Lion manes represent a compromise between social benefits and ecological costs. Mane development of Panthera leo varies geographically with prevailing climate, but varying genetics, behavior and social systems, and nutrition may all influence such broad-scale correlations. We studied captive lions housed comparably across 12 degrees of latitude in North America and correlated mane variation with climatic, life-history, and husbandry variables. As predicted from heat-load considerations, mane length and density were inversely correlated with temperature; color variation was unrelated. Mane development was correlated with January but not July conditions, suggesting a stronger response to cold than to heat. Climate-induced variation in manes of captives accounted for up to 50% of variation seen. Developmental effects of climate appear to be responsible for many of the taxonomic names applied to African lions and may signify important biological differences between modern and Pleistocene lions.

Marmots are the largest extant representatives of the squirrel family (Sciuridae). Members of this clade are believed to have conservative skeletal characters and are inclined to convergence in species with similar size and ecology. However, this does not seem to hold for the mandible and cranium of marmots; instead, similarities reflect subgeneric classification or geographic distribution. To understand the pattern of morphological evolution in the genus Marmota, the ontogeny of the cranium is investigated in 7 of the 14 living marmot species. In particular, the role of allometry in producing intra- and interspecific differences is analyzed. Sexual dimorphism in allometric trajectories is found to be negligible, whereas shape traits that characterize a specific age are mostly allometric. Allometry accounts for an important proportion, although not for the majority, of shape variation during postnatal ontogeny of the cranium. Interspecific differences in allometric trajectories are generally small and the majority of shape differences in relation to phylogeny appear early in ontogeny. Thus, allometry might have had a limited role in producing the morphological variation of living marmot species or it might even have constrained the range of evolutionary changes in this clade. A very different role of allometry as a source of morphological novelties can be speculated to exist in earlier stages of marmot evolutionary history, when a highly distinctive cranial shape evolved concomitant with a 2-fold increase in size. Three sets of analyses are performed to investigate the ontogeny of cranial form in Marmota. Three-dimensional (3D) coordinates of anatomical landmarks are used to describe the whole marmot cranium in the first 3D geometric morphometric analysis of a sciurid taxon. Also, anatomical landmarks that describe the dorsal and lateral sides of the cranium are used for 2-dimensional (2D) analyses complementary to previous studies on the ventral cranium. Despite the complexity of the cranium, which makes it a poor candidate for 2D studies, results of 2D and 3D analyses are generally in good agreement.

Measurement error can occur at both the intra- and interobserver level, result in significant biases in collected data, and increase the likelihood of type II errors. We estimated the intra- and interobserver measurement error associated with 4 commonly used and 1 modified external metric in 4 representative Australian small-mammal species, using both preserved laboratory specimens and live wild-caught individuals. Measurement error was larger in live individuals and was significant in a number of cases in metrics that were difficult to define, were highly flexible, or were relatively small. Observer experience significantly affected precision, and overall, our modified hind foot metric (length of the hind foot, excluding the toes) performed similarly to the currently used metric. The number of replicate measurements significantly affected the size of detectable differences between observers, and we recommend that at least 2 replicate measurements per metric be taken as a matter of course.

The taxonomy of gray four-eyed opossums, genus Philander, from northern South America is reviewed by means of comparative morphological and morphometric analyses. Two hundred eighteen specimens belonging to the following geographic samples were used: P. opossum opossum from French Guiana, Guyana, and Suriname; P. o. fuscogriseus from Central America and Colombia; P. andersoni from Colombia, Ecuador, Peru, and Venezuela; P. opossum from the Orinoco River delta (Venezuela); P. opossum from western Venezuela and eastern Colombia; and P. opossum from central Venezuela. Results obtained allow us to describe 2 new Philander species, one of which occurs in the floodplains of the Orinoco River delta and Paria Gulf (Venezuela), and the other of which is distributed in lowlands and uplands at the northern border of the Guiana Shield in Venezuela, as far as the Orinoco River, and foothills of Cordillera Oriental (Colombia) and Cordillera of Mérida (Venezuela). These new taxa were formerly considered to represent forms of P. opossum. In particular, it was suggested that specimens from the Orinoco delta constituted a subspecies of P. opossum, but this taxonomic pattern was not supported with detailed comparative analyses. Furthermore, the subspecific status of animals from western Venezuela and eastern Colombia was controversial and specimens from central Venezuela were considered as P. opossum but no empirical data supported this taxonomic identity. With respect to the other Philander species here considered, the 1st new species clearly differs in features concerning general skull shape and morphology, by its smaller skull size, relatively shorter tail, presence of a wide gray area in the underparts of the coat, and smaller and poorly defined supraorbital spots. The 2nd new species can be distinguished from the other Philander taxa by the general skull shape (relatively wide and short), specific skull traits, pale gray dorsum, and the characteristic coloration of ears (white with a wide black margin).

