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American marten (Martes americana) in Interior Alaska are at the northwestern limit of their North American range. To investigate factors that may be associated with reproduction we determined the cementum age and the presence or absence of blastocysts in 118 female martens for 3 years (2012, 2014, and 2016) in two regions. For each marten we collected fur samples and measured steroid hormone concentrations (cortisol, testosterone, and progesterone) and stable isotopes (δ15N and δ13C values, a proxy for diet). These parameters reflect the diet and endocrine activity between June and October when fur is grown. We also collected two claws from a subset of 39 female marten from one region in 2012 and 2014. Progesterone concentrations were measured in one whole claw and from a second claw divided into proximal (recent growth) and distal sections. Differences in the probability of blastocysts being present were associated with geographic region and sample year suggesting that reproduction in female marten varies on a fine scale. We found the that presence of blastocysts was positively associated with marten age and δ15N values in fur but negatively associated with fur cortisol concentrations. These findings suggest that the likelihood a female marten will reproduce in a given year is influenced, in part, by the proportion of protein in their diet and stressors encountered during late summer and fall, months before active gestation begins.

Lycaon pictus (Temminck, 1820), the African wild dog, is a moderately sized carnivore with dog-like appearance and irregularly mottled black, yellow-brown, and white pelage. It has a head–body length of 76–112 cm, tail length of 30–41 cm, shoulder height of 61–78 cm, and body weight of 17–36 kg. Lycaon pictus has four toes on each foot, differentiating it from other canids; is the only extant species within the genus with no subspecies; and is unlikely to be confused with any other canid. Lycaon pictus was once widespread throughout sub-Saharan Africa inhabiting nearly all environments and now inhabits grasslands, montane savanna, and open woodlands. Lycaon pictus is recognized as “Endangered” (EN) by the U.S. Fish and Wildlife Service and the International Union for Conservation of Nature.

Quantifying a fundamental life history event like parturition for any species is important both for wildlife management and research purposes. Surveys to estimate reproductive success for large mammals are typically done by visual observations on the ground or from the air and are time consuming, expensive and labor intensive particularly when conducted in remote locations. An alternative to visual verification is remote monitoring of animal movement and locations which can identify and link movement behavior to different types of life history events, such as parturition. We used GPS locations of a large ungulate (moose) to identify a specific behavioral change in the movement pattern that would indicate a calving event. From these data we applied three methods, one of which is a novel technique, to search for localized movement patterns that characterize a calving event for female moose in Sweden (n = 60 moose-years, ground observations) and Alaska (n = 49 moose-years, aerial observations). The three methods include a computerized visual method using Tracking Analyst® (TA), a rolling window minimum convex polygon (rMCP), and behavioral change point analysis (BCPA), all of which provided nearly identical results. BCPA confirmed lack of a parturition date for 100% of the animals that were never observed with a calf, whereas the rMCP method yielded 1 false positive. For Sweden, parturition dates inferred using rMCP agreed exactly or ±1 day with the dates inferred using BCPA for 98% moose-years whereas TA vs BCPA and rMCP agreed 98% and 100% respectively; for Alaska parturition dates estimated from rMCP and BCPA agreed equally at 94%. In this study we showed that evaluation of wildlife movement patterns from remote monitoring can lead to increased precision and understanding of parturition with minimal bias from neonatal mortality, in addition to understanding spatiotemporal distribution, resource selection, and other behaviors.

Ecological “big data” Human activities are rapidly altering the natural world. Nowhere is this more evident, perhaps, than in the Arctic, yet this region remains one of the most remote and difficult to study. Researchers have increasingly relied on animal tracking data in these regions to understand individual species' responses, but if we want to understand larger-scale change, we need to integrate our understanding across species. Davidson et al. introduce an open-source data archive that currently hosts more than 15 million location data points across 96 species and use it to show distinct climate change responses across species. Such ecological “big data” can lead to a wider understanding of change. Science , this issue p. 712

