For 90 years, the American Society of Mammalogists (ASM) has made science-based challenges to widespread lethal control of native mammals, particularly by the United States federal government targeting carnivores in the western states. A consensus is emerging among ecologists that extirpated, depleted, and destabilized populations of large predators are negatively affecting the biodiversity and resilience of ecosystems. This Special Feature developed from a thematic session on predator control at ASM's 2013 annual meeting, and in it we present data and arguments from the perspectives of ecology, wildlife biology and management, social science, ethics, and law and policy showing that nonlethal methods of preventing depredation of livestock by large carnivores may be more effective, more defensible on ecological, legal, and wildlife-policy grounds, and more tolerated by society than lethal methods, and that total mortality rates for a large carnivore may be driven higher than previously assumed by human causes that are often underestimated.

Predator control policies in the United States shifted in the latter half of the 20th century, largely in response to public outcry. However, few studies have assessed attitudes toward predator control at the national level. We replicated measures from a 1995 study that assessed attitudes toward predator management in the United States. We sought to determine if public support for predator management and perceptions of the humaneness of specific management practices changed over the past 2 decades. A web-based questionnaire was used to survey a representative sample of United States residents. The survey instrument contained items designed to assess attitudes toward predator management in general and the humaneness of specific predator management practices (lethal and nonlethal). We found relatively minor shifts in attitudes toward predator management, but many of the management practices assessed were rated significantly less humane than in the previous survey. Respondents were generally supportive of predator management aimed at losses of agricultural or private property; however, nonlethal methods were perceived to be far more humane than lethal methods. Our findings suggest that the public is generally supportive of predator control, but increasingly skeptical of the methods employed in control actions.

Starting in the 1970s, many populations of large-bodied mammalian carnivores began to recover from centuries of human-caused eradication and habitat destruction. The recovery of several such populations has since slowed or reversed due to mortality caused by humans. Illegal killing (poaching) is a primary cause of death in many carnivore populations. Law enforcement agencies face difficulties in preventing poaching and scientists face challenges in measuring it. Both challenges are exacerbated when evidence is concealed or ignored. We present data on deaths of 937 Wisconsin gray wolves (Canis lupus) from October 1979 to April 2012 during a period in which wolves were recolonizing historic range mainly under federal government protection. We found and partially remedied sampling and measurement biases in the source data by reexamining necropsy reports and reconstructing the numbers and causes of some wolf deaths that were never reported. From 431 deaths and disappearances of radiocollared wolves aged > 7.5 months, we estimated human causes accounted for two-thirds of reported and reconstructed deaths, including poaching in 39–45%, vehicle collisions in 13%, legal killing by state agents in 6%, and nonhuman causes in 36–42%. Our estimate of poaching remained an underestimate because of persistent sources of uncertainty and systematic underreporting. Unreported deaths accounted for over two-thirds of all mortality annually among wolves > 7.5 months old. One-half of all poached wolves went unreported, or > 80% of poached wolves not being monitored by radiotelemetry went unreported. The annual mortality rate averaged 18% ± 10% for monitored wolves but 47% ± 19% for unmonitored wolves. That difference appeared to be due largely to radiocollaring being concentrated in the core areas of wolf range, as well as higher rates of human-caused mortality in the periphery of wolf range. We detected an average 4% decline in wolf population growth in the last 5 years of the study. Because our estimates of poaching risk and overall mortality rate exceeded official estimates after 2012, we present all data for transparency and replication. More recent additions of public hunting quotas after 2012 appear unsustainable without effective curtailment of poaching. Effective antipoaching enforcement will require more accurate estimates of poaching rate, location, and timing than currently available. Independent scientific review of methods and data will improve antipoaching policies for large carnivore conservation, especially for controversial species facing high levels of human-induced mortality.