A new species of disk-winged bat (Thyroptera) is described from the savannah habitats of the Cerrado in Brazil and Rupununi in Guyana. It is most similar to the primarily forest-dwelling T. lavali because of shared morphology, including oval-shaped disks on the thumbs as opposed to circular disks in the other species (T. tricolor and T. discifera). However, the new species has distinct countershading with dark brown dorsal fur that is in contrast to pale brown ventral fur with frosted tips. The other species have either white or yellowish brown ventral fur. During the examination of comparative material for this description, some older material that was faded in color and previously reported as T. tricolor was assigned to T. discifera, representing a range extension of more than 1,000 km to the east and the 1st documentation of T. discifera in the Atlantic Forest of Brazil.

To. test for isolation by mountain ranges in small arboreal mammals, phylogeography of Pallas's squirrel .Callosciurus erythraeus) was investigated using complete mitochondrial control region sequences (1,079–1,081 bases). This common species is distributed in the low and middle elevations of Taiwan, Republic of China. We examined 71 specimens from 6 sites in 3 study regions divided by mountain ranges in Taiwan. The 43 haplotypes found in the Taiwan populations revealed association with geography. There were 4 main mitochondrial DNA phylogroups (northern, western, southern, and eastern), but 4 haplotypes were not included in any phylogroup. Distribution range of each phylogroup was similar to defined geological categories, suggesting mountain range isolation influenced populations of C. erythraeus. The 4 phylogroups may be the result of glacial refugia during the Pleistocene.

It has been hypothesized that, in species exhibiting natal philopatry, genetically related individuals would have home ranges closer to each other than those of unrelated individuals. Using radiotelemetry (2001–2003) and genetic data from 35 female Florida black bears (Ursus americanus floridanus), we tested the hypothesis that genetic relatedness among individuals influenced the spatial organization of home ranges. Genetic relatedness was negatively correlated with geographic distance between home ranges for each year and season (except autumn 2000), suggesting that genetically related individuals established home ranges closer to each other, whereas home ranges of unrelated females were geographically separated. Additionally, females that had overlapping core home ranges were more closely related than females whose home ranges did not overlap. These results are consistent with the hypothesis that genetic relatedness influences spatial organization of home ranges.

On 17 August 2004, 5 Gambian rats (Cricetomys gambianus; 2 males and 3 females) were collected on Grassy Key, Florida. Evidence obtained from this collection confirms the existence of the 1st North American established and reproducing Cricetomys population. This invasive rodent population could represent a new series of ecological threats to the native and endemic flora and fauna of southern Florida.

Fishers (Martes pennanti) were purportedly extirpated from Montana by 1930 and extant populations are assumed to be descended from translocated fishers. To determine the lineage of fisher populations, we sequenced 2 regions of the mitochondrial DNA genome from 207 tissue samples from British Columbia, Minnesota, Wisconsin, and Montana. In northwestern Montana, fishers share haplotypes with samples from the upper Midwest and British Columbia; in west-central Montana, we detected haplotypes found in British Columbia samples, but also detected a control region and cytochrome-b haplotype not found in source populations. Based on the unique haplotypes found in west-central Montana, we propose that individuals with these haplotypes are descended from a relic population. Fishers in northwestern Montana are likely descended from fishers from the Midwest and British Columbia.

