Evidence of long-distance dispersal of a gray wolf from the Chernobyl Exclusion Zone

The Chernobyl Exclusion Zone (CEZ) is a ~?4300 km² area in Belarus and Ukraine that remains heavily contaminated with radiation from the nuclear accident of 1986. Long standing controversy persists on the fate of wildlife within the CEZ following human abandonment of the area. Human residency remains extremely sparse, and the CEZ has become a refuge for some populations of wildlife, including gray wolves (Canis lupus). Using GPS telemetry, we documented the first long-distance movements of a young (1–2 years) male wolf from the CEZ into the surrounding landscape. The wolf traveled 369 km from its home range center over a 21-day period in February 2015. In the 95 days prior to dispersal, the wolf maintained a home range of ~?28 km², with daily displacements rarely exceeding 5 km. With the onset of dispersal, daily displacement increased to a mean of 16.8 km. The dispersal of a young wolf is an important observation because it suggests that the CEZ may serve as a source for some wildlife populations outside of the CEZ, and raises questions about the potential spread of radiation-induced genetic mutations to populations in uncontaminated areas.     

The scavenger spyglass: how recruiting hunters to watch carrion boosts wildlife research

Hunters support scavengers with seasonal pulses of carrion. If those hunters also deploy remote cameras at kill sites, they could simultaneously contribute data to wildlife research while gaining first-hand knowledge of scavenger ecology. In 2018–2020, we recruited hunters to monitor carcasses and offal with remote cameras across western Montana, USA. We increased our sampling effort by also setting up cameras following successful elk (Cervus canadensis) hunts at a private ranch. Cameras recorded 19 scavenger species. Golden eagles (Aquila chrysaetos) appeared at 55% of sites, and 3 individuals wore auxiliary markers, demonstrating how hunters can augment efforts to detect tagged wildlife. Cameras also documented elusive predators (e.g., wolves [Canis lupus]) and a seasonality of scavenging among American black bears (Ursus americanus). At 42% of the sites, ≥1 cervid investigated the carrion within 1 m, a behavior that may transmit the prions associated with chronic wasting disease. Hunters are willing and competent citizen scientists that can help generate wildlife observations at a broad spatial scale.     

Sampling bias exaggerates a textbook example of a trophic cascade

Understanding trophic cascades in terrestrial wildlife communities is a major challenge because these systems are difficult to sample properly. We show how a tradition of non-random sampling has confounded this understanding in a textbook system (Yellowstone National Park) where carnivore [Canis lupus (wolf)] recovery is associated with a trophic cascade involving changes in herbivore [Cervus canadensis (elk)] behaviour and density that promote plant regeneration. Long-term data indicate a practice of sampling only the tallest young plants overestimated regeneration of overstory aspen (Populus tremuloides) by a factor of 4–7 compared to random sampling because it favoured plants taller than the preferred browsing height of elk and overlooked non-regenerating aspen stands. Random sampling described a trophic cascade, but it was weaker than the one that non-random sampling described. Our findings highlight the critical importance of basic sampling principles (e.g. randomisation) for achieving an accurate understanding of trophic cascades in terrestrial wildlife systems.     

Complex tactics in a dynamic large herbivore–carnivore spatiotemporal game

The spatiotemporal game between predators and prey is a fundamental process governing their distribution dynamics. Players may adopt different tactics as the associated costs and benefits change through time. Yet few studies have investigated the potentially simultaneous and dynamic nature of movement tactics used by both players. It is particularly unclear to what extent perceived predation risk mediates the fine‐scale distribution of large and dangerous prey, which are mostly driven by bottom–up, resource‐related processes. We built habitat use and movement models based on 10 years of monitoring GPS‐collared grey wolves Canis lupus and plains bison Bison bison bison in Prince Albert National Park, Canada, to investigate the predator–large prey game in a multi‐prey system. Bison did not underuse patches of high‐quality vegetation at any time during the seasonal cycle even though wolves were selectively patrolling these areas. Rather, in at least one season, bison engaged in complex tactics comprised of proactive responses to the long‐term distribution (risky places) and reactive responses to the immediate proximity (risky times) of their opponent. In summer–autumn, bison reduced the time spent in food‐rich patches as both the long‐term use and the immediate proximity of wolves increased. By demonstrating that wolf distribution triggers patch abandonment by bison, we provide a key element in support of the shell game hypothesis – where prey move constantly to avoid predators attempting to anticipate their location. In winter, a season of relatively high energetic stress, bison no longer abandoned food‐rich patches as predation risk increased, while no bison responses to wolves were observed in spring–summer. Our work demonstrates the highly dynamic and complex nature of the predator–large prey spatiotemporal game, a key trait‐mediated mechanism by which trophic interactions structure ecological communities.     