Worldwide, native predators are killed to protect livestock, an action that can undermine wildlife conservation efforts and create conflicts among stakeholders. An ongoing example is occurring in the western United States, where wolves (Canis lupus) were eradicated by the 1930s but are again present in parts of their historic range. While livestock losses to wolves represent a small fraction of overall livestock mortality, the response to these depredations has resulted in widespread conflicts including significant efforts at lethal wolf control to reduce impacts on livestock producers, especially those with large-scale grazing operations on public lands. A variety of nonlethal methods have proven effective in reducing livestock losses to wolves in small-scale operations but in large-scale, open-range grazing operations, nonlethal management strategies are often presumed ineffective or infeasible. To demonstrate that nonlethal techniques can be effective at large scales, we report a 7-year case study where we strategically applied nonlethal predator deterrents and animal husbandry techniques on an adaptive basis (i.e., based on terrain, proximity to den or rendezvous sites, avoiding overexposure to techniques such as certain lights or sound devices that could result in wolves losing their fear of that device, etc.) to protect sheep (Ovis aries) and wolves on public grazing lands in Idaho. We collected data on sheep depredation mortalities in the protected demonstration study area and compared these data to an adjacent wolf-occupied area where sheep were grazed without the added nonlethal protection measures. Over the 7-year period, sheep depredation losses to wolves were 3.5 times higher in the Nonprotected Area (NPA) than in the Protected Area (PA). Furthermore, no wolves were lethally controlled within the PA and sheep depredation losses to wolves were just 0.02% of the total number of sheep present, the lowest loss rate among sheep-grazing areas in wolf range statewide, whereas wolves were lethally controlled in the NPA. Our demonstration project provides evidence that proactive use of a variety of nonlethal techniques applied conditionally can help reduce depredation on large open-range operations.

Large predators are declining worldwide primarily due to hunting and persecution by humans, driven in large part by the livestock industry. Some ranchers are transitioning to “predator-friendly” farming by adopting nonlethal predator deterrents. On very large rangeland properties, such as the vast stations of the Australian arid zone, ending lethal control may in itself reduce livestock losses by enabling the predator's social structure to stabilize. The dingo (Canis dingo), Australia's apex predator, is commonly subjected to eradication campaigns to protect livestock. We analyzed causes of cattle (Bos taurus) deaths on Evelyn Downs, a 2,300-km² predator-friendly station in central Australia, for 2 years after dingo protection was established. Husbandry-related challenges, associated with deteriorating environmental conditions, were the leading causes of deaths of cattle. Predation by dingoes was minor and declined as the indices of dingo abundance stabilized and social stability increased. Shifting from killing predators to improving husbandry standards is likely to improve livestock survival and welfare.

Details surrounding any particular instance of predator control are varied. Addressing the appropriateness of predator control requires attention to those details. Here, we focus on the case of wolf (Canis lupus) hunting in Michigan. In Michigan, wolves were removed from the list of United States endangered species in December 2011. By June 2013, plans had been finalized to begin hunting wolves in fall 2013. According to these plans, a purpose of the hunt was to reduce wolf abundance in particular regions of Michigan to reduce threats to livestock and human safety. Here, we evaluate those plans using 2 basic tenets of wildlife management. The 1st tenet is the North American Model of Wildlife Conservation, which is held in high regard by many hunting organizations, wildlife professionals, and state agencies. A central component of the North American Model of Wildlife Conservation is a set of 7 principles representing ideas such as that wildlife is held in the public trust, management should be based on principles of democracy and best-available science, and wildlife should only be killed for a legitimate purpose. The 2nd tenet pertains to the ability to answer 3 fundamental questions: What is the purpose or goal of a management action? How will the management action meet the purpose or goal of the actions? Why are the purpose and goals appropriate? Plans for hunting wolves in Michigan appear not to meet the principles of either tenet. This conclusion suggests that either wolf hunting as it has been planned in Michigan is inappropriate or both sets of standards for evaluating wildlife management are inappropriate. Better understanding of issues like this will require reflecting on the fundamental nature of wildlife management and its guiding principles.

Predation by large carnivores is a dominant factor shaping wildlife communities and an understanding of local foraging strategies of predators is central to the management of wildlife populations. Information on local foraging strategies is particularly important where carnivores might exploit alternate resources that could influence predator–prey interactions, carnivore population dynamics, and a variety of interactions at lower trophic levels. We used carbon (δ¹³C) and nitrogen (δ¹⁵N) values in serially sampled wolf (Canis lupus) vibrissae to quantify relative resource use and dietary variation among wolves (n = 115) from 4 areas in southwestern Alaska that differed in the availability of terrestrial and marine resources. Mean vibrissae isotope values varied by ∼8‰ for δ¹³C and ∼12‰ for δ¹⁵N and showed high levels of spatial, seasonal, and individual variation. While results showed that ungulates were the principal prey for wolves in all 4 areas, wolves also exploited a variety of alternate marine resources that represented an important component of wolf diets in some areas. Estimated dietary contributions from marine resources ranged from 28% to 56% among areas and use of these resources varied both spatially and seasonally. Dietary variation and use of marine resources increased from northeast to southwest along the Alaska Peninsula with increasing access to coastal areas and decreasing ungulate abundance. Seasonal shifts in resource use were also evident with dietary variation being highest during summer and fall when wolves consumed more alternate resources than during winter. Our findings suggest that use of marine resources and local variation in foraging strategies of wolves might, through a variety of pathways, have broad implications for the management of wolf–ungulate communities in southwestern Alaska.