Reintroduced populations are generally smaller and more isolated than native populations; thus even when reintroduced populations are demographically stable, a lack of genetic variation may present a threat to long-term persistence. We examined the demographic structure and genetic variation of the marten reintroduction into the Upper Peninsula of Michigan. Male : female and juvenile : adult female ratios indicate that the Michigan population is demographically stable. Michigan martens had higher allelic diversity (A = 7.4) compared to the average diversity found among Canadian populations (A = 5.8) and similar levels of observed heterozygosity (H_Canadian = 0.64, H_Michigan = 0.63), excluding Newfoundland martens. We found no significant differences in the allelic diversity or heterozygosity between the reintroduced Michigan population and the source population for the reintroduction, that of Chapleau, Ontario. Surprisingly, we found no evidence of a genetic bottleneck in the Michigan population. We suggest that the genetic success of this reintroduction is a result of the multiple reintroductions and subsequent intrastate translocations that mimicked gene flow. The success was further aided by the presence of small remnant populations that remained in Michigan, as evidenced by the presence of private alleles in Michigan.

Dispersal influences distribution and genetic structure of animal populations. Dispersal in expanding wolf (Canis lupus) populations is not well documented, especially in Europe, where no studies of dispersal based on marked wolves are available. We studied the dispersal of wolves in Finland, where a peripheral wolf population (160–180 animals) increased and expanded during 1998–2004. We equipped 60 wolves from 8 neighboring wolf pack territories with radio or GPS transmitters in east-central Finland during 1998–2004, and at least 30 wolves (50%) dispersed from the home territory. Additional information was collected by detecting the natal pack of captured wolves with multilocus microsatellite genotyping and paternity analysis. In the study area, the directions formed a sun-ray pattern. Wolves usually departed their home territory as pups and yearlings, and in unimodal seasonal fashion. The dispersal distance (median 98.5, range 35–445 km) did not differ by sex (P = 0.342). Long-distance travelers (>200 km) were found only among wolves that departed at the age of 10–12 months. Survival was linked to the direction of dispersal. All marked wolves that dispersed to reindeer management areas in the north were shot before being able to reproduce, whereas elsewhere, the majority of dispersers (10 of 16) reproduced.

Ground squirrels are often described as preferring open grassland habitats to increase their chances of locating predatory threats while visually surveying their surroundings. This description is often based on the assumption that ground squirrels require clear views to promote detection of predators. We studied a population of Uinta ground squirrels (Spermophilus armatus) inhabiting patches of grassland and sagebrush in the northern range of Yellowstone National Park to determine if the presence of view-obstructing vegetation would be associated with differences in vigilance behavior of individuals. We also compared rates of weight gain and population estimates in grassland and sagebrush patches to determine if these factors would vary in association with differences in time budgets and perceived risk of predation in these patch types. Although there were differences among sites in time spent foraging and maintaining vigilance, these differences were not consistent between sites of similar habitat and degree of visual obstruction. These results suggest that the relationship between visibility and vigilance for this species may be complicated by the dual nature of shrubs as visual obstructions and as protection from attacking predators. The relationship between these 2 factors will likely influence how prey species respond to alterations to the vegetative structure of their environments. Ground squirrels, specifically, appear to be capable of adapting to variation in the structure of the vegetation and will likely thrive as long as an abundance of grasses are available to provide fattening seeds for forage.

Black-tailed prairie dogs (Cynomys ludovicianus) were greatly reduced in number and range in the last century, which is of conservation concern because their activities promote habitat heterogeneity and enhance biodiversity in prairie ecosystems. Based on their behavioral ecology, we hypothesized that prairie dogs would expand into areas adjacent to active colonies where woody shrubs and other visual obstructions were reduced, and designed an experimental study to assess this possibility at Theodore National Park, North Dakota. A combination of controlled burns and brush removal was applied to 2-ha experimental plots at 3 different prairie dog study colonies where adjacent control plots were left untreated. Systematic behavioral observations and periodic colony mapping revealed a strongly disproportionate use of experimental compared to control plots by prairie dogs over a 1.5-year period. More prairie dogs ventured into experimental plots than into control plots and there were an average of 335 new burrows and a mean 50.3% expansion into experimental plot areas compared to an average of 69 new burrows and a mean 1.6% expansion in control plots. Our results indicate that it may be possible to facilitate restoration of black-tailed prairie dogs by habitat manipulations, ultimately benefiting multiple native species in prairie ecosystems.