Winter predation patterns of wolves in Northwestern Wyoming

Wolf (Canis lupus) diets and potential effects on prey have been a prominent subject of interest to wildlife researchers and managers since reintroduction into Yellowstone National Park, Wyoming, USA, in 1995 and 1996. Post-reintroduction, wolves expanded south and recolonized areas in the southern Yellowstone ecosystem. Elk (Cervus elaphus) in this area are supplementally fed during winter (Dec–Mar) at state-managed feedgrounds, resulting in high-density congregations of elk. From December to March 2000–2007, we determined the winter predation patterns of wolves by examining the remains of 289 wolf kills on 3 state-managed feedgrounds and adjacent winter range near Jackson, Wyoming. During winters 2002–2005, we also monitored the movements of radio-collared elk on feedgrounds to describe the response of elk to the presence of wolf kills. Thirty-seven percent (n = 106) of kills were located on elk feedgrounds where elk composition included 49% calves, 42% adult females, 5% adult males, and 5% unknown. Sixty-three percent (n = 183) of kills were located on winter range adjacent to feedgrounds and prey species consisted of 90% elk (38% calves, 35% adult females, 24% adult males, 2% unknown), 9% moose (Alces alces; 13% calves, 69% adult females, 6% adult males, 1% unknown), 1% mule deer (Odocoileus hemionus; 1 fawn, 1 adult female), and 0.5% adult female bison (Bison bison). Mean age of elk killed on feedgrounds was 4.2 years (range = 0–20) and 4.6 years (range = 0–23) on winter range. Calves were selected more than available in most years with female elk killed less than expected. Adult males were killed more than expected in 2005–2007. Eighty-eight percent (n = 198) of the time elk remained on the feedground even when wolves made a kill. Less commonly, elk left the feedground, gathered in larger herds on adjacent feedgrounds absent of wolves, and returned within a few days (6%, n = 13) or left the feedground for another feedground and did not return for the rest of the winter (6%; n = 14). Elk were less likely to leave feedgrounds in the presence of a wolf kill when there were more elk on that feedground. Elk left feedgrounds with greater topography and tree cover (Alkali and Fish Creek) and gathered on the flat, open feedgrounds (Patrol Cabin) more frequently than they left flat, open feedgrounds for feedgrounds with greater topography and tree cover. Our results indicate wolves in our study area primarily preyed on elk and exhibited a strong preference for elk calves. High-density concentrations of elk on feedgrounds will continue to be an attractant for wolves. Although elk leave feedgrounds for reasons other than wolf presence, any displacement of elk from feedgrounds due to wolves will be temporary. State managers have the ability to alter management strategies (e.g., increasing wolf harvest, phasing out elk feeding, increasing the intensity of elk feeding) in an effort to affect predator-prey relationships. © 2019 The Wildlife Society.     

Influence of Group Size on the Success of Wolves Hunting Bison

An intriguing aspect of social foraging behaviour is that large groups are often no better at capturing prey than are small groups, a pattern that has been attributed to diminished cooperation (i.e., free riding) in large groups. Although this suggests the formation of large groups is unrelated to prey capture, little is known about cooperation in large groups that hunt hard-to-catch prey. Here, we used direct observations of Yellowstone wolves (Canis lupus) hunting their most formidable prey, bison (Bison bison), to test the hypothesis that large groups are more cooperative when hunting difficult prey. We quantified the relationship between capture success and wolf group size, and compared it to previously reported results for Yellowstone wolves hunting elk (Cervus elaphus), a prey that was, on average, 3 times easier to capture than bison. Whereas improvement in elk capture success levelled off at 2–6 wolves, bison capture success levelled off at 9–13 wolves with evidence that it continued to increase beyond 13 wolves. These results are consistent with the hypothesis that hunters in large groups are more cooperative when hunting more formidable prey. Improved ability to capture formidable prey could therefore promote the formation and maintenance of large predator groups, particularly among predators that specialize on such prey.     