Wildlife managers in the 21st century are challenged to maintain balance for wildlife and human use of the landscape. Because mountain lion (Puma concolor) habitat is often adjacent to urbanization in Arizona, mountain lions are ideal models to examine how human alteration of habitats influences life-history characteristics. We quantified mountain lion home-range characteristics and selection of vegetative associations in central and southern Arizona. We calculated 95% and 50% fixed kernel home ranges for eight female and 21 male mountain lions radiocollared in Payson, Prescott, and Tucson, Arizona, from August 2005 through August 2008. We assessed use of vegetative associations and urban areas within the study area (second order) and within the home range (third order). At both levels of selection at all study sites, mountain lions avoided human-dominated landscapes. At second-order selection, mountain lions preferred woodland habitat in Tucson and Prescott and chaparral in Payson. At the third order, lions in Tucson and Payson selected riparian and chaparral in Prescott. Season, mountain lion mass, and ungulate density had no effect on the size of home ranges. Home-range sizes for resident males ranged from 5,286 to 83,859 ha; transient males covered up to 409,195 ha. Home ranges for females ranged from 2,860 to 21,772 ha. Intensive development and conversion of large open spaces to small properties and subdivisions has caused increased loss, fragmentation, and encroachment into mountain lion habitat. Preserving natural landscapes for access to habitat patches is important in maintaining connectivity to ensure viable populations.

Considered as absent throughout Scandinavia for >100 years, wolves (Canis lupus) have recently naturally recolonized south-central Sweden. This recolonization has provided an opportunity to study behavioral responses of moose (Alces alces) to wolves. We used satellite telemetry locations from collared moose and wolves to determine whether moose habitat use was affected by predation risk based on wolf use distributions. Moose habitat use was influenced by reproductive status and time of day and showed a different selection pattern between winter and summer, but there was weak evidence that moose habitat use depended on predation risk. The seemingly weak response may have several underlying explanations that are not mutually exclusive from the long term absence of non-human predation pressure: intensive harvest by humans during the last century is more important than wolf predation as an influence on moose behavior; moose have not adapted to recolonizing wolves; and responses may include other behavioral adaptations or occur at finer temporal and spatial levels than investigated.

We used camera trapping in conjunction with a spatial explicit capture–recapture model to estimate striped hyena (Hyaena hyaena) density and occupancy models to investigate factors affecting striped hyena detection probabilities in Ranthambhore Tiger Reserve (RTR), Rajasthan, India. A sampling effort of 4,450 trap days/nights over 75 days yield 68 photo captures of 21 unique striped hyenas (based on individual markings and visual identification); the estimated striped hyena density was 5.49 ± 1.27 individuals/100 km2. Results of our occupancy model suggested that a rugged terrain is an important factor that influences striped hyena detection probability. Correlation with striped hyena detection with human settlement provides evidence of social tolerance of striped hyena towards humans, and more occurrence of resources allowed coexistence of hyena in a human-dominated landscape. This elasticity (inhabited areas close to humans) demonstrated by striped hyenas is an exception among carnivore communities living in this semi-arid habitat.

Numerous forest birds benefit from woodpecker presence or have similar habitat requirements. Monitoring populations of forest woodpeckers can be useful for management decisions regarding these and other forest species. Usefulness of monitoring efforts depends on methods used and the quality of resulting parameter estimates. Estimating the proportion of area occupied by a species can be an attractive and affordable alternative to abundance or survival estimates. The purpose of this study was to assess the distribution and area of occupancy for pileated woodpeckers (Drycopus pileatus) and American three-toed woodpeckers (Picoides dorsalis) in north-central Idaho, and to compare occupancy estimates using silent point counts, playback surveys, and playback surveys that incorporated estimates of detection probability (p). We used a hierarchical multiscale framework that allowed estimation of occupancy at two spatial scales and applied a removal design such that repeat visits to sampling stations was not necessary to estimate p. The initial naïve estimate of occupancy (using presence–absence data) for pileated woodpecker was 0.39, which increased to 0.59 using playback surveys. The corrected estimate of occupancy at the 1-km2 unit scale was 0.70. The naïve estimates of occupancy for American three-toed woodpeckers using silent point counts and playback surveys were 0.14 and 0.34, respectively. The unbiased estimate of occupancy at the 1-km2 unit scale was 0.71. Detection probabilities are known to vary spatially and temporally for numerous reasons. Thus, comparisons of naïve estimates of occupancy to monitor forest woodpeckers would be imprudent and could lead to poor management decisions. We recommend incorporating detection probability for monitoring wildlife species and show how this can be done within a single sampling framework for species that utilize the landscape at disparate scales.

