of New England Cottontails in large (source) patches (Barbour and Litvaitis 1993). It was higher than the survival of New England Cottontails in smaller (sink) patches. Daily survival rates were comparable to those obtained for Eastern Cottontails at Cape Cod, MA by Boland and Litvaitis (2008). Serviceberry and chokeberry, preferred food items in the diet of Appalachian Cottontails, are known foods for cottontails (Van Dersal 1938). Red Spruce was browsed only at 1 location, and presence/absence of spruce needles at daytime resting sites (food locations) did not reveal a pattern. Even if needles were abundant at locations, they may have indicated the importance of spruce for cover rather than food. Hemlock was not browsed, rabbits avoided Mountain Laurel, and data were insufficient to analyze Great Rhododendron separately. Vaccinium spp. was abundant at resting locations and was browsed frequently in combination with Gaylussacia baccata (Black Huckleberry). However, this group was used nearly in proportion to its availability, suggesting that these browse items collectively might constitute a staple component of the Appalachian Cottontail diet. The expectation that Rubus spp. would be a preferred item of the winter diet of Appalachian Cottontails also was not supported. Buds and small shoots of maples were scarce, and only 1 individual browsed on plants in this taxon (A. rubrum, specifically). Future investigators should consider radiolocating rabbits during dusk and dawn hours when they are thought to be most active and feeding (Dalke and Sime 1941). Management implications This study provides wildlife managers with initial survival estimates for a population of Appalachian Cottontails at the type locality in habitat that provides plentiful concealment and thermal ericaceous cover (Boyce 2001). In addition, it identifies Eastern Teaberry, blueberries, and Black Huckleberry, and possibly chokeberry, as woody species important to this rabbit for winter browse. Succession is retarded at Dolly Sods because of poor soils and a harsh climate (Sucke 2002), so ample habitat that provides suitable cover and food resources for Appalachian Cottontails is likely to persist there. Nevertheless, management to preserve critical habitat at the site by such means as controlled burns has been suggested (Venable 1996), and management that accommodates factors that contribute to survival, such 514 Northeastern Naturalist Vol. 17, No. 3 as ground cover and preferred winter foods, may be critical to the persistence of Appalachian Cottontails in smaller, isolated patches. Acknowledgments We thank the West Virginia Division of Natural Resources and Frostburg State University for the funding of this project and the USDA Forest Service for access to the study site, use of a cabin, and use of GIS files. Mitch Spear donated his snowmobile for the duration of the study. Drs. J. Edward Gates and Ray Morgan of the Center for Estuarine and Environmental Studies Appalachian Laboratory (University of Maryland) loaned us GPS and electrophoretic equipment and provided the use of their labs. Drs. Gwen Brewer, L. Michelle Bowe, Durland Shumway, Lance Revennaugh, and Chrismarie Baxter (deceased), all of Frostburg State University, also provided support and expertise. Kelly Boyce contributed significant help in the field and with the literature search, home-range, and microhabitat data. The following also contributed to field work: Nancy Bensley, Randy Mowrer, Bob Cordes, Frank Butera, Kieran O’Malley, Jeff Peters, Bianca McIntyre, Paul Wenninger, Sandy Davis, Julie York, Sean Kline, Angela Donroe, Steve Doll, Terry McCullough, Mark Lewis, and Jan Ferrigan. Literature Cited Barbour, M.S., and J.A. Litvaitis. 