Dispersal Behavior and the Connectivity Between Wolf Populations in Northern Europe

ABSTRACT The isolated gray wolf (Canis lupus) population of the Scandinavian Peninsular is suffering from inbreeding depression. We studied dispersal of 35 wolves fitted with very high frequency (20) or Global Positioning System—global system for mobile (15) radiocollars in the neighboring Finnish wolf population. The growing wolf population in Finland has high numbers of dispersing individuals that could potentially disperse into the Scandinavian population. About half (53%) of the dispersing wolves moved total distances that could have reached the Scandinavian population if they had been straight-line moves, but because of the irregular pattern of movements, we detected no wolves successfully dispersing to the Scandinavian population. Dispersal to the Scandinavian population was also limited by high mortality of wolves in reindeer (Rangifer tarandus) management areas and by dispersal to Bothnian Bay at times of the year when ice was not present. We suggest that when a small wolf population is separated from source populations by distance, barriers, and human exploitation, wildlife managers could promote the population's viability by limiting harvest in the peripheral areas or by introducing wolves from the source population.     

Multiscale wolf predation risk for elk: does migration reduce risk?

While migration is hypothesized to reduce predation risk for ungulates, there have been few direct empirical tests of this hypothesis. Furthermore, few studies examined multiscale predation risk avoidance by migrant ungulates, yet recent research reveals that predator–prey interactions occur at multiple scales. We test the predation risk reduction hypothesis at two spatial scales in a partially migratory elk (Cervus elaphus) population by comparing exposure of migrant and resident elk to wolf (Canis lupus) predation risk. We used GPS and VHF telemetry data collected from 67 migrant and 44 resident elk over the summers of 2002–2004 in and adjacent to Banff National Park (BNP), Canada. We used wolf GPS and VHF telemetry data to estimate predation risk as a function of the relative probability of wolf occurrence weighted by a spatial density model that adjusted for varying pack sizes. We validated the predation risk model using independent data on wolf-killed elk, and showed that combining wolf presence and spatial density best predicted where an elk was likely to be killed. Predation risk on summer ranges of migrant elk was reduced by 70% compared to within resident elk summer ranges. Because wolves avoided areas near high human activity, however, fine-scale selection by resident elk for areas near high human activity reduced their predation risk exposure to only 15% higher than migrants, a difference significant in only one of three summers. Finally, during actual migration, elk were exposed to 1.7 times more predation risk than residents, even though migration was rapid. Our results support the hypothesis that large-scale migrations can reduce predation. However, we also show that where small-scale spatial variation in predation risk exists, nonmigratory elk may equally reduce predation risk as effectively as migrants under some circumstances.     

Boreal predator co‐occurrences reveal shared use of seismic lines in a working landscape

Interspecific interactions are an integral aspect of ecosystem functioning that may be disrupted in an increasingly anthropocentric world. Industrial landscape change creates a novel playing field on which these interactions take place, and a key question for wildlife managers is whether and how species are able to coexist in such working landscapes. Using camera traps deployed in northern Alberta, we surveyed boreal predators to determine whether interspecific interactions affected occurrences of black bears (Ursus americanus), coyotes (Canis latrans), and lynx (Lynx canadensis) within a landscape disturbed by networks of seismic lines (corridors cut for seismic exploration of oil and gas reserves). We tested hypotheses of species interactions across one spatial‐only and two spatiotemporal (daily and weekly) scales. Specifically, we hypothesized that (1) predators avoid competition with the apex predator, gray wolf (Canis lupus), (2) they avoid competition with each other as intraguild competitors, and (3) they overlap with their prey. All three predators overlapped with wolves on at least one scale, although models at the daily and weekly scale had substantial unexplained variance. None of the predators showed avoidance of intraguild competitors or overlap with prey. These results show patterns in predator space use that are consistent with both facilitative interactions or shared responses to unmeasured ecological cues. Our study provides insight into how predator species use the working boreal landscape in relation to each other, and highlights that predator management may indirectly influence multiple species through their interactions.     

