Estimating Deer Populations Using Camera Traps and Natural Marks

Despite the ubiquity of camera traps in wildlife monitoring projects, the data gathered are rarely used to estimate wildlife population demographics, a critical step in detecting declines, managing populations, and understanding ecosystem health. In contrast to abundant white-tailed deer (Odocoileus virginianus) in the eastern United States, black-tailed deer (Odocoileus hemionus columbianus) in the western United States have declined over the past several decades. We tested whether passively operating camera traps can be used to quantify population characteristics for black-tailed deer. We used images of naturally occurring physical characteristics of deer to develop movement and activity data and inform a Bayesian spatial mark-resight model that estimates deer abundance, density, sex ratio, ratio of fawns to adult females, and home range size. We developed the model to account for the effect of attractants (bait) on encounter rate. We placed 13 cameras on all known water sources of a private ranch in California and provided bait once a month in front of each camera. Over 9,000 visits occurred between 24 May 2012 and 21 January 2013, and we identified 50 individual deer from ear notches or antler characteristics. We estimated density at 7.7 deer/km² in summer and 8.6 deer/km² in fall. In the summer, home ranges were 2.3 km² for females and fawns and 16.8 km² for males. Home ranges constricted slightly in fall. We estimated a sex ratio of 12.5 males/100 females, and a ratio of 47.0 fawns/100 adult females. Bait increased baseline encounter rates (visits/week) by 3.7 times in summer and 4.95 times in fall. We found slightly higher densities of deer in our study area compared to other recent studies in more mountainous areas of California, and lower male:female sex ratios. This approach shows that commonly deployed camera traps can be used to quantify population characteristics, monitor populations, and inform harvest or habitat management decisions. © 2019 The Wildlife Society.     

Climatically driven changes in primary production propagate through trophic levels

Climate and land‐use change are the major drivers of global biodiversity loss. Their effects are particularly acute for wide‐ranging consumers, but little is known about how these factors interact to affect the abundance of large carnivores and their herbivore prey. We analyzed population densities of a primary and secondary consumer (mule deer, Odocoileus hemionus, and mountain lion, Puma concolor) across a climatic gradient in western North America by combining satellite‐based maps of plant productivity with estimates of animal abundance and foraging area derived from Global Positioning Systems telemetry data (GPS). Mule deer density exhibited a positive, linear relationship with plant productivity (r² = 0.58), varying by a factor of 18 across the climate‐vegetation gradient (range: 38–697 individuals/100 km²). Mountain lion home range size decreased in response to increasing primary productivity and consequent changes in the abundance of their herbivore prey (range: 20–450 km²). This pattern resulted in a strong, positive association between plant productivity and mountain lion density (r² = 0.67). Despite varying densities, the ratio of prey to predator remained constant across the climatic gradient (mean ± SE = 363 ± 29 mule deer/mountain lion), suggesting that the determinacy of the effect of primary productivity on consumer density was conserved across trophic levels. As droughts and longer term climate changes reduce the suitability of marginal habitats, consumer home ranges will expand in order for individuals to meet basic nutritional requirements. These changes portend decreases in the abundance of large‐bodied, wide‐ranging wildlife through climatically driven reductions in carrying capacity, as well as increased human–wildlife interactions stemming from anthropogenic land use and habitat fragmentation.     

Estimating abundance of Sitka black-tailed deer using DNA from fecal pellets

Densely vegetated environments have hindered collection of basic population parameters on forest-dwelling ungulates. Our objective was to develop a mark–recapture technique that used DNA from fecal pellets to overcome constraints associated with estimating abundance of ungulates in landscapes where direct observation is difficult. We tested our technique on Sitka black-tailed deer (Odocoileus hemionus sitkensis) in the temperate coastal rainforest of Southeast Alaska. During 2006–2008, we sampled fecal pellets of deer along trail transects in 3 intensively logged watersheds on Prince of Wales Island, Alaska. We extracted DNA from the surface of fecal pellets and used microsatellite markers to identify individual deer. With genotypes of individual deer, we estimated abundance of deer with moderate precision (±20%) using mark–recapture models. Combining all study sites, we identified a 30% (SE = 5.1%) decline in abundance during our 3-year study, which we attributed to 3 consecutive severe winters. We determined that deer densities in managed land logged >30 years ago (7 deer/km², SE = 1.3) supported fewer deer compared to both managed land logged <30 years ago (10 deer/km², SE = 1.5) and unmanaged land (12 deer/km², SE = 1.4). Our study provides the first estimates of abundance (based on individually identified deer) for Sitka black-tailed deer and the first estimates of abundance of an unenclosed ungulate population using DNA from fecal pellets. Our tool enables managers to accurately and precisely estimate the abundance of deer in densely vegetated habitats using a non-invasive approach. © 2011 The Wildlife Society.     