1993. Niche dimensions of New England Cottontails in relation to habitat patch size. Oecologia 95:321–327. Barry, R.E., N. Bensley, and K.A. Boyce. 1997. Range, density, habitat breadth, and daily survival of the Appalachian Cottontail (Sylvilagus obscurus) in western Maryland. Final Report to the Maryland Heritage and Biodiversity Conservation Programs, Annapolis, MD. Boland, K.M., and J.A. Litvaitis. 2008. Role of predation and hunting on Eastern Cottontail mortality at Cape Cod National Seashore, Massachusetts. Canadian Journal of Zoology 86:918–927. Bond, B.T., L. W. Burger, B.D. Leopold, and K.D. Godwin. 2001. Survival of Cottontail Rabbits (Sylvilagus floridanus) in Mississippi and an examination of latitudinal variation. American Midland Naturalist 145:127–136. Boyce, K.A. 2001. Distribution, seasonal home range, movements, and habitat of the Appalachian Cottontail, Sylvilagus obscurus, at Dolly Sods, West Virginia. M.Sc. Thesis. Frostburg State University, Frostburg, MD. Boyce, K.A., and R.E. Barry. 2007. Seasonal home range and diurnal movements of Sylvilagus obscurus (Appalachian Cottontail) at Dolly Sods, West Virginia. Northeastern Naturalist 14:99–110. Chapman, J.A., and R.P. Morgan. 1973. Systematic status of the cottontail complex in western Maryland and nearby West Virginia. Wildlife Monographs 36:1–54. Chapman, J.A., and J.R. Stauffer. 1981. The status and distribution of the New England Cottontail. Pp. 973–983, In K. Meyers and C.D. McInnes (Eds.). Proceedings of the World Lagomorph Conference. University of Guelph, Guelph, ON, Canada. Chapman, J.A., A.L. Harman, and D.E. Samuel. 1977. Reproductive and physiological cycles in the cottontail complex in western Maryland and nearby West Virginia. Wildlife Monographs 56:1–73. Chapman, J.A., J.G. Hockman, and W.R. Edwards. 1982. Cottontails. Pp. 83–123, In J.A. Chapman and G.A. Feldhamer (Eds.). Wild Mammals of North America. Johns Hopkins University Press, Baltimore, MD. Chapman, J.A., K.L. Cramer, N.J. Dippenaar, and T.J. Robinson. 1992. Systematics and biogeography of the New England Cottontail Sylvilagus transitionalis (Bangs, 1895), with the description of a new species from the Appalachian Mountains. Proceedings of the Biological Society of Washington 105:841–866. 2010 A.C. Hartman and R.E. Barry 515 Cox, D.R., and D. Oakes. 1984. Analysis of Survival Data. 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Physiological responses by lagomorphs to resource limitations imposed by habitat fragmentation: Implications to condition-sensitive predation. Canadian Journal of Zoology 75:148–151. West Virginia Natural Heritage Program. 2007. Rare, threatened, and endangered species in West Virginia. West Virginia Division of Natural Resources, Elkins, WV. Available online at Accessed 14 October 2008. 