Wolf population dynamics in the U.S. Northern Rocky Mountains are affected by recruitment and human-caused mortality

Reliable analyses can help wildlife managers make good decisions, which are particularly critical for controversial decisions such as wolf (Canis lupus) harvest. Creel and Rotella (2010) recently predicted substantial population declines in Montana wolf populations due to harvest, in contrast to predictions made by Montana Fish, Wildlife and Parks (MFWP). We replicated their analyses considering only those years in which field monitoring was consistent, and we considered the effect of annual variation in recruitment on wolf population growth. Rather than assuming constant rates, we used model selection methods to evaluate and incorporate models of factors driving recruitment and human-caused mortality rates in wolf populations in the Northern Rocky Mountains. Using data from 27 area-years of intensive wolf monitoring, we show that variation in both recruitment and human-caused mortality affect annual wolf population growth rates and that human-caused mortality rates have increased with the sizes of wolf populations. We document that recruitment rates have decreased over time, and we speculate that rates have decreased with increasing population sizes and/or that the ability of current field resources to document recruitment rates has recently become less successful as the number of wolves in the region has increased. Estimates of positive wolf population growth in Montana from our top models are consistent with field observations and estimates previously made by MFWP for 2008–2010, whereas the predictions for declining wolf populations of Creel and Rotella (2010) are not. Familiarity with limitations of raw data, obtained first-hand or through consultation with scientists who collected the data, helps generate more reliable inferences and conclusions in analyses of publicly available datasets. Additionally, development of efficient monitoring methods for wolves is a pressing need, so that analyses such as ours will be possible in future years when fewer resources will be available for monitoring. © 2011 The Wildlife Society.     

Coexistence of wolves and humans in a densely populated region (Lower Saxony,Germany)

Since the first sporadic occurrences of grey wolves (Canis lupus) west of the Polish border in 1996, wolves have shown a rapid population recovery in Germany. Wolves are known to avoid people and wolf attacks on humans are very rare worldwide. However, the subjectively perceived threat is considerable, especially as food-conditioned habituation to humans occurs sporadically. Lower Saxony (Germany) has an exceedingly higher human population density than most other regions with territorial wolves; thus, the potential for human–wolf conflicts is higher. Using hunters’ wildlife survey data from 455 municipalities and two years (2014–2015) and data from the official wolf monitoring (557 confirmed wolf presences and 500 background points) collected between 2012–2015, grey wolf habitat selection was modelled using generalized additive models with respect to human population density, road density, forest cover and roe deer density. Moreover, we tested whether habitat use changed in response to human population and road density between 2012/2013 and 2014/2015.Wolves showed a preference for areas of low road density. Human population density was less important as a covariate in the model of the survey data. Areas with higher prey abundance (5–10 roe deer/km²) and areas with >20% forest cover were preferred wolf habitats. Wolves were mostly restricted to areas with the lowest road and human population densities. However, between the two time periods, avoidance of human density decreased significantly.Recolonization of Germany is still in its early stages and it is unclear where this process will halt. To-date authorities mainly concentrate on monitoring measures. However, to avoid conflict, recolonization will require more stringent management of wolf populations and an improved information strategy for rural populations.     

Influences on mammals frequency of use of small bridges and culverts along the Qinghai–Tibet railway,China

Understanding the use of small bridges and culverts by wildlife to cross the Qinghai–Tibet railway will aid in the design of wildlife crossing structures for similar transportation infrastructure. From 2014 to 2016, 36 infrared cameras were placed inside 14 small bridges and 11 culverts along the Qinghai–Tibet railway to determine the structures’ effectiveness as wildlife passages. Thirteen species of mammals were found to use the small bridges and culverts to cross the railway. The crossing rates for all mammals were significantly higher for small bridges than for culverts. Tibetan antelope (Pantholops hodgsonii), Tibetan gazelle (Procapra picticaudata), kiang (Equus kiang), and wild yak (Bos mutus) preferred small bridges over culverts to cross the railway. In contrast, mountain weasel (Mustela altaica) and Asian badger (Meles leucurus) preferred culverts to cross the railway. The crossing rates of all mammals, particularly Tibetan gazelle and woolly hare, were positively influenced by structure width. Structure height had a positive influence on wild yak, but structure length had a negative influence on kiang. The distance to the highway had a positive influence on the crossing rates of all mammals, particularly wild yak and woolly hare. Human use of the structures had no influence on the crossings of most mammals except for common wolf. We suggest that road design schemes include large and open crossing structures to benefit most species with limitations on human activities near wildlife passages.     

Problems with studying wolf predation on small prey in summer via global positioning system collars

We attempted to study predation on various-sized prey by a male and female wolf (Canis lupus) with global positioning system (GPS) collars programmed to acquire locations every 10 min in the Superior National Forest of Minnesota. During May to August 2007, we investigated 147 clusters of locations (31% of the total) and found evidence of predation on a white-tailed deer (Odocoileus virginianus) fawn and yearling, a beaver (Castor canadensis), ruffed grouse (Bonasa umbellus), and fisher (Martes pennanti) and scavenging on a road-killed deer and other carrion. However, we missed finding many prey items and discuss the problems associated with trying to conduct such a study.     