Background Predation risk is a primary motivator for prey to congregate in larger groups. A large group can be beneficial to detect predators, share predation risk among individuals and cause confusion for an attacking predator. However, forming large groups also has disadvantages like higher detection and attack rates of predators or interspecific competition. With the current recolonization of wolves (Canis lupus) in Scandinavia, we studied whether moose (Alces alces) respond by changing grouping behaviour as an anti-predatory strategy and that this change should be related to the duration of wolf presence within the local moose population. In particular, as females with calves are most vulnerable to predation risk, they should be more likely to alter behaviour. Methods To study grouping behaviour, we used aerial observations of moose (n = 1335, where each observation included one or several moose) inside and outside wolf territories. Results Moose mostly stayed solitary or in small groups (82% of the observations consisted of less than three adult moose), and this behavior was independent of wolf presence. The results did not provide unequivocal support for our main hypothesis of an overall change in grouping behaviour in the moose population in response to wolf presence. Other variables such as moose density, snow depth and adult sex ratio of the group were overall more influential on grouping behaviour. However, the results showed a sex specific difference in social grouping in relation to wolf presence where males tended to form larger groups inside as compared to outside wolf territories. For male moose, population- and environmentally related variables were also important for the pattern of grouping. Conclusions The results did not give support for that wolf recolonization has resulted in an overall change in moose grouping behaviour. If indeed wolf-induced effects do exist, they may be difficult to discern because the effects from moose population and environmental factors may be stronger than any change in anti-predator behaviour. Our results thereby suggest that caution should be taken as to generalize about the effects of returning predators on the grouping behaviour of their prey. Electronic supplementary material The online version of this article (doi:10.1186/s12983-017-0195-z) contains supplementary material, which is available to authorized users.

Migration is an important component of the life history of many animals, but persistence of large-scale terrestrial migrations is being challenged by environmental changes that fragment habitats and create obstacles to animal movements. In northern Alaska, the Central Arctic herd (CAH) of barren-ground caribou (Rangifer tarandus granti) is known to migrate over large distances, but the herd's seasonal distributions and migratory movements are not well documented. From 2003-2007, we used GPS radio-collars to determine seasonal ranges and migration routes of 54 female caribou from the CAH. We calculated Brownian bridges to model fall and spring migrations for each year and used the mean of these over all 4 years to identify areas that were used repeatedly. Annual estimates of sizes of seasonal ranges determined by 90% fixed kernel utilization distributions were similar between summer and winter (X̅ = 27,929 SE = 1,064 and X̅ = 26,585 SE = 4912 km2, respectively). Overlap between consecutive summer and winter ranges varied from 3.3-18.3%. Percent overlap between summer ranges used during consecutive years (X̅ = 62.4% SE = 3.7%) was higher than for winter ranges (X̅ = 42.8% SE = 5.9%). Caribou used multiple migration routes each year, but some areas were used by caribou during all years, suggesting that these areas should be managed to allow for continued utilization by caribou. Restoring migration routes after they have been disturbed or fragmented is challenging. However, prior knowledge of movements and threats may facilitate maintenance of migratory paths and seasonal ranges necessary for long-term persistence of migratory species.

In a predator–prey system, prey species may adapt to the presence of predators with behavioral changes such as increased vigilance, shifting habitats, or changes in their mobility. In North America, moose (Alces alces) have shown behavioral adaptations to presence of predators, but such antipredator behavioral responses have not yet been found in Scandinavian moose in response to the recolonization of wolves (Canis lupus). We studied travel speed and direction of movement of GPS‐collared female moose (n = 26) in relation to spatiotemporal differences in wolf predation risk, reproductive status, and time of year. Travel speed was highest during the calving (May–July) and postcalving (August–October) seasons and was lower for females with calves than females without calves. Similarly, time of year and reproductive status affected the direction of movement, as more concentrated movement was observed for females with calves at heel, during the calving season. We did not find support for that wolf predation risk was an important factor affecting moose travel speed or direction of movement. Likely causal factors for the weak effect of wolf predation risk on mobility of moose include high moose‐to‐wolf ratio and intensive hunter harvest of the moose population during the past century.

An understanding of the prevalence of diseases in free‐ranging populations of felids is limited, and there is even less known about the overall health and diseases of wild felids that inhabit or utilize urban areas. We collected serum samples from 9 radiocollared mountain lions (Puma concolor) in the mountains surrounding Tucson, Arizona, USA, from August 2005 to August 2008. We tested serum samples for evidence of exposure to 10 feline viruses: Feline Calicivirus (FCV), Feline Herpesvirus, Feline Enteric Coronavirus, Feline Syncytial Virus–Feline Foamy Virus, Feline Infectious Peritonitis, Feline Immunodeficiency Virus, Feline Panleukopenia Virus (FPLV), Feline Leukemia Virus, Canine Distemper Virus (CDV), and Toxoplasma gondii. The highest prevalences of exposure were: T. gondii (8/9), FPLV (7/9), and FCV (6/9). One male was seropositive for CDV, T. gondii, and FPLV. Mountain lions inhabiting smaller fragmented landscapes and urban areas have more contact with other felids and domesticated animals. Frequent contact among mountain lions, other felids, and domesticated animals can lead to higher risk of exposure and facilitate the spread of the disease from animal to animal. © 2012 The Wildlife Society.