Larger predators can affect smaller predators through intraguild predation and competition, which in turn could have indirect effects on other consumers. We investigated whether gray wolves (Canis lupus) generate such effects by reducing predation by coyotes (Canis latrans) on snowshoe hares (Lepus americanus). We also examined whether wolves indirectly affect abundances of deer mice (Peromyscus spp.) as part of a wolf–coyote–fox cascade. We compared habitat use by consumers in the high- and low-wolf-use areas of a Great Lakes forest (Wisconsin and Michigan, United States). Coyotes frequented high-wolf-use areas about half as much low-wolf-use areas, which coincided with a tripling of hare browse on saplings in high-wolf-use areas. Foxes (Vulpes vulpes and Urocyon cinereoargenteus) frequented high-wolf-use areas almost exclusively. Fewer mice occurred in high-wolf-use areas than low-wolf-use areas in 2011 (approximately one-half) and 2013 (approximately two-fifths), but not in 2012, possibly due to increased food supply. We conclude that wolves may generate cascading effects through changes in coyote distribution that benefit hares and foxes, while also reducing the deer mouse population in some years.

Both historical and contemporary factors may influence the structure and composition of biotas. Small mammal faunas in the Sierra Nevada of California, United States, are strongly dominated by generalist species; however, whereas 1 recent study argues that this is a product of recent anthropogenic influences, another provides a deeper evolutionary explanation based on historic fire frequencies. We summarize these patterns and proposed mechanisms, and we integrate data from 2 other studies—1 in the Sierra Nevada and 1 from an evolutionarily related mountain range in Baja California—to provisionally conclude that evolutionary adaptation, and possibly climatic warming in the Holocene, likely are the primary drivers of this faunal structure. However, we agree with work elsewhere in North America that recent anthropogenic filtering likely has amplified the effects of adaptation and climatic warming; one result of this is that the Sierra Nevada currently supports very limited areas of older (decadent) forests, and species dependent on these habitats may require special attention by resource managers.

Sexual segregation occurs frequently in sexually dimorphic species, and it may be influenced by differential habitat requirements between sexes or by social or evolutionary mechanisms that maintain separation of sexes regardless of habitat selection. Understanding the degree of sex-specific habitat specialization is important for management of wildlife populations and the design of monitoring and research programs. Using mid-summer aerial survey data for Dall's sheep (Ovis dalli dalli) in southern Alaska during 1983–2011, we assessed differences in summer habitat selection by sex and reproductive status at the landscape scale in Wrangell-St. Elias National Park and Preserve (WRST). Males and females were highly segregated socially, as were females with and without young. Resource selection function (RSF) models containing rugged terrain, intermediate values of the normalized difference vegetation index (NDVI), and open landcover types best explained resource selection by each sex, female reproductive classes, and all sheep combined. For male and all female models, most coefficients were similar, suggesting little difference in summer habitat selection between sexes at the landscape scale. A combined RSF model therefore may be used to predict the relative probability of resource selection by Dall's sheep in WRST regardless of sex or reproductive status.

Olfactory communication among mammals remains poorly studied yet may be key to understanding their ecology. This is particularly true for mammalian carnivores, which rely extensively on scent marking for communication. Previous research suggests that carnivore latrines play a large role in both intra- and interspecific communication. Despite the apparent complexity of mammal use of latrines, little work has examined behavior patterns of species that visit latrines. We used motion-triggered video cameras to study use and behavior of mammals at ocelot (Leopardus pardalis) latrines in Costa Rica. We documented temporal patterns of use by the focal species (ocelots), diversity of mammalian species using latrines, and behaviors that occurred at these sites. Ocelots showed peaks in visitation every 60–67 days and a shorter gap between intersexual versus intrasexual visits, supporting the idea that ocelot latrines are used to communicate information about reproductive status. Fourteen terrestrial mammal species visited the latrines, and these species engaged in a variety of behaviors, including mark investigation, scent marking, and acceptance of scent marks. The complexity and frequency of behaviors by nonfocal species suggest that latrines may play as important a role in communication for these other species as they do for ocelots.

