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All existing sea otter (Enhydra lutris) populations have suffered at least 1, and in some cases 2, population bottlenecks. The 1st occurred during the 18th and 19th centuries as a result of commercial hunting that eliminated sea otters from much their native range and reduced surviving populations to small remnants. The 2nd bottleneck occurred when small numbers of otters were reintroduced, via translocation, to areas where the species had been eliminated. We examined genetic variation at 7 microsatellite loci and the mitochondrial DNA (mtDNA) control region in 3 remnant populations, Amchitka Island (Aleutian Islands, Alaska), central coastal California, and Prince William Sound (Alaska), and in 2 reintroduced populations,...
Categories: Publication; Types: Citation; Tags: Journal of Mammalogy
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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...
Categories: Publication; Types: Citation; Tags: Journal of Mammalogy
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Fire is a natural, dynamic process that is integral to maintaining ecosystem function. The reintroduction of fire (e.g., prescribed fire, managed wildfire) is a critical management tool for protecting many frequent-fire forests against stand-replacing fires while restoring an essential ecological process. Understanding the effects of fire on forests and wildlife communities is important in natural resource planning efforts. Small mammals are key components of forest food webs and essential to ecosystem function. To investigate the relationship of fire to small mammal assemblages, we live trapped small mammals in 10 burned and 10 unburned forests over 2 years in the central Sierra Nevada, California. Small mammal...
Categories: Publication; Types: Citation; Tags: Journal of Mammalogy
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This paper describes the home range defense behavior observed when nonresident male red foxes were introduced into established home ranges of resident male-female pairs. In 12 observation periods, four intruders were introduced to each of three mated pairs which had been given three weeks to acclimate to a 4.05-hectare, fenced enclosure. The residents centered their activities around a natural den and the frequency of intruder-resident encounters decreased rapidly with increasing distance from the den. The primary home range defense was continual harassment of the intruders by the resident males through agonistic displays and chases. Physical contact was rare. Even though the resident males were dominant in less...
Categories: Publication; Types: Citation; Tags: Journal of Mammalogy
The length of gestation is the number of days between fertilization and parturition, and the length of lactation is the number of days between parturition and weaning. Determination of these lengths is difficult for ground-dwelling squirrels such as prairie dogs, marmots, and ground squirrels that usually copulate, give birth, and nurse offspring underground. For Gunnison's prairie dogs (Cynomys gunnisoni), the mean +1 SD length of gestation is 29.3 ? 0.53 days (n = 124). The approximate length of lactation, estimated from the mean +1 SD duration between parturition and the first emergence of juveniles from the natal burrow, is 38.6 ? 2.08 days (n = 112). Published in Journal of Mammalogy, volume 78, issue 1, on...
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Few studies of sexual segregation in ruminants have tested widely invoked mechanisms of segregation in mixed-sex groups. In a sexually segregated population of Roosevelt elk (Cervus elaphus roosevelti), we examined if adult males had reduced intake of forage when in mixed-sex groups and if intersexual differences in aggression caused females to avoid males. Based on a mechanistic model of forage intake, animals with lower instantaneous feed intake should have higher cropping rates. Focal animal sampling indicated that adult males and females in summer and winter had similar cropping rates in mixed-sex groups, whereas males in male-only groups had lower rates of cropping than males in mixed-sex groups. Outside the...
Categories: Publication; Types: Citation; Tags: Journal of Mammalogy
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Population parameters, mortality causes, and mechanisms of a population decline were studied in wolves (Canis lupus lycaon) from 1968 to 1976 in the Superior National Forest. The main method was aerial radio-tracking of 129 wolves and their packmates. Due to a decline in white-tailed deer (Odocoileus virginianus), the wolf population decreased during most of the study. Average annual productivity varied from 1.5 to 3.3 pups per litter, and annual mortality rates from 7 to 65 percent. Malnutrition and intraspecific strife accounted equally for 58 percent of the mortality; human causes accounted for the remainder. As wolf numbers began to decline, pup starvation became apparent, followed by lower pup production, and...
Categories: Publication; Types: Citation; Tags: Journal of Mammalogy
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The wolverine (Gulo gulo) is an uncommon, wide-ranging carnivore of conservation concern. We evaluated performance of landscape models for wolverines within their historical range at 2 scales in the interior Northwest based on recent observations (n = 421) from Washington, Oregon, Idaho, and Montana. At the subbasin scale, simple overlays of habitat and road-density classes were effective in predicting observations of wolverines. At the watershed scale, we used a Bayesian belief network model to provide spatially explicit estimates of relative habitat capability. The model has 3 inputs: amount of habitat, human population density, and road density. At both scales, the best models revealed strong correspondence between...