Spatial and temporal interactions among individual members of populations can have direct applications to habitat management of mountain lions (Puma concolor). Our objectives were to evaluate home range overlap and spatial/temporal use of overlap zones (OZ) of mountain lions in Arizona. We incorporated spatial data with genetic analyses to assess relatedness between mountain lions with overlapping home ranges. We recorded the space use patterns of 29 radio-collared mountain lions in Arizona from August 2005 to August 2008. We genotyped 28 mountain lions and estimated the degree of relatedness among individuals. For 26 pairs of temporally overlapping mountain lions, 18 overlapped spatially and temporally and eight had corresponding genetic information. Home range overlap ranged from 1.18% to 46.38% ( $$ \overline x = {\text{24}}.{\text{43}} $$ , SE = 2.96). Male–male pairs were located within 1 km of each other on average, 0.04% of the time, whereas male–female pairs on average were 3.0%. Two male–male pairs exhibited symmetrical spatial avoidance and two symmetrical spatial attractions to the OZ. We observed simultaneous temporal attraction in three male–male pairs and four male–female pairs. Individuals from Tucson were slightly related to one another within the population (n = 13, mean R = 0.0373 ± 0.0151) whereas lions from Payson (n = 6, mean R = −0.0079 ± 0.0356) and Prescott (n = 9, mean R = −0.0242 ± 0.0452) were not as related. Overall, males were less related to other males (n = 20, mean R = −0.0495 ± 0.0161) than females were related to other females (n = 8, mean R = 0.0015 ± 0.0839). Genetic distance was positively correlated with geographic distance (r 2 = 0.22, P = 0.001). Spatial requirements and interactions influence social behavior and can play a role in determining population density.

Dispersal plays an important role in the population dynamics of many carnivores, yet little information exists about the dispersal and movement patterns of swift foxes (Vulpes velox). We radio-collared and monitored 68 swift foxes for dispersal at 2 study sites in northwestern Texas from January 2002 to April 2004. Dispersal distance for juve- niles (13.1 ± 0.3 km, s), adults (10 ± 4.7 km) and transients (25.4 ± 9.1 km) did not differ by age class (F = 1.49, df = 2, P = 0.24) or sex (F = 0.23, df = 1, P = 0.63) but differed by study site (F = 4.72, df = 1, P = 0.04). Mean dispersal dis- tance from private ranches (PR) was greater than from National Grasslands (NG). Peak dispersal occurred during Octo- ber-November (13 individuals) and January-February (7 individuals). Dispersal direction was influenced by land-use practices (i.e., toward rangelands and away from anthropogenic features). Direction of dispersal among foxes that occu- pied the NG was uniform (n = 16, P = 0.08), whereas foxes from PR dispersed in a northwesterly direction (n = 18, P ≤ 0.001) away from a town and croplands. Three resident adult foxes made extraterritorial movements. Distances of these movements ranged from 0.2 km to 11.4 km. Distance of extraterritorial movements did not differ by sex (F = 0.05, P = 0.83), nor by duration of movement (F = 1.11, P = 0.32). Knowledge of movement distances and patterns is important for conservation and protection of swift foxes and their habitats.

Biologists have suggested that prairie dog (Cynomys ludovicianus) towns provide important habitat for several prairie species including swift foxes (Vulpes velox). To examine this issue for swift foxes, we radiocollared and monitored 72 swift foxes in areas occupied by prairie dogs on the Rita Blanca National Grasslands and on fragmented private ranches in northwest Texas from January 2002 to April 2004. We overlaid swift fox locations on vegetation maps and found that swift foxes used prairie dogs towns proportionately less than expected (P < 0.001) in 5 of 6 comparisons based upon availability at both study sites. In one comparison swift foxes used prairie dog towns as expected. We also mapped swift fox den locations and found that den sites were located in prairie dog towns (2 of 106 den sites on national grasslands and 2 of 87 on private ranch for all years pooled) as expected based upon availability (P = 0.54 and P = 0.34). Previous research in these areas of Texas indicated that prairie dogs were a minor component of swift fox diet (