Effects of Earn-a-Buck and Special Antlerless-Only Seasons on Wisconsin's Deer Harvests

ABSTRACT Effective management of wildlife populations often requires motivating hunters to harvest sufficient numbers of animals of prescribed sex and age classes to meet management goals. For cervids, it is convenient to design harvest regulations relative to presence (male) or absence (young and female) of antlers because harvest of females has a larger effect on population growth. We used regression techniques to evaluate effects of 2 supplemental hunting programs based on additional days of hunting opportunity and an additional incentive used to complement additional days on harvest of antlered and antlerless deer in Wisconsin, USA. Earn-a-buck regulations, an incentive-based program that requires hunters to register an antlerless deer before being authorized to harvest an antlered deer, were associated with an average increase of 2.04 deer/km² in antlerless harvest and a 0.60 deer/km² decrease in harvest of antlered deer. Providing more opportunity for hunting of antlerless deer in the form of 4- and 8-day supplemental firearm seasons was associated with 1.10 deer/km² and 1.32 deer/km² increases, respectively, in antlerless harvest with trivial (0.02 deer/km² and 0.09 deer/km²) decreases in harvests of antlered deer. Our analysis suggests that extra days of hunting opportunity coupled with the earn-a-buck incentive was 56–88% more effective at increasing antlerless harvest relative to additional days of hunting without the incentive. Use of the earn-a-buck incentive resulted in decreased harvest of antlered deer and was disliked by many hunters. Quantifying these relationships is important for helping managers predict the costs and benefits of various hunting programs.     

Censusing rainforest game species with communal net hunts

This paper presents a method to address two wildlife management problems in central African rainforests: the need for local communities to take responsibility for wildlife management, and the lack of simple and appropriate wildlife monitoring techniques. The method uses encounters of game species during net hunts to calculate abundance indices as well as to estimate population densities for the four principal game species in the Dzanga–Sangha region: the duikers Cephalophus monticola (10.7–20.4 km^?2), C. dorsalis (1.2–2.0 km^?2), and C. callipygus (0.9–1.2 km^?2), and the brush-tailed porcupine Atherurus africanus (2.7–5.3 km^?2). Game species behaviour, the hunting practice, and comparisons with results from other research across central Africa suggest that the method can provide valid density estimates for C. monticola and C. dorsalis, but only abundance indices for C. callipygus and A. africanus. Nevertheless, the method can be applied by hunters in the course of their normal activities, and is adapted to the local habitat types and game species. As such, it can be an important tool for local communities in developing sustainable wildlife management programmes.     

Can Public Meetings Accurately Reflect Public Attitudes Toward Wildlife Management?

Abstract: State wildlife agencies often use input obtained through public meetings to develop management policies. Because public meetings can be dominated by single stakeholder groups, these policies may not reflect the attitudes of new wildlife stakeholders. In 2000 the Utah Wildlife Board, after a series of public meetings, adopted a statewide policy for winter-feeding mule deer (Odocoileus hemionus). The policy was implemented by the Utah Division of Wildlife Resources from 2001 to 2007 in Cache County of northern Utah, USA. In 2007, we surveyed Utah households representing metropolitan, nonmetropolitan, and Cache County residents (n = 1,800) to evaluate whether the winter-feeding policy reflected the attitudes of all wildlife stakeholders. Survey respondents, regardless of residence strata, believed winterfeeding programs were essential for managing mule deer in Utah (χ²₆ = 7.02, P = 0.32). However, most respondents were reluctant to support feeding programs at the expense of habitat restoration projects (χ²₆ = 11.64, P = 0.07). Our results suggest that the winter-feeding policy represented the attitudes of the Utah residents surveyed, though few had participated in its development. Respondents' strong utilitarian attitudes toward wildlife (e.g., strong support for hunting and feeding) influenced those respondents' perceptions of the policy. Given the effects of increased urbanization on utilitarian attitudes toward wildlife in many parts of the United States, coupled with decreasing numbers of traditional wildlife stakeholders, state wildlife agencies should continually reevaluate their public involvement processes to ensure new wildlife stakeholders' attitudes and concerns are represented.     