We studied maternal care in Steller sea lions (Eumetopias jubatus) at a small rookery in the northern Gulf of Alaska over the course of 4 summers, 2001–2004 and 3 autumn seasons, 2002–2004, using remotely operated video cameras. Perinatal periods were long (≥10.0 days); although varied between years. Timing of parturition was earlier and perinatal periods longer for multiparous females compared to females considered to be primiparous. Summer foraging trip durations were short (X̄ = 16.5 h), increased during August, then did not change significantly over the course of the autumn (X̄ = 55.7 h). Individual lactating females spent a greater proportion of their time on shore during the summer and a greater proportion of their time at sea during the autumn. The amount of time that females nursed their pups also increased significantly from the summer to autumn. Long perinatal periods and short foraging trips during summer indicate that sea lions are likely finding sufficient food nearby. Our data also suggest that Steller sea lions reach an upper plateau in duration of foraging cycles as early as mid-August and large increases above that plateau may indicate difficulty finding sufficient food during the winter months.

Although a variety of species exhibit birth-site fidelity, examples from ungulate species are rare. We recorded birth-site locations of pronghorns (Antilocapra americana) at the National Bison Range in northwestern Montana during 2000–2004 and found that 82% of females changed locations from the previous year. Females that exhibited birth-site fidelity had successfully weaned more fawns and were less likely to have experienced a fawn mortality event in the previous year than females that changed birth sites. Females that weaned a single fawn or weaned 0 fawns were equally likely to change birth sites. There was a year effect on distribution of birth sites as well as on birth-site fidelity. Dry range conditions in 2003 after multiple years of low precipitation may have caused more females to move their birth sites to areas of greater forage availability. The low observed frequency of birth-site fidelity may be a result of high fawn mortality rates at the National Bison Range. Success in the previous year appears to be one of the environmental cues that pronghorn females use to select a birth site.

The thermal physiology of tree-roosting bats has been rarely studied in the wild. I used temperature telemetry to locate and record the skin temperature (T_skin) of chocolate wattled bats (Chalinolobus morio, Vespertilionidae) roosting in tree cavities. In summer, male C. morio (n = 4) used torpor on 88% (15 of 17) of days. Bats entered torpor before or near sunrise, remained torpid for 7.3 h ± 3.8 SD (range: 0.8–13.2 h), and aroused midmorning. Torpor bout duration was negatively related to minimum torpid T_skin (R² = 0.94, P < 0.001). In winter, a female bat employed prolonged torpor lasting 13.5 and 15 days, during which T_skin fluctuated passively by 5.7°C ± 2.5°C, following the daily temperature cycle. At the same time of year, a male bat used torpor repeatedly but aroused on most evenings, possibly to find and copulate with females and also forage on warmer nights. These data shows that male C. morio frequently enter torpor in summer and provides the 1st direct evidence of winter hibernation by tree-roosting bats.

Echolocation calls emitted by the 4 species of Cuban mormoopid bats were compared to determine vocal signatures that enable identification of each species in the field during their evening exodus. Echolocation calls produced by Mormoops blainvilli are downward frequency-modulated (FM) signals in the range of 68.4–52.5 kHz. Echolocation calls emitted by Pteronotus macleayii and P. quadridens have a similar design consisting of a short constant-frequency (CF) segment followed by a downward FM segment. The CF segment was at 70.0 kHz in calls from P. macleayii, and at 83.3 kHz in calls from P. quadridens. Echolocation calls from P. parnellii consist of a long CF segment, which is preceded by a short initial upward sweep and followed by a downward FM terminal sweep. The CF value of the 2nd harmonic was a good parameter for species identification. The features of the echolocation calls of each of the species were used to identify them during the evening exodus from 2 Cuban caves.