The lowland tapir (Tapirus terrestris, Linnaeus 1758) is one of the surviving members of the Neotropical megafauna. In Brazil, lowland tapirs are considered vulnerable according to the IUCN Red List of Threatened Species and endangered within the Atlantic Rain Forest biome. We aimed to provide the 1st estimates of density and population size for T. terrestris for Vale Natural Reserve (VNR). We predicted the relationships of 6 covariates to habitat occupancy. Density was estimated by the use of distance-sampling techniques, while occupancy, detectability, and activity patterns were assessed with camera-trap monitoring at 39 sample sites over a 1-year period. Density for T. terrestris was 0.8±0.2 lowland tapirs/km² and population size was 200±33 individuals. Occupancy probability was described by 2 covariates (density of palm trees and distance to water resources) and detectability by those same 2 covariates plus 2 more (distance to road and density of poaching). The species showed the 3 highest peaks of activity at 1900, 2300, and 0400 h. We concluded that VNR still harbors a viable population of lowland tapirs. However, anthropic impacts in the reserve such as poaching and road kills could already be directly affecting the lowland tapir population and producing indirect effects for the whole ecosystem. Results presented herein can be a starting point to support future work in the region and to make predictions regarding the ecosystem relationships, management, and conservation of lowland tapirs.

Seed predation and rodent foraging behaviors depend on frequency of available seeds and seed traits. However, the interaction of frequency of seed availability and seed traits adds a new level of complexity to granivore–seed dynamics. We conducted experiments with eastern gray squirrels (Sciurus carolinensis) designed to elucidate the frequency × trait interaction. We hypothesized that frequency-dependent caching should occur only among pairs of seeds that are relatively similar in attributes that affect their perceived value as a storable food item. We also tested whether caching decisions were dependent on seeds already cached, a variable rarely considered in seed dispersal studies. Frequency-dependent seed caching occurred when seeds of relatively similar value (Juglans regia and Castanea mollissima) were paired. For this seed pair, caching decisions by S. carolinensis were dependent on seeds already cached such that squirrels tended to cache seeds that were either rare in the environment or in the cache. When seeds of very different caching values were paired (Juglans nigra and Corylus americana), a strong preference for the high-value seed was observed, but no frequency-dependent selection. We conclude that in pairings of seeds of differential caching value, the highly preferred seed is cached regardless of frequency of availability. In contrast, when seeds of similar value are paired, rarer (more common) seeds are cached at a higher (lower) rate than expected, and this behavior potentially stabilizes seed survival across available seed types leading to increased tree diversity. Our results indicate that caching of seeds by squirrels, and by implication recruitment of seedlings into plant populations, is likely driven by complex interactions between the relative frequency of seeds and their traits. We expect similar patterns to occur in any system in which foragers select among resource types that vary in perceived value.

Due to successful conservation efforts, several marine mammal populations have increased in the past 40 years, leading to the possibility of increased competition for resources. We evaluated competition for haul-out space in western Atlantic harbor seals (Phoca vitulina concolor) by assessing agonistic interactions at 2 haul-out sites in Casco Bay, Maine. We predicted that intensity and rate of interactions increase as density increases, larger seals win more interactions than smaller seals do, seals already occupying a space win more interactions than arriving seals, and intensity of interactions is higher during molt but rates are higher during post molt. During molt at Gunpoint Ledge, 1 of the 2 sites, intensity of interactions decreased as density increased, but the pattern reversed during post molt. Rate of interactions peaked at intermediate density. Size and age class did not affect outcomes of interactions, but seals that already occupied space won more interactions than expected by chance. Interaction rate was higher during molt versus post-molt seasons. Harbor seals may experience increased competition for limited haul-out space as populations continue to grow, with seals occupying space outcompeting intruders.

The Caspian seal, Pusa caspica, is an ice-breeding phocid endemic to the Caspian Sea. The breeding behavior of this species is poorly documented. Here, we report behavioral observations of 518 mother–pup pairs (MPs) and 210 lone pups (LPs), made from the bridge of icebreakers traversing seal breeding grounds while servicing oil installations in the northeastern Caspian Sea, during 34 trips from late January to early March, 2006–2012. The breeding habitat of Caspian seals is land-fast or drift ice, usually at least 20 cm thick, overlying water 3–5 m deep. Pregnant females formed pairs or small groups. They were not observed to use lairs, but preferentially pupped beside ice ridges or ice-slab piles that afforded shelter to pups. In years when there were few natural leads into the ice-field, females often gave birth on the edge of artificial leads formed by shipping channels. Pups were categorized into stages from 1) newborn, 2) white-coat, 3) molting, and 4) molted, with stage 3 and 4 pups appearing from mid- to late February. The nursing period lasted at least 3 weeks and neighboring MPs appeared to be mutually tolerant. Mothers left their pups alone or at nursery sites, presumably to forage. Most white-coat pups moved over the ice while avoiding water in response to disturbance from vessels. MPs maintained contact while moving across the ice by a combination of the pup's following response and diligent chaperoning by the mother. During disturbances, some LPs sought refuge in shelters under ice slabs, whereas others followed a neighboring MP away from the vessel. Male–female pairing occurred in late season with no male–male competition observed on the ice. While breeding and pup-rearing behavior of Caspian seals has some features in common with that of other Holarctic seals, it is largely distinct and adapted to the unique conditions of the Caspian environment, in particular the paucity of snow cover on the ice.