Reduction and Maintenance of a White-Tailed Deer Herd in Central Massachusetts

Abstract: Controlled public hunts have been used in a variety of settings to reduce overabundant white-tailed deer (Odocoileus virginianus) herds. We present the results of a large-scale (160 km²) controlled hunt at Quabbin Reservation (QR) in central Massachusetts, USA. The QR was divided into 5 hunt zones. Hunting was initiated in each zone from 1991 to 1994 and continued through 2004. The management goal was to achieve posthunt deer densities of4 deer/km². Initial estimated deer densities in each zone ranged from 11.4 deer/km² to 27.6 deer/km². The management goals were reached in each zone after 2-4 years of hunting. Posthunt populations were maintained at or below the goal even though total hunter effort was reduced. Hunters were not required to harvest antlerless deer, but antlerless deer comprised 55-83% of the harvest each year. We simulated the effects of 5 years without hunting on deer populations. The simulated deer population exceeded management goals after 2 years. Our results demonstrate that controlled public deer hunts can effectively reduce deer populations and maintain them at desired levels over large areas with minimal hunter restrictions. Managers should prepare stakeholders during the hunt planning process for the need to continue overall harvest rates of >30% during the maintenance phase of a deer management program.     

Wildlife Interactions within Highway Underpasses

Highway underpasses are a common management tool used to lessen wildlife-vehicle collisions on roadways. Despite their widespread use, the effects of predator-prey interactions and human disturbances on wildlife within underpasses have not been well studied. To understand the effect of species interactions and human disturbances on wildlife traveling through underpasses, we analyzed camera data from 3 underpasses in Hallelujah Junction Wildlife Area, Sierra County, California, USA, from June 2017 to December 2018. We recorded 3,589 detections, which were predominately mule deer (Odocoileus hemionus), rodents, lagomorphs, California quail (Callipepla californica), bobcats (Lynx rufus), mountain lions (Puma concolor), and coyotes (Canis latrans). We used occupancy modeling and daily activity estimates to analyze species' spatial and temporal activity within the underpasses. Predator-prey interactions and human disturbances were among the most important factors that influenced wildlife travel through the underpasses. Mule deer avoided underpasses highly used by mountain lions, and mountain lions followed mule deer daily temporal activity patterns and seasonal activity patterns. These results indicate that predator-prey interactions influenced deer and mountain lion use of the underpasses. Coyotes favored underpasses and seasons with higher rodent and lagomorph presence, suggesting that the presence of prey was also important to coyote use of the underpasses. Coyotes, mountain lions, and bobcats all exhibited either temporal or spatial avoidance of human activity within the underpasses. California quail avoided predators within the underpasses and favored underpasses and times with high human activity. Our study suggests that underpass managers need to closely monitor the effect of predator-prey interactions and human activity on wildlife within underpasses to ensure these interactions do not discourage wildlife from using them. © 2019 The Wildlife Society.     