Behavioral patterns of animals correlate with biotic (i.e., resources and conspecifics) and abiotic (i.e., weather and lunar cycle) factors. We studied the influence of ambient light, rain, sex, and resource availability on the activity pattern of the neotropical chestnut short-tailed bat (Carollia castanea; Phyllostomidae) in a tropical lowland forest in Panama. Time of emergence was tightly correlated with local sunset, in contrast to the time of return, which occurred sporadically over a span of hours. Activity by individuals peaked at the beginning of the night, coinciding with maximum availability of ripe fruits from understory pepper plants (Piperaceae), their main food source. Bats continued to forage during light and moderate rain and only stopped at heavy rain. Nightly activity level was similar in nonreproductive female and male C. castanea but the temporal distribution of activity differed. Females were more active in the 1st half of night, whereas activity of males was more evenly distributed throughout the night. In contrast to fruit-eating bats in the canopy, C. castanea did not exhibit a significant reduction in flight activity (lunar phobia) during bright nights around the full moon. We conclude that ecological conditions (availability of food and predation risk) and physiological constraints (small body size associated with high metabolic rate) are the most important factors that account for the observed activity patterns.

We evaluated composition and seasonal variation in the diet of Rickett's big-footed myotis (Myotis ricketti) by examining 342 fecal samples collected every 2 weeks when the bats were active in Fangshan District of Beijing, North China, from 2002 to 2003. The diet consisted of 3 kinds of fish (Zacco platypus, Carassius auratus, and Phoxinus lagowskii) and at least 7 orders of insects (Coleoptera, Lepidoptera, Homoptera, Ephemeroptera, Hemiptera, Diptera, and Hymenoptera). Fragments of fish accounted for 67.1% and fragments of insects for 28% (by volume) of the diet; Z. platypus was the dominant food (60.1%), followed by Coleoptera (13.1%). Significant differences existed between the proportion of fish and insects in the diet; however, no seasonal variation in the diet was found over the course of the investigation. This suggests that at this study site in Beijing, M. ricketti was highly specialized in foraging on only 1 species of fish and relied less on insects as alternative food sources, despite their seasonally high abundance.

Previous studies of forest-dwelling bats have identified physical features of trees and forests that correlate with the presence of bats by comparing roost sites to paired, randomly selected sites. This method may be limited if the absence of bats from random sites cannot be confirmed. Our purpose was to address roosting ecology of female big brown bats (Eptesicus fuscus) using a different approach. We quantified relative use of trees with 3 different types of cavity openings (long crevices, multiple holes, or single holes) and compared the relative use of these potential roosts to the availability of each roost type in the study area. Bats used trees with multiple holes and crevices significantly more often than expected based on their availability and trees with single holes less often than expected. Crevice roosts had significantly larger cavities than did single holes and roosting-group size was positively correlated with cavity volume. No relationship was found between cavity volume and tree height or stem diameter of roost trees, 2 variables that have been reported to correlate with roost selection in other studies of forest bats. Examination of our data suggests that the volume of roost cavities may be an important selection criterion for colonial, forest-living bats and that standard interpretations of the roost versus random-tree approach may not accurately identify patterns of roost selection in some systems.

In an environment subjected to rapid anthropogenic alterations, the distribution and abundance of mammalian species often reflect their flexibility in habitat use. The northern bat (Eptesicus nilssonii) is patchily distributed in Germany, where it is classified as a critically endangered species, but is abundant in Scandinavia. To assess its flexibility in habitat use, we radiotracked 10 females and 3 males captured at a maternity roost in Lower Saxony, Germany, during the summers 2002–2003. These bats had access to a variety of habitats including pristine areas (unimproved grassland and forest) and anthropogenically altered habitats (pastures, euthrophic lakes, urban area). The widely overlapping home ranges had a median area of 524 ha. They extended asymmetrically around the maternity roost and reflected a preference for elevations around and below roost level, that is, 365 m elevation. Males traveled up to 70 km per night during exploring flights. E. nilssonii used forest habitats opportunistically before birth of the young and avoided them thereafter, whereas most bats preferred urban habitats and especially streetlamps after births. Intraspecific encounters were more frequent after births, particularly around streetlamps, suggesting an increased intraspecific competition at these sites. Interestingly, females spent 27% but males only 3% of their foraging time hunting with conspecifics. Thus, the species is a habitat generalist for which urban areas provide a supplementary seasonal habitat. However, because such habitats may not always remain profitable, natural habitats of forest and grassland will remain essential to the survival of this bat species in Germany.