Genetic nature of eastern wolves: Past, present and future

Eastern North American wolves have long been recognized as morphologically distinct from both coyotes and gray wolves. This has led to questions regarding their origins and taxonomic status. Eastern wolves are mainly viewed as: (1) a smaller subspecies of gray wolf (Canis lupus lycaon), potentially the result of historical hybridization between gray wolves (C. lupus) and red wolves (C. rufus), (2) a hybrid, the result of gray wolf (C. lupus) and coyote (C. latrans) interbreeding, or (3) a distinct species, C. lycaon, closely related to the red wolf (C. rufus). Although debate persists, recent molecular studies suggest that the eastern wolf is not a gray wolf subspecies, nor the result of gray wolf/coyote hybridization. Eastern wolves were more likely a distinct species, C. lycaon, prior to the eastward spread of coyotes in the late 1800s. However, contemporary interbreeding exits between C. lycaon to both C. lupus and C. latrans over much of its present range complicating its present taxonomic characterization. While hybridization may be reducing the taxonomic distinctiveness of C. lycaon, it should not necessarily be viewed as negative influence. Hybridization may be enhancing the adaptive potential of eastern wolves, allowing them to more effectively exploit available resources in rapidly changing environments.     

Balancing costs and confidence: volunteer-provided point observations,GPS telemetry and the genetic monitoring of Finland’s wolves

Reliable and updated population estimates are a necessity for the successful conservation and management of endangered animal populations. Citizen science has become increasingly important in wildlife monitoring and is an attractive concept due to its low costs. However, the applicability of citizen science in the monitoring of large carnivore populations is questionable for various reasons, including the difficulties associated with species identification. In Finland, where estimates of the fragmentary wolf (Canis lupus) population have varied between 140 and 280 animals in the last 10 years, population monitoring has been based on volunteer-provided data and telemetry. To compensate for a recent decrease in the proportion of territories with boundaries mapped through telemetry, a non-invasive genetics project was launched in 2016. We evaluated the experiences from this project, in which non-invasive genetic techniques were, for the first time, widely used (n?=?22 territories, 54% of the 41 apparent territories hosted by wolves in March 2017) to determine the post-hunting population estimate in early March 2017, before pack sizes began to decrease due to dispersal by sub-adult wolves. In territories where the non-invasive genetic monitoring was executed in the winter of 2016/2017, the pack sizes resulting from the volunteer-provided observations and the genetic analyses were highly correlated. By using the most typical variation in the proportion of non-residents in the wolf populations (6–20%, Fuller et al. 2003), we derived a population estimate of 150–178 wolves for early March 2016, and, by considering the known mortality during the study period, a minimum estimate of 204–234 wolves for early Aug. 2016. Despite its high costs, we recommend that non-invasive genetic monitoring should cover all known territories supporting Finland’s small and exploited wolf population. This much costlier protocol may be unrealistic in Finland. In any case, there is a need for more genetic sampling to test the quality of volunteer-provided data.     

Territory size of wolves Canis lupus: linking local (Białowieża Primeval Forest, Poland) and Holarctic-scale patterns

Factors affecting territory size in wolves Canis lupus were studied at 2 scales, the local population (Bia?owie?a Primeval Forest (BPF), eastern Poland) and the geographic range of species (literature review from 14 localities in the Holarctic). Four packs of wolves were studied by radio‐tracking in BPF from 1994 to 1999. The annual territories of packs (Minimum convex polygons with 95% of locations) averaged 201 km² (SD 63, range 116–310). Core areas of territories (50% MCP) covered from 14 to 78 km² (mean 35). Territory sizes and core areas both were negatively correlated to the encounter rates of ungulates (mean number of ungulates seen per unit time spent in the forest by human observers). Pack size (3–8 wolves) did not influence territory size. Home ranges of individual wolves from the same pack varied with season as well as the age, sex, and reproductive status of the wolf. Review of literature from North America and Europe (42–66^oN), showed that latitude and prey biomass were essential factors shaping the biogeographic variation in wolf territory size. Territories increased with latitude and declined with growing biomass of prey. The analysis showed that latitude acted partly independently of the south–north gradient in prey abundance. At similar standing crop of ungulate biomass (100 kg km^?2), wolf territories would average 140 km² at 40^oN, 370 km² at 50^oN, and 950 km² at 60^oN. Pack size was larger at northern latitudes, but the increase did not keep pace with enlargement of territories. Within‐territory density of wolves declined from 2.5–3 wolves 100 km^?2 at 40–45^oN to 0.7 wolves 100 km^?2 at 60^oN. Our analyses documented similarities regarding the role of prey resources in shaping wolf territoriality at the different scales. Furthermore, a macroecological approach revealed additional factors affecting wolf territory size that were not emergent from knowledge of local population.     