Habitat selection by mountain plovers in shortgrass steppe

Much of the breeding range for the mountain plover (Charadrius montanus) occurs in shortgrass steppe and mixed-grass prairie in the western Great Plains of North America. Studies of mountain plovers in shortgrass steppe during the 1970s and 1990s were focused in Weld County, Colorado, which was considered a key breeding area for the species. These studies, however, did not include habitats influenced by black-tailed prairie dogs (Cynomys ludovicianus) or prescribed fire. The role of these 2 rangeland disturbance processes has increased substantially over the past 15 years. During 2008–2009, I used radial distance point count surveys to estimate mountain plover densities early in the nesting season in 4 habitats on public lands in Weld County, Colorado. All 4 habitats were grazed by cattle during the growing season at moderate stocking rates but had different additional disturbances consisting of 1) dormant-season prescribed burns, 2) active black-tailed prairie dog colonies, 3) black-tailed prairie dog colonies affected by epizootic plague in the past 1–2 years, and 4) rangeland with no recent history of fire or prairie dogs. Mountain plover densities were similar on active black-tailed prairie dog colonies ( = 6.8 birds/km², 95% CI = 4.3–10.6) and prescribed burns ( = 5.6 birds/km², 95% CI = 3.5–9.1). In contrast, no plovers were detected at randomly selected rangeland sites grazed by cattle but lacking recent disturbance by prairie dogs or fire, even though survey effort was highest for this rangeland habitat. Mountain plover densities were intermediate (2.0 birds/km², 95% CI = 0.8–5.0) on sites where black-tailed prairie dogs had recently been extirpated by plague. These findings suggest that prescribed burns and active black-tailed prairie dog colonies may enhance breeding habitat for mountain plovers in shortgrass steppe and illustrate the potential for suppressed or altered disturbance processes to influence habitat availability for declining wildlife species. © 2011 The Wildlife Society.     

Parelaphostrongylus odocoilei: Life cycle in experimentally infected cervids including the mule deer, Odocoileus h. hemionus

The life cycle of a metastrongyloid nematode, Parelaphostrongylus odocoilei, was successfully completed in three members of the Cervidae: mule deer (Odocoileus h. hemionus), black-tailed deer (O. h. columbianus), and moose (Alces alces andersoni). The terrestrial gastropod, Triodopsis multilineata, was the experimental intermediate host. White-tailed deer (O. virginianus dacotensis) were refractory to infection. The prepatent period of P. odocoilei was significantly shorter in mule deer (X = 53 days) than in the black-tailed deer or moose. There was an inverse relationship between the size of the infective inoculum and the duration of the prepatent period of P. odocoilei in mule deer, but not in black-tailed deer. The duration and intensity of larval production of P. odocoilei were higher in mule deer than in the other hosts. Peak larval production in the feces (approximately 14,000 larvae/g) of mule deer was in excess of previous reports for elaphostrongyline nematodes, regardless of the size of the infective inoculum. Daily larval production, estimated at 3 to 4 × 10⁶ larvae/day, was six times higher than estimates for other elaphostrongylines. The duration of patency was not clearly established, but three mule deer and one black-tailed deer passed larvae for 12, 18, 24, and 18 months, respectively. On the basis of the reduced prepatent period and increased length and intensity of larval production, O. h. hemionus is considered the primary host of P. odocoilei.     

Invading white-tailed deer change wolf–caribou dynamics in northeastern Alberta

Human-caused habitat change has been implicated in current woodland caribou (Rangifer tarandus caribou) population declines across North America. Increased early seral habitat associated with industrial footprint can result in an increase in ungulate densities and subsequently those of their predator, wolves (Canis lupus). Higher wolf densities can result in increased encounters between wolves and caribou and consequently higher caribou mortality. We contrasted changes in moose (Alces alces) and deer (Odocoileus spp.) densities and assessed their effects on wolf–caribou dynamics in northeastern Alberta, Canada, pre (1994–1997) versus post (2005–2009) major industrial expansion in the region. Observable white-tailed deer (O. virginianus) increased 17.5-fold but moose remained unchanged. Wolf numbers also increased from approximately 6–11.5/1,000 km². Coincident with these changes, spatial overlap between wolf pack territories and caribou range was high relative to the mid-1990s. The high number of wolf locations in caribou range suggests that forays were not merely exploratory, but rather represented hunting forays and denning locations. Scat analysis indicated that wolf consumption of moose declined substantively during this time period, whereas use of deer increased markedly and deer replaced moose as the primary prey of wolves. Caribou increased 10-fold in the diet of wolves and caribou population trends in the region changed from stable to declining. Wolf use of beaver (Castor canadensis) increased since the mid-1990s. We suggest that recent declines in woodland caribou populations in the southerly extent of their range have occurred because high deer densities resulted in a numeric response by wolves and consequently higher incidental predation on caribou. Our results indicate that management actions to conserve caribou must now include deer in primary prey and wolf reduction programs. © 2010 The Wildlife Society     