Throughout the range of swift fox (Vulpes velox), coyotes (Canis latrans) are the primary source of swift fox mortality. Coyotes may suppress swift fox populations where densities are high. Because coyote numbers have increased since wolves (Canis lupus) have been exterminated, we hypothesized that escape habitats may limit swift foxes. To test our hypothesis, we installed artificial escape dens in 3 spatially separated (treated) areas on the Rita Blanca National Grasslands in Dallam County, Texas, USA. From January 2002 to August 2004, we captured, radiocollared, and monitored 55 swift foxes. Annual swift fox survival in artificial escape-den–treated areas (Ŝ = 0.81) was higher than in untreated areas (Ŝ = 0.52, P = 0.07). Relative swift fox abundance was higher in treated than untreated areas in 2002 (Yates' χ2 = 4.61, P = 0.03) and in 2003 (Yates' χ2 = 4.70, P = 0.03) but not in 2004 (Yates' χ2 = 2.67, P = 0.10). However, recruitment rates were no different between treated and untreated areas ...

To determine whether swift foxes (Vulpes velox) could facilitate transmission of Yersinia pestis to uninfected black-tailed prairie dog (Cynomys ludovicianus) colonies by acquiring infected fleas, ectoparasite and serologic samples were collected from swift foxes living adjacent to prairie dog towns during a 2004 plague epizootic in northwestern Texas, USA. A previous study (1999-2001) indicated that these swift foxes were infested almost exclusively with the flea Pulex irritans. Black-tailed prairie dogs examined from the study area harbored only Pulex simulans and Oropsylla hirsuta. Although P. irritans was most common, P. simulans and O. hirsuta were collected from six swift foxes and a single coyote (Canis latrans) following the plague epizootic. Thus, both of these canids could act as transport hosts (at least temporarily) of prairie dog fleas following the loss of their normal hosts during a plague die-off. All six adult swift foxes tested positive for antibodies to Y. pestis. All 107 fleas from swift foxes tested negative for Y. pestis by mouse inoculation. Although swift foxes could potentially carry Y. pestis to un-infected prairie dog colonies, we believe they play only a minor role in plague epidemiology, considering that they harbored just a few uninfected prairie dog fleas (P. simulans and O. hirsuta).

Swift foxes (Vulpes velox) are one of the smallest and most den-dependent and nocturnal canids in North America (Egoscue 1979, Tannerfeldt et al. 2003)Though research concerning swift fox fecundity has been conducted, it is a difficult and arduous task because pups do not emerge from natal dens until they are weaned at 5-7 weeks of age (Egoscue 1979). Previous techniques for determining fecundity of swift foxes have included excavating the den and counting pre-emergent pups (Cutter 1958, Kilgore 1969) and visual counts of post-emergent pups (Covell 1992, Olson and Lindzey 2002, Schauster et al. 2002, Harrison 2003, Sovada et al. 2003). Visual counts are the most commonly reported technique for counting post-emergent swift fox pups (Covell 1992, Olson and Lindzey 2002, Schauster et al. 2002, Harrison 2003, Sovada et al. 2003). In this technique >1 concealed observers with binoculars or spotting scopes watch a female's den from a distance (usually >40 m) in the evening and morning hours during early summer, in an attempt to count the number of pups. Visual counts also have been effectively used with similar species such as the kit fox (Vulpes macrotis; Cypher et al. 2000, Koopman et al. 2000) and arctic fox (V.lagopus; Strand et al. 2000). Prior research concerning determination of preemergent pups has been highly invasive, as dens were excavated or disturbed via observer presence. As more advanced technology becomes available to researchers, less insidious means of obtaining data can be implemented. Recently, video probe systems have been used to document various cavity-nesting and burrowing animals such as red-cockaded woodpeckers (Picoides borealis; Richardson et al. 1999) and western burrowing owls (Athene cunicularia hypugea; Gervais et al. 2000). Night-vision devices have been used to enumerate migrating owls (Tyto alba,Aegolius acadicus,Asio otus, Asio flammeus, and Otus asio; Russell et al. 1991) and to observe the emergence of big brown bats (Eptesicus fuscus) from maternal colonies (Kirkwood and Cartwright 1993). Automated videography has been used to observe nests and index population abundance (York 1991, Kristan et al. 1996, Booms and Fuller 2003). Yet, none of this technology has been evaluated for use in swift fox research. Measuring fecundity is an essential component in examining demographics of any wildlife species. Information on litter sizes is necessary to understand the dynamics of swift fox populations. Yet, no pups were observed from preliminary efforts at visual counts of swift fox pups during our study. Thus, the objective of this study was to compare visual counts, night vision, a den-probe system, and an automated video monitoring system for counting swift fox pups.