Specimens of the Peromyscus boylii species group occurring in the montane regions of Michoacán, México, historically have been assigned to P. levipes. However, previous studies have shown that some specimens from eastern Michoacán possessed mitochondrial DNA haplotypes and karyotypes that were distinct from P. levipes and other members of the P. boylii species group. Phylogenetic analyses (parsimony and likelihood) of additional DNA sequences obtained from the mitochondrial cytochrome-b gene indicated that specimens from central and eastern Michoacán and western Morelos formed a monophyletic clade that was sister to a clade containing representatives of P. beatae. Estimations of genetic divergence for members of these 2 sister clades exceeded 5% and were greater than most pairwise comparisons reported for other members of the P. boylii species group. Collectively, there are no discernable morphological differences between those specimens and other cryptic species in the P. boylii species group. Together, these results indicated that specimens from the Sierra Madre del Sur region of Michoacán, Morelos, and likely throughout the Neovolcanic Axis of the Estado de México represent an undescribed species of Peromyscus for which we propose the name Peromyscus kilpatricki.

China has 26 species in the tribe Arvicolini. The taxonomic status of these voles remains controversial despite much effort. Herein, we evaluate the taxonomic position of 22 species plus 2 unidentified taxa using mitochondrial DNA gene sequences (cytb + CO1). We also evaluate 18 species and 2 unidentified taxa using morphological data. Phylogenetic analyses of cytb resolve monophyly for the genera Alexandromys, Lasiopodomys, Microtus,Neodon, Proedromys, and Volemys with strong support. Stenocranius clusters with Chionomys but with very weak support. Analyses of concatenated cytb + CO1 resolve the same genera with strong support, but the topology of the tree differs from that of cytb in that Chionomys roots at the base of the tree independent of Stenocranius, which forms the sister-group of Lasiopodomys in a more terminal position. The matrilineal genealogy excludes the type species Arvicola amphibius from the rest of the Arvicolini. This species forms the sister-group of Ondatra with high support. Neodon includes N. irene, N. linzhiensis, N. fuscus, N. leucurus, N. sikimensis, Microtus clarkei, and 2 unidentified specimens. Alexandromys includes the former species Microtus oeconomus, M. kikuchii,M. limnophilus, M. fortis, and M. maximowiczii. Finally, Microtus has the subgenera Blanfordimys, Microtus,Mynomes, Pedomys, Pitymys, and Terricola, which includes the Chinese species M. agrestis, M. arvalis, and Blanfordimys juldaschi. General mixed Yule-coalescent species delimitation modeling demarcates 6 currently recognized species and 2 new species of Neodon. A principal component analysis of the morphological data among 7 matrilines shows that all variables have positive loadings of high magnitude on the 1st component. Canonical discriminant analysis for Neodon (including M. clarkei and 2 unidentified species) correctly classifies 93.0% of specimens. Overall, our analyses support the recognition of Alexandromys, Lasiopodomys, Microtus,Neodon, Proedromys, and Volemys as genera. Stenocranius includes Microtus gregalis, and the genealogical position of Stenocranius remains uncertain. The status of Arvicola requires further study. We assign M. clarkei to Neodon and describe 2 new species of Neodon.

Version of Record, first published online November 16, 2016, with fixed content and layout in compliance with Art. 8.1.3.2 ICZN.

Many African mole-rats (Bathyergidae) exhibit distinct circadian rhythms, despite the fact that they are strictly subterranean and are very infrequently exposed to light. We investigated the circadian system of Emin's mole-rats (Heliophobius emini) by exposing 13 individuals to different lighting regimes. The mole-rats were subjected to a standard 12-h light: 12-h dark light cycle, followed by a constant darkness (DD) cycle to evaluate entrainment and endogenous rhythms of locomotor activity. After allowing the mole-rats to re-entrain to a 12L:12D light cycle, the light cycle was inverted to examine the duration of re-entrainment following a drastic change in the light cycle. Furthermore, we investigated the effect of different ambient temperatures on the locomotor activity of the mole-rats, and they were thus subjected to a 12D:12L light cycle at 20°C, 25°C, and 30°C. Lastly, molerats were presented with a long-day (16L:8D) and a short-day (8L:16D) light cycle to look at the effect on preferred active time. The animals showed a preference for diurnal activity with 9 mole-rats entraining to the light cycle, and maintaining clear endogenous rhythms throughout DD. Subjects were excessively slow to reentrain their activity to the inverted light cycle. When subjected to different ambient temperatures, individuals showed marked increases in average activity at 20°C, with the lowest average activity occurring at 30°C. The mole-rats maintained their diurnal preference regardless of day length, condensing their activity during the shortday light cycle, while extending their active period during the long-day cycle. These results suggest that Emin's mole-rats are able to perceive light and entrain their locomotor activity to light cycles, albeit weakly. In addition, ambient temperature influenced the level of overall activity, indicating that these animals may use behavioral thermoregulation to maintain a constant body temperature.