Effects of large-scale removal of coyotes on pronghorn and mule deer productivity and abundance

We tested the hypothesis that predation by coyotes (Canis latrans) impacts pronghorn (Antilocapra americana) and mule deer (Odocoileus hemionus) populations. We did so by examining the effects of coyote removal on pronghorn and mule deer populations within 12 large areas (>10,500 km²) located in Wyoming and Utah during 2007 and 2008. Pronghorn productivity (fawn to adult female ratio) and abundance were positively correlated with the number of coyotes removed and removal effort (hours spent hunting coyotes from aircraft) although the correlation between pronghorn productivity and removal effort was not statistically significant (P = 0.08). Mule deer productivity and abundance were not correlated with either the number of coyotes removed or removal effort. Coyote removal conducted during the winter and spring provided greater benefit than removals conducted during the prior fall or summer. Our results suggest that coyote removal conducted over large areas increases fawn survival and abundance of pronghorn but not mule deer. © 2011 The Wildlife Society.     

Does Removing Coyotes for Livestock Protection Benefit Free-Ranging Ungulates?

Abstract: We studied the effects of coyote (Canis latrans) control for livestock protection on native ungulates during 2003 and 2004 on 7 sites in Utah and Colorado, USA, totaling over 1,900 km². We found no relationships between coyote control variables and offspring/female deer ratios. However, control effort (no. of hr spent aerial gunning for coyotes) and success (no. of coyotes taken) were positively correlated with numbers of mule deer (Odocoileus hemionus) and pronghorn (Antilocapra americana) observed per kilometer of transect. Our results suggest that coyote control for livestock protection may increase densities of mule deer and pronghorn in areas where it is conducted.     

INTROGRESSIVE HYBRIDIZATION AND NONCONCORDANT EVOLUTIONARY HISTORY OF MATERNAL AND PATERNAL LINEAGES IN NORTH AMERICAN DEER

Introgressive hybridization between mule deer (Odocoileus hemionus) and white-tailed deer (O. virginianus) was studied using sequence analysis of the paternally inherited, Y-linked, Zfy gene. The distribution of Zfy genotypes indicate that male white-tailed deer disperse into the range of mule deer and successfully breed with mule deer does. In western Texas, F₁ hybrids are rare, but a relatively high proportion of backcross individuals was observed. Phylogenetic analysis of Zfy among white-tailed, mule, and black-tailed deer was consistent with traditional systematic placement of the latter two being sister-taxa, whereas previous mtDNA studies suggested mule and white-tailed deer were sister taxa.     

Predicting the status of wild deer as hosts of <Emphasis Type="Italic">Mycobacterium bovis</Emphasis> infection in Britain

Control of livestock diseases can become complicated when wild animals are involved. The Eurasian badger (Meles meles) is considered the principle wildlife host of Mycobacterium bovis (which causes bovine tuberculosis, bTB) in Great Britain and Ireland, but wild deer have also been implicated. Whether wild deer are likely to perpetuate bTB in cattle depends on the exposure risks they pose, the mode of pathogen transmission, the distances over which the disease can be transported and whether they can maintain infection within their own populations independently of other sources. We evaluated the likely host status of each of four species of wild British deer (red, roe, fallow and Reeves' muntjac) and the badger across a range of densities typically observed in Britain by manipulating the reproductive number equation proposed by Anderson and May (1991). We estimate that roe deer almost certainly act as spillover hosts at densities lower than 30 km⁻², red deer below 16 km⁻², muntjac below 6 km⁻², fallow below 4 km⁻² and the badger below 2 km⁻². We also estimate that muntjac will almost certainly act as maintenance hosts at densities above 56 km⁻², fallow above 47 km⁻² and badgers above 24 km⁻². For densities between these values, we cannot be certain of the host status of these species, and for red and roe deer we cannot be certain of host status under most natural conditions typically experienced in parts of Britain experiencing high incidence of bTB in cattle. However, enhanced transmission rates resulting from artificially high densities such as might be experienced at supplementary feeding sites may be sufficient to promote independent maintenance of infection. We were not able to confidently assign host status to any species over a wide range of densities, but conclude that this is likely to reflect reality, where host status may be affected as much by, for example, demographic fluctuations as it is by population density. Our results imply densities below which populations of wild deer inhabiting cattle bTB hotspots ought to be maintained in order to control the possibility of them perpetuating the cycle of intra- and interspecific M. bovis transmission.     