From a Howling Wilderness to Howling Safaris: Science,Policy and Red Wolves in the American South

This article details the complex natural and cultural history of red wolf (Canis rufus) restoration in the American South. The decisions and methods utilized in the red wolf’s recovery after 1960 were unprecedented and creative but not geographically limited. The federal red wolf recovery experiment highlights the debate over what constitutes a species in a dynamic world, and the practical challenges and unexpected results in endangered species management in peopled landscapes. This wildlife restoration story illustrates not only the “hands-on” management role humans played, and continue to play, but also reveals cultural assumptions about what constitutes a “wild” wolf and about the necessity of wilderness. The red wolf recovery project provides constructive lessons for future species restoration involving flora and fauna on public and private land, and demonstrates human and animal engagement in the making of nature and culture.     

Testing Global Positioning System Telemetry to Study Wolf Predation on Deer Fawns

ABSTRACT We conducted a pilot study to test the usefulness of Global Positioning System (GPS) collars for investigating wolf (Canis lupus) predation on white-tailed deer (Odocoileus virginianus) fawns. Using GPS collars with short location-attempt intervals on 5 wolves and 5 deer during summers 2002–2004 in northeastern Minnesota, USA, demonstrated how this approach could provide new insights into wolf hunting behavior of fawns. For example, a wolf traveled ≥1.5–3.0 km and spent 20–22 hours in the immediate vicinity of known fawn kill sites and ≥0.7 km and 8.3 hours at scavenging sites. Wolf travel paths indicated that wolves intentionally traveled into deer summer ranges, traveled ≥0.7–4.2 km in such ranges, and spent <1–22 hours per visit. Each pair of 3 GPS-collared wolf pack members were located together for ≤6% of potential locations. From GPS collar data, we estimated that each deer summer range in a pack territory containing 5 wolves ≥1 year old and hunting individually would be visited by a wolf on average every 3–5 days. This approach holds great potential for investigating summer hunting behavior of wolves in areas where direct observation is impractical or impossible.     

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     

Activity patterns of gray wolves housed in small vs. large enclosures

Free-ranging gray wolves (Canis lupus) generally inhabit large home ranges, yet they are housed in a variety of restricted spaces when in captivity. There is continual debate as to whether space restrictions alter a wolf's behavior. The purpose of these studies was to remotely measure and then compare the amount and frequency of activity of gray wolves housed in small, artificial enclosures vs. large, more natural enclosures. Test animals comprised three adult wolves housed in kennels and three and four wolves housed in separate natural enclosures. Kenneled wolves had 2.8 m² of surface area per wolf, and wolves in natural enclosures had 466.6 m² (South Pack) and 349.9 m² (North Pack) per wolf. Wolves were fitted with radiotelemetry collars containing activity sensors. Activity data were recorded every 20 min for 57 continuous hr. The amount of activity for each wolf was calculated using areas under the curve (AUCs), and the frequency of activity was analyzed by spectral analysis. There was no difference (P ≥ 0.22) in AUCs between kenneled wolves (1.399 ± 0.214 x 10⁵ radians) and South Pack wolves (1.564 ± 0.139 X 10⁵ radians) or North Pack wolves (1.617 ± 0.192 x 10⁵ radians). All three groups had similar peak spectral values at frequencies that were close to daily cycles (i.e., ω = 0.12–0.17 cycles per unit time). Peaks in coherence near the dominant spectral frequency were most significant between the natural enclosures and the least significant between the kenneled wolves and the South Pack wolves. Based on these criteria of activity and under these circumstances, enclosure size appeared to have no effect on wolf activity. However, small sample sizes and variation in the data do not make these results definitive. © 1996 Wiley-Liss, Inc.