Female-biased sexual dimorphism is uncommon in mammals and is usually attributed to increased fecundity of large females. Moreover, sexual dimorphism is usually described for adults, and the ontogeny of sex differences is poorly documented. We studied cliff chipmunks (Tamias dorsalis), a small mammal with female-biased sexual dimorphism, to describe development of sexual dimorphism in juveniles and to measure sexual dimorphism and seasonal body mass in adults. To test the fecundity hypothesis, we compared body mass of females to litter size and body mass of offspring. Juveniles were not sexually dimorphic at emergence from the nest and did not differ in body mass 2 months after emergence. Adult chipmunks maintained a relatively stable body mass in March– October with females consistently larger than males. Maternal mass did not have an effect on litter size or mass of juveniles. Because females were consistently larger than males, the ontogeny of sexual dimorphism may provide insights into selection pressures that lead to female-biased sexual dimorphism.

A substantial body of work exists describing timing of migration and hibernation among bats in eastern North America, but less is known about these events among bats inhabiting the Rocky Mountain region. Yellowstone National Park is a geothermally influenced landscape comprised of diverse habitats, creating the opportunity for unique behaviors to develop among local bat populations. We identified the timing of migration for the local bat community and determined if bats overwinter in Yellowstone. To accomplish this, we radiotracked 7 little brown myotis (Myotis lucifugus), 5 western long-eared myotis (M. evotis), 4 big brown bats (Eptesicus fuscus), 4 silver-haired bats (Lasionycteris noctivagans), and 1 western small-footed myotis (M. ciliolabrum) from August to September 2010 and September to October 2011. We also used acoustic detectors to record bat activity from November through April 2011–2014 and sampled abundance of nocturnal insects using black-light traps from 2011 to 2012. Although availability of insects declined rapidly during August and afterward, several bat species remained active throughout autumn and winter. Bat activity was recorded during all months, even during periods of extreme cold. Radiotagged big brown bats, little brown myotis, and western small-footed myotis remained active in the study area throughout October, after the 1st snowfall of the season. While data for activity patterns in late autumn and winter prevented an estimation of the onset of hibernation, spring emergence occurred in April despite persistence of winter conditions. These data provide insights into the migration and hibernation strategies of bat populations in the Rocky Mountains and highlight gaps in our understanding of seasonal changes in these species.

Characterizing habitat use is a key component to quantifying the niche, ecological interactions, and conservation needs of a species. Habitat selection is the disproportionate use of habitat types, whereby animals select higher-quality habitats within a landscape mosaic. For insectivorous bats, selection of foraging habitat is likely due to variation between habitat types in the distribution and abundance of prey, as well as differences in how effectively bats can move through, and forage in, different landscapes. Due to their cryptic nature and rapid nocturnal flight, detailed knowledge about fine-scale habitat selection of bat species is lacking. We used data-logging telemetry receivers to assess selection of foraging habitat by the little brown bat, Myotis lucifugus, in the Badlands and Missouri River Valley of North Dakota. Bats were captured at maternity roosts, fitted with radiotransmitters, and tracked for 11 nights at each site. Habitat selection was assessed based on selection ratios of used and available proportions of habitat, which were characterized in terms of both composition and structure. Eigenanalysis of selection ratios was used to further evaluate individual variation in habitat selection. Foraging female M. lucifugus primarily selected edge habitats and nearby water sources. Pregnant bats selected edges bordering grass or herbaceous habitats. Lactating bats selected water and edge habitat within close proximity to the roost. Selection of nearby water resources by lactating bats under the constraints of nursing is consistent with previous studies. While there were ecologically consistent trends across bats, individuals varied in some aspects of their habitat selection.