Predator densities and white-tailed deer fawn survival

Predation is the dominant source of mortality for white-tailed deer (Odocoileus virginianus) <6 months old throughout North America. Yet, few white-tailed deer fawn survival studies have occurred in areas with 4 predator species or have considered concurrent densities of deer and predator species. We monitored survival and cause-specific mortality from birth to 6 months for 100 neonatal fawns during 2013–2015 in the Upper Peninsula of Michigan, USA, while simultaneously estimating population densities of deer, American black bear (Ursus americanus), coyote (Canis latrans), bobcat (Lynx rufus), and gray wolf (Canis lupus). We estimated fawn predation risk in response to sex, birth mass, and date of birth. Six-month fawn survival pooled among years was 36%, and fawn mortality risk was not related to birth mass, date of birth, or sex. Estimated mean annual deer and predator densities were 334 fawns/100 km², 25.9 black bear/100 km², 23.8 coyotes/100 km², 3.8 bobcat/100 km², and 2.8 wolves/100 km². Despite lower estimated per-individual kill rates, coyotes and black bears were the leading sources of fawn mortality because they had greater densities relative to bobcats and wolves. Our results indicate that the presence of more predator species in a system is not entirely additive in its effect on fawn survival. © The Wildlife Society, 2019     

Big cats at large: Density,structure, and spatio-temporal patterns of a leopard population free of anthropogenic mortality

Human impact is near pervasive across the planet and studies of wildlife populations free of anthropogenic mortality are increasingly scarce. This is particularly true for large carnivores that often compete with and, in turn, are killed by humans. Accordingly, the densities at which carnivore populations occur naturally, and their role in shaping and/or being shaped by natural processes, are frequently unknown. We undertook a camera-trap survey in the Sabi Sand Game Reserve (SSGR), South Africa, to examine the density, structure and spatio-temporal patterns of a leopard Panthera pardus population largely unaffected by anthropogenic mortality. Estimated population density based on spatial capture–recapture models was 11.8 ± 2.6 leopards/100 km². This is likely close to the upper density limit attainable by leopards, and can be attributed to high levels of protection (particularly, an absence of detrimental edge effects) and optimal habitat (in terms of prey availability and cover for hunting) within the SSGR. Although our spatio-temporal analyses indicated that leopard space use was modulated primarily by “bottom-up” forces, the population appeared to be self-regulating and at a threshold that is unlikely to change, irrespective of increases in prey abundance. Our study provides unique insight into a naturally-functioning carnivore population at its ecological carrying capacity. Such insight can potentially be used to assess the health of other leopard populations, inform conservation targets, and anticipate the outcomes of population recovery attempts.     

Population densities of Sulawesi crested black macaques (Macaca nigra) on Bacan and Sulawesi,Indonesia: Effects of habitat disturbance and hunting