516 Northeastern Naturalist Vol. 17, No. 3 Appendix I. Number of stems of each food component browsed by (and available to) S. obscurus at Dolly Sods (F = female, M = male). * = individuals from winter 1999–2000; other individuals from winter 1998–1999. Amel. = Amelanchier; I. m./N m. = Ilex montana and Nemopanthus mucronatus; Rhod. = Rhododendron. The group Vaccinium spp. (blueberry and huckleberry) included V. angustifolium Ait., V. myrtilloides Michx., V. pallidum Ait., and Gaylussacia baccata (Wangenh.) K. Koch. Rubus spp. (blackberry and raspberry) was represented mainly by R. hispidus L. (Bristly Dewberry), which usually occurred at Dolly Sods as small (< 3-mm dia.), somewhat woody shoots close to the ground. Other species in this category in small numbers were R. allegheniensis Porter and R. occidentalis L. Photinia spp. (chokeberry) included mostly P. pyrifolia (Lam.) Robertson & Phipps, but also some P. melanocarpa (Michx.) Robertson & Phipps. Amelanchier spp. (serviceberry) included A. arborea (Michx. f.) Fern. and A. laevis Weig. Ilex montana Torr. & Gray ex Gray and Nemopanthus mucronatus (L.) Loes (both Mountain Holly) comprised a category. Most of the Viburnum spp. counted were V. nudum L.var. cassinoides (L.) Torr. & Gray, although some may have been V. lentago L. Rhododendron spp. (azaleas) included R. viscosum (L.) Torr. and R. prinophyllum (Small) Millais. The “other” diet component consisted of 7 plant species—Quercus ilicifolia Wangenh. (Bear Oak), Quercus alba L. (White Oak), R. maximum, Pinus resinosa Soland.(Red Pine), Picea rubens Sarg. (Red Spruce), Alnus incana ssp. rugosa (Du Roi) Clausen (Speckled Alder), and Hydrangea arborescens L. (Wild Hydrangea)— that each were browsed at only 1 location. Browse item Vaccinium Gaultheria Rubus Photinia Kalmia Amel. I. m./ Hamamelis Viburnum Rhod. Acer Lonicera Other Rabbit ID spp. procumbens spp. spp. latifolia spp. N. m. virginiana spp. spp. rubrum sp. (7 species) F4 161(622) 11(90) 35(95) 1(38) 7(230) 6(6) 0(19) 0(0) 2(2) 1(18) 2(2) 0(0) 2(8) F10 139(989) 21(250) 5(28) 9(44) 1(218) 2(2) 1(16) 0(0) 0(7) 0(0) 0(0) 1(1) 0(26) F12 137(1041) 14(70) 0(0) 0(0) 14(217) 0(0) 0(13) 0(1) 1(12) 0(0) 0(0) 0(0) 2(177) F15 169(1404) 21(491) 3(128) 20(27) 3(111) 0(0) 0(0) 0(1) 0(0) 0(0) 0(0) 0(0) 0(8) F14 61(421) 1(41) 0(0) 5(17) 0(98) 0(0) 0(0) 0(0) 0(0) 0(10) 0(0) 0(0) 0(10) M7 65(1158) 8(22) 6(6) 10(17) 8(140) 0(0) 0(6) 2(2) 0(8) 0(16) 0(1) 1(1) 0(9) M10 197(613) 14(49) 0(12) 1(16) 4(158) 0(0) 0(40) 0(0) 0(0) 0(11) 0(0) 0(0) 0(2) M13 180(711) 12(70) 5(53) 5(10) 15(168) 0(0) 4(14) 0(0) 0(6) 1(31) 0(0) 0(0) 2(11) M15 129(671) 4(33) 16(47) 5(31) 3(282) 0(0) 1(38) 0(0) 3(3) 0(0) 0(1) 0(0) 12(128) M16 95(425) 11(55) 0(57) 2(4) 3(206) 0(0) 0(0) 0(2) 0(0) 0(0) 0(0) 0(0) 0(17) M17 151(878) 14(94) 2(2) 25(36) 12(238) 1(1) 0(1) 0(2) 0(2) 0(13) 0(1) 0(0) 0(4) M18 16(914) 1(215) 0(1) 7(15) 0(32) 0(0) 0(0) 0(0) 0(0) 0(0) 0(0) 0(0) 0(5) F4* 182(1019) 16(275) 27(80) 17(39) 14(242) 0(0) 3(9) 0(0) 0(13) 0(29) 0(3) 0(0) 0(6) F17* 294(1648) 16(274) 2(10) 8(50) 11(233) 0(0) 0(0) 2(15) 0(0) 0(0) 1(3) 0(0) 0(14) F20* 29(81) 1(3) 0(5) 0(0) 12(107) 2(7) 0(5) 3(6) 0(0) 0(3) 0(0) 0(0) 3(4) M15* 167(1395) 7(216) 3(27) 4(33) 5(101) 0(0) 0(1) 0(0) 1(5) 0(0) 0(2) 0(0) 0(10) M24* 89(403) 17(109) 17(56) 1(4) 7(90) 0(0) 0(0) 0(0) 0(4) 2(15) 0(0) 0(0) 0(2) Totals 2261(14,393) 334(2357) 121(707) 120(381) 119(2871) 11(16) 9(162) 7(29) 7(62) 4(146) 3(13) 2(2) 21(441).