Spatial behavior and habitat use of breeding mammalian females often change after parturition, reflecting not only the sharp increase in energy demands associated with lactation, but sometimes also limitations of a central place, if they return regularly to feed their altricial young. We conducted the 1st radiotracking study of habitat preferences of the pond bat (Myotis dasycneme), a threatened habitat specialist, comparing movements of breeding females during pregnancy and lactation in a lakeland zone of Poland. Pond bats are known to forage almost exclusively over water bodies. We predicted that 1) females commute shorter distances during lactation than during pregnancy, as they need to return to the colony during night to feed their young, and 2) pond bats select eutrophic lakes due to greater abundance of aquatic insects. The 1st prediction was confirmed, as pregnant females covered significantly longer distances between roosts and foraging sites (median 11.4 km) than lactating females (median 2.9 km). During pregnancy, bats foraged mostly over lakes and only rarely over rivers, using both habitats as available, but carp fishponds were selected. Lactating females selected rivers and canals but avoided lakes. The 2nd prediction was confirmed only in spring. Pregnant females selected eutrophic and avoided mesotrophic lakes, whereas during lactation, mesotrophic lakes were selected and eutrophic ones were avoided. This could explain the switch from chironomids, of smaller body size and found in eutrophic waters, to larger caddisflies, found in fast-flowing rivers, observed the diet of pond bats in a previous study. Lactating females may maximize their energy gain by shifting to large insects, thus obtaining larger portions of energy by a single capture effort. This study exposes the importance of small, relatively fast-flowing rivers in an energetically crucial period of the year for a species that has been perceived as associated with larger water bodies.

In seasonally varying environments, animals should alter habitat selection through time to avoid the harshest conditions. Winter severity is limiting for many ungulates in high-latitude ecosystems, and quality of habitat is an important determinant of winter survival. Previous studies in Southeast Alaska indicated that Sitka black-tailed deer (Odocoileus hemionus sitkensis) selected old-growth forest that provides both snow interception and forage, but with great variability among studies, years, and geographic areas. Clearcut timber harvest has greatly reduced the extent and quality of old-growth forest. The value of 2nd-growth and old-growth forest types to deer likely depends on snow depth, which is highly variable in space and time. We measured selection for vegetation classes, landscape features, and forage biomass by monitoring 56 GPS-radiocollared adult female deer from 1 January to 1 April between 2011 and 2013. Simultaneously, we measured snow depth across deer home ranges daily. We determined that snow depth had a strong effect on selection for vegetation classes. During periods of low snow, deer selected young 2nd growth but avoided old 2nd growth and high-volume old growth. As snow depths increased, young 2nd growth was avoided and deer selected old 2nd-growth and productive old-growth forests. The composition of vegetation classes within the landscape influenced selection, with deer selecting locally abundant habitats. These behaviors suggest that the widespread distribution of forest patches that provide snow interception and forage biomass may be critical to fulfilling the energetic requirements of deer during winters with snow. Such context-dependent habitat selection is likely widespread among wildlife species in variable environments and should be incorporated into study design and analysis.

Species that make long-distance migrations face changes in the phenology of natural processes linked to global climate changes. Mismatch between the onset of resources and arrival on breeding grounds or changes in the conditions faced during migration such as early snowmelt in northern environments could have severe impacts on migrant populations. We investigated the impact of local weather and broad-scale climate and of the availability of forage resources on timing of spring and fall migrations of migratory caribou (Rangifer tarandus) from the Rivière-George and Rivière-aux-Feuilles herds in northern Québec and Labrador, Canada. We tested the effect of local weather using data provided by the Canadian Regional Climate Model, a large-scale climate index, snow and ice cover, and the Normalized Difference Vegetation Index on departure and arrival dates of 377 spring migrations and 499 fall migrations of female caribou. Since 2000, except for the spring arrival, migrations tended to occur earlier. Spring arrival was delayed when caribou encountered mild temperatures and abundant precipitation during migration, as early snowmelt may increase cost of movements. At greater population sizes, caribou seemed to limit the time spent on summer range by arriving later and departing earlier, possibly to limit competition for summer forage. During fall, caribou adjusted their migration to conditions en route because they arrived earlier if November was snowy and mild, possibly to limit the costs of moving through deep snow. Like numerous migrant species, most caribou herds are declining, and it is crucial to assess which environmental factors affect migrant populations. Our study contributes to the understanding of the impact of local weather conditions and climate change on migratory land mammals.