Population surveys of Sulawesi crested black macaques (Macaca nigra) were conducted on the Indonesian islands of Sulawesi and Bacan in 1992–1994 to assess the status of natural populations and determine habitat and anthropogenic factors affecting their population densities. We surveyed five sites for primates, including undisturbed and disturbed habitats. Data were collected on habitat structure and composition at two undisturbed and one disturbed forest site in which the primates were surveyed. The highest density of macaques was found in primary forest at Gunung Sibela Nature Reserve on Bacan (170.3 individuals/km²). Population density in logged forest on Bacan was high but significantly less than primary forest (133.4 individuals/km²). The high density of crested black macaques in primary forest on Bacan is best explained by the high carrying capacity found in primary forest. The lower food quantity and quality of food resources found in logged forest correlated with lower primate densities compared to primary forest. However, the large population of macaques in logged forest demonstrates the conservation value of such forest. Densities on Sulawesi at Tangkoko-Batuangas-DuaSudara Nature Reserve (TBDS) showed a continuing decline since earlier surveys. Primate densities were highest near the protected center of Tangkoko Reserve (66.7 individuals/km²). The peripheral areas of Batuangas and DuaSudara, even though adjacent and continuous, showed lower population densities of 46.4 and 23.5 individuals/km², respectively. The best explanation for the continued decline of Macaca nigra populations at TBDS is hunting. Unless conservation measures are implemented immediately, M. nigra on Sulawesi risks extinction in the near future. Am. J. Primatol. 44:89–106, 1998. © 1998 Wiley-Liss, Inc.     

The effect of terrain and female density on survival of neonatal white‐tailed deer and mule deer fawns

Juvenile survival is a highly variable life‐history trait that is critical to population growth. Antipredator tactics, including an animal's use of its physical and social environment, are critical to juvenile survival. Here, we tested the hypothesis that habitat and social characteristics influence coyote (Canis latrans) predation on white‐tailed deer (Odocoileus virginianus) and mule deer (O. hemionus) fawns in similar ways during the neonatal period. This would contrast to winter when the habitat and social characteristics that provide the most safety for each species differ. We monitored seven cohorts of white‐tailed deer and mule deer fawns at a grassland study site in Alberta, Canada. We used logistic regression and a model selection procedure to determine how habitat characteristics, climatic conditions, and female density influenced fawn survival during the first 8 weeks of life. Fawn survival improved after springs with productive vegetation (high integrated Normalized Difference Vegetation Index values). Fawns that used steeper terrain were more likely to survive. Fawns of both species had improved survival in years with higher densities of mule deer females, but not with higher densities of white‐tailed deer females, as predicted if they benefit from protection by mule deer. Our results suggest that topographical variation is a critical resource for neonates of many ungulate species, even species like white‐tailed deer that use more gentle terrain when older. Further, our results raise the possibility that neonatal white‐tailed fawns may benefit from associating with mule deer females, which may contribute to the expansion of white‐tailed deer into areas occupied by mule deer.     

Mule Deer Migrations and Highway Underpass Usage in California,USA

Roadways may pose barriers to long-distance migrators such as some ungulates. Highway underpasses mitigate wildlife-vehicle collisions and can be an important management tool for protecting migration corridors. In northern California, 3 underpasses were built on United States Route 395 (Route 395) in Hallelujah Junction Wildlife Area (HJWA) in the 1970s for a migratory mule deer (Odocoileus hemionus) herd that had been negatively affected by highway traffic. To determine whether these underpasses were still reducing mule deer mortalities >40 years after construction, we investigated deer use of the underpasses from 2006–2019 using cameras, global positioning system (GPS) collars, and roadkill records. We used occupancy models, approximations of GPS-collared mule deer movement paths, and roadkill locations to estimate the highway crossing patterns of deer. From camera data, there was higher use of the underpasses by deer during migration (spring [Mar–Jun], fall [Oct–Dec]) than in summer (Jul–Sep), when only resident deer were present. Higher underpass usage occurred in the spring compared to fall migrations. Eleven of 21 GPS-collared migrating mule deer crossed Route 395. We estimated 30% of the crossings (by 7 of the 11 deer) occurred south of the underpasses where deer could easily access the highway because of short (1-m high) and deteriorating highway fencing. Roadkill data confirmed that deer-vehicle collisions were occurring south of the underpasses and at the underpasses. This was likely due to deteriorating infrastructure at the underpasses that allows wildlife access to the highway. Overall, our study indicated that although underpasses can provide safe passage for migratory deer decades (>40 yr) after their construction, deteriorating infrastructure such as fencing and gates can lead to wildlife mortalities on highways near underpasses. © 2021 The Wildlife Society.