Our understanding of ectoparasite ecology in wild felid populations is limited in free-ranging species and in regions such as Arizona. As part of a larger study, we collected ectoparasites from 4 radio-collared mountain lions (Puma concolor) in Tucson, Arizona (32.189N -110.881E) between January 2006 and December 2007. Ectoparasites were identified as Pulex, a genus of flea not commonly reported on mountain lions. The tick was a nymph of Argas (Alveonasus) cooleyi, a species about which little is known.

Throughout history, the science of wildlife biology and the profession of wildlife management have been dominated by men. In the early part of the 20th century there were few women wildlife biologists and they were typically junior collaborators or assistants. We quantified the evolving roles women have in The Wildlife Society (TWS) by documenting their contributions to the Journal of Wildlife Management (JWM), the Wildlife Society Bulletin (WSB), and Wildlife Monographs (WM) from the origin of TWS (the international professional society for wildlife biologists) in 1937 through 2006. Data were collected from peer-reviewed publications, participation in TWS (i.e., membership, meeting attendees, committee members, and officers), journal editors, awards, and honorary membership. While women played a minor role in TWS in 1937, their contributions have steadily increased through the years. However, publications by women have not represented their membership in TWS. Only 18% of 11,363 TWS journal articles from 1937-2006 have female contributors. In 1937, 1 of 12 JWM articles had a female author. By 2006 that contribution increased to 45%. It was not until the early 1980s that contributions by females accelerated. In 1944 2% of TWS members were women; by 2006 22% were women. Out of 488 TWS awards since 1937, 5% have been presented to women. One female was president of the society, but none has served as editor-in-chief. Three women have received an honorary membership, and 2 of the 54 recipients of the Aldo Leopold Award, the most prestigious award given by TWS, have been women. Because 22% of TWS memberships were women in 2006 they need to be encouraged to accept leadership roles in TWS. With changing demographics and 50-75% of natural resource professionals retiring by 2015, women will have important new opportunities to shape the direction and progress of wildlife management.

The relationships among locations of body fats have not been thoroughly examined in White-tailed Deer (Odocoileus virginianus). We measured bone marrow fat (n = 2995), back fat (n = 1018), kidney fat (n = 2076), and xiphoid fat (n = 1246) levels of White-tailed Deer kills from Cook and Lake counties in northeastern Minnesota during 1974-1990. For each dead deer we determined age, sex, date, and causes of mortality. All of the fat measures were correlated to varying degrees. Generally all fat measurements peaked in late autumn and subsequently began declining and reached their lowest levels in May. Fat content was negatively correlated with winter severity. Causes of mortality included predation, poaching, accidental, unknown, and auto-collisions. Predated animals had lower bone marrow (-7.42 ± 3.92) and 0.165 ± 2.30 times lower back fat and had higher amounts of kidney fat than those killed by vehicles (0.86 ± 0.43).

Predator avoidance may be a reason why Swift Foxes (Vulpes velox) are one of the most burrow-dependent canids in North America. Typically Swift Foxes have multiple dens, which they frequently move among. As part of a larger study to reduce Coyote (Canis latrans) related mortalities on Swift Foxes, we installed artificial escape dens in areas occupied by Swift Foxes on Rita Blanca National Grassland, Dallam County, Texas. For this paper, our objective was to determine the effects of artificial escape dens on Swift Fox den use patterns. From January 2002 to August 2004 we captured, radio-collared, and monitored 55 Swift Foxes. We documented annual number of dens used, rate of den use (fidelity), distance between dens, den area, and den sharing. We compared treated (artificial dens installed) and untreated (no artificial dens) areas but found no differences in annual number of dens (P = 0.64; mean = 8), rate of den use (P = 0.96; mean = 35%), mean distance between dens (P = 0.99; mean = 2,311 m), den area (P = 0.55; mean = 5.72 km2), or den sharing (P = 0.46; mean = 42% of time). We did not observe an effect of artificial escape dens on Swift Fox den use patterns probably because artificial escape dens were designed for temporary escape cover rather than diurnal den use.

Swift Fox (Vulpes velox) dens are typically found in areas were the vegetation is sparse, in loam soils, and with unobstructed views of the surrounding area. In 2002 a Swift Fox in northwest Texas was found in a unique den situated at the base of a hill with the entrance within 1 m of an active railroad track. Use of a den in such proximity to railroad tracks has never been previously reported.