Madagascar's native small mammals (Tenrecidae and Nesomyinae) are understudied. To help fill these knowledge gaps, we analyzed 1,575 detections of small mammals obtained during camera-trap surveys at 7 sites in northeastern Madagascar (2008–2011) using single-season occupancy analyses in program PRESENCE. We estimated landscape occupancy and detection probabilities of tufted-tailed rats (Eliurus spp.), red forest rats (Nesomys spp.), greater hedgehog tenrecs (Setifer setosus), and common tenrecs (Tenrec ecaudatus) and examined how these parameters responded to habitat characteristics, habitat degradation, and the trap success of native and exotic carnivorans. Only Nesomys showed a marked difference in mean occupancy between intact (Ψ = 0.71 ± SE 0.06), intermediately degraded (Ψ = 0.23 ± SE 0.05), and degraded (Ψ = 0.34 ± SE 0.06) forest sites. Only Nesomys and Setifer occupancy was strongly influenced by habitat characteristics; Nesomys occupancy was positively related to distance away from forest edge (β = 1.39 ± SE 0.27) and percent rainforest cover (β = 1.89 ± SE 0.39), and Setifer occupancy negatively related to average canopy height (β = –0.52 ± SE 0.25). We found trap success of exotic carnivorans had little influence on small mammal occupancy and detection probabilities (with the exception of Eliurus). We suggest that camera traps are a valid method for studying aspects of small mammal ecology, but caution researchers to consider characteristics of camera traps (e.g., trigger speed) to increase potential inference.

Understanding the demography of an invasive species is crucial to better guide managers seeking to slow the spread of the invader. Habitat differences can affect demographic rates, which may in turn impact the speed of the invasion, but this has been rarely addressed. We studied the demography of invasive North American beavers (Castor canadensis) in 2 contrasting habitat types of the island, forest and steppe, on Tierra del Fuego in southern Patagonia. We used repeated observations, mark-resight methods, telemetry, and camera traps to estimate colony size and demographic rates of beavers in the 2 habitats. Colony size and the number of offspring (“kits”) produced per colony per year were higher in the steppe, contrary to the belief that forest is better habitat. This may be the result of the longer time since invasion in the forests of Tierra del Fuego and that the forest subpopulation is showing density-dependent regulation. Survival of beavers was high in all age classes and was higher than survival rates recorded in North America. Our work shows that plasticity of habitat use and predator release have likely facilitated beaver invasion in Patagonia. The higher productivity and detectability of beavers in the steppe call for active management in a habitat previously assumed to be subprime.

Sierra de Coneto (SC) is a small mountain range located at the transition between the Sierra Madre Occidental (SMO) and the Mexican Plateau (MP) in which unique combinations of potential habitats for rodents occur, and where the distribution of species of the 2 regions overlap. We examined how species of small rodents at the Sierra de Coneto select macrohabitat (vegetation type) and microhabitat (measured as vegetation structure, composition, and ground cover). If rodents select at the macrohabitat level, we expect associations with vegetation type, whereas if rodents select at the microhabitat level, we expect associations with specific attributes of vegetation or substrate regardless of the vegetation type where such attributes occur. We sampled for 3 nights using two 100-Sherman trap transects along a vegetation gradient. We assessed responses of rodents to microhabitat using canonical correspondence analysis and multiple linear regression. At the macrohabitat level, we found associations of Peromyscus difficilis and Sigmodon ochrognathus with chaparral, and of P. boylii and P. pectoralis with desert scrub. At the microhabitat level, these species were associated mostly with attributes of their vegetation types. P. hooperi and Neotoma leucodon were associated only with specific microhabitat attributes. Our results indicate that the scale of habitat selection is species-dependent, and that attributes selected can be important at different scales for different reasons (e.g., oaks as cover, or oak seeds as food). Understanding how and at which scale species relate to their environment is key to predicting the effects of natural and anthropogenic modifications on natural populations.

Acoustic communication is favored at times of day and under weather conditions that allow the most effective sound transmission. Changes in vocal activity due to temporal and environmental factors can add significant information about the function of animals' calls by providing clues about behavioral patterns. Estimating the temporal variation of vocal activity also can be important for conservation when calls are used to infer a species' presence and abundance. The maned wolf (Chrysocyon brachyurus) is a near-threatened species and its conservation efforts could benefit from information gathered using passive acoustic monitoring (PAM), but their vocal behavior pattern in the wild is currently unknown. We investigated the nocturnal pattern of roar-bark sequences by maned wolves in Serra da Canastra National Park (Minas Gerais, Brazil) during 4 months of the breeding season and measured the influence of period of night, weather conditions, and lunar phase on their vocal activity. Roar-barks were more frequently emitted in the first 3 h of the night, suggesting an important social function for these long-distance calls in the beginning of the period of greatest activity of maned wolves. The occurrence of sequences was negatively related to mean wind speed, which suggests that wolves are avoiding moments of poor sound transmission. No sequence was detected when wind speed was above 5.4 m/s, probably due to equipment limitation, masking by wind noise, or absence of vocal activity. Maned wolves also vocalized more during moonlit nights. A better understanding of seasonal variation in vocal activity of maned wolves is required, but our study shows that it is possible to detect behavioral patterns of wild populations of this species only by sound, validating PAM as a tool for the conservation of this threatened carnivore.