Categories: Publication; Types: Citation; Tags: Journal of Mammalogy
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Neotropical felids such as the ocelot (Leopardus pardalis) are secretive, and it is difficult to estimate their populations using conventional methods such as radiotelemetry or sign surveys. We show that recognition of individual ocelots from camera-trapping photographs is possible, and we use camera-trapping results combined with closed population capture-recapture models to estimate density of ocelots in the Brazilian Pantanal. We estimated the area from which animals were camera trapped at 17.71 km2. A model with constant capture probability yielded an estimate of 10 independent ocelots in our study area, which translates to a density of 2.82 independent individuals for every 5 km2 (SE 1.00).
Categories: Publication; Types: Citation; Tags: Journal of Mammalogy
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We studied ontogeny of predatory skills of growing black-footed ferrets (Mustela nigripes) raised under different captive conditions. To test effects of maturation, experience, and cage enrichment on predatory behavior, we exposed 70 juvenile black-footed ferrets to different numbers of live hamsters (Mesocricetus auratus) throughout development. Both maturation and experience increased the likelihood of a black-footed ferret making a successful kill. Black-footed ferrets exposed to greater environmental complexity (enriched cage, including encouragement of food-searching behaviors) also were more likely to kill than ferrets raised in a deprived environment. Behavioral studies of captive-raised black-footed ferrets...
Categories: Publication; Types: Citation; Tags: Journal of Mammalogy
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Black-footed ferrets (Mustela nigripes) apparently were extirpated from all native habitats by 1987, and their repatriation requires a combination of captive breeding, reintroductions, and translocations among sites. Improvements in survival rates of released ferrets have resulted from experience in quasi-natural environments during their rearing. Reestablishment of a self-sustaining wild population by 1999 provided the 1st opportunity to initiate new populations by translocating wild-born individuals. Using radiotelemetry, we compared behaviors and survival of 18 translocated wild-born ferrets and 18 pen-experienced captive-born ferrets after their release into a prairie dog colony not occupied previously by ferrets....
Categories: Publication; Types: Citation; Tags: Journal of Mammalogy
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Knowledge of seasonal movements by pronghorns (Antilocapra americana) within the easternmost extension of sagebrush-steppe communities is limited. Current hypotheses regarding movement patterns suggest that pronghorns initiate seasonal movements in response to severe winter weather, snowfall patterns, spatial and temporal variation in forage abundance, and availability of water. From January 2002 to August 2005, we monitored movements of 76 adult (≥1.5 years) female pronghorns on 2 study areas (Harding and Fall River counties) in western South Dakota. We collected 8,750 visual locations, calculated 204 home ranges, and documented 17 seasonal movements. Eighty-four percent (n = 55) of pronghorns were nonmigratory...
Categories: Publication; Types: Citation; Tags: Journal of Mammalogy
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We tested the 5% rule for the ratio of radiotransmitter mass to body mass by applying radiotransmitters and passive integrated transponders (PIT tags) or PIT tags alone to adult, female big brown bats (Eptesicus fuscus) roosting in buildings in Fort Collins, Colorado. We used records from PIT readers at roosts to compute apparent annual survival of both groups from 2001 to 2003 and found them to be similar. All bats examined 1 year after radiotagging were reproductively active and had body masses similar to bats not radiotagged. Big brown bats do not appear to suffer from major long-term effects of carrying transmitters within the 5% rule.
Categories: Publication; Types: Citation; Tags: Journal of Mammalogy
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Single wolves (Canis lupus arctos), a pair, and a pack of five habituated to the investigator on an all-terrain vehicle were followed on Ellesmere Island, Northwest Territories, Canada, during summer. Their mean travel speed was measured on barren ground at 8.7 km/h during regular travel and 10.0 km/h when returning to a den.
Categories: Publication; Types: Citation; Tags: Journal of Mammalogy
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Abstract has not been submitted
Categories: Publication; Types: Citation; Tags: Journal of Mammalogy
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Based on global positioning system (GPS) radiocollars in northeastern Minnesota, deer migrated 23-45 km in spring during 31-356 h, deviating a maximum 1.6-4.0 km perpendicular from a straight line of travel between their seasonal ranges. They migrated a minimum of 2.1-18.6 km/day over 11-56 h during 2-14 periods of travel. Minimum travel during 1-h intervals averaged 1.5 km/h. Deer paused 1-12 times, averaging 24 h/pause. Deer migrated similar distances in autumn with comparable rates and patterns of travel.
Categories: Publication; Types: Citation; Tags: Journal of Mammalogy