Individuals of some species of bats roost in human-made structures despite the apparent availability of natural roosts. We compared patterns of thermoregulation in relation to microclimate and compared reproductive timing for maternity colonies of big brown bats (Eptesicus fuscus) roosting in natural and building roosts in the prairies of southeastern Alberta. During pregnancy, bats roosting in buildings used torpor less frequently than did rock-roosting bats, but achieved lower body temperatures when torpid. Less-frequent use of torpor leaves more active days for fetal development, and bats in building roosts gave birth earlier than those in rock roosts. We observed predators and predation in rock roosts, but not in building roosts, and suggest that bats roosting in rocks use shallower torpor to remain vigilant. Patterns of torpor use suggest that bats in buildings save more energy than rock-roosting individuals by roosting in the warmer microenvironments of buildings and by achieving lower body temperatures when ambient conditions are cold and foraging is not productive. The warmer building roosts are also conducive to juvenile growth, and young building-roosting bats fledged 1–2 weeks before rock bats. We propose that advantages for bats roosting in buildings (lower predation risk, earlier births, faster juvenile growth rates, and increased energy savings) lead to greater long-term reproductive success for building-roosting bats and make buildings preferred roosts.

We studied bushy-tailed woodrats (Neotoma cinerea occidentalis) in the eastern Washington Cascade Range to estimate their density and survival in 3 typical dry forest cover types. We predicted woodrat density to be high, moderate, and low in mature mixed-conifer forests, young mixed-conifer forests, and open ponderosa pine forests, respectively. We livetrapped on 8 × 8 grids (280 m) over an 8-day period each autumn for 4 years to obtain Huggins mark–recapture estimates of woodrat density. We captured woodrats 617 times and marked 193 individual woodrats in 12 sample stands during 42,165 trap nights. The sex ratio of captures was 62% female and 38% male. Adults made up 79% of captures. Woodrat density averaged 0.49 animals/ha among all cover types and years; woodrat density did not differ among types. Regardless of cover type, stands fell into 4 woodrat-density groups, with densities ranging from 0.13 to 0.93 woodrats/ha. Classification tree analysis revealed that woodrat-density groups could be predicted well (proportional reduction in error = 0.73 to 0.89) by the type and amount of cover provided by large snags, mistletoe brooms, and soft downed logs. Over the 4-year period, woodrat density ranged from 0.28 animals/ha to 0.87 animals/ha, increasing each year at a rate of λ = 1.8 consistently among cover types. A moderate (r = 0.55) density-dependent response in per capita rate of increase was detected. The apparent annual survival rate was a low 0.14. Management to reduce woody fuels and to restore low-intensity high-frequency fire regimes in ponderosa pine and dry Douglas-fir forest likely will reduce bushy-tailed woodrat populations unless prescriptions can mitigate the loss of snag, mistletoe, and downed log cover.

Sex differences in reproductive investment influence space use patterns of many animals. In polygynous mammals, male space use reflects distribution of females and female space use reflects relative distribution of food. We used radiotelemetry to examine seasonal patterns of home-range size, overlap, and distance traveled by male and female Chiricahua fox squirrels (Sciurus nayaritensis chiricahuae) from 2002 to 2003. Male and female home-range and core-area size varied little between nonmating and mating seasons. Female core areas had a greater percentage overlap by males than by females during mating and nonmating seasons. Males traveled farther in the mating season and females showed little variation between seasons. Extreme spatial and temporal fluctuations of food experienced by Chiricahua fox squirrels may result in space use patterns that differ from those of tree squirrels living in forests with a greater abundance of food.

We studied factors associated with occurrence of high-amplitude population fluctuations of the prairie vole (Microtus ochrogaster) in alfalfa, bluegrass, and tallgrass habitats in east-central Illinois for 25 years. Increased survival was the most important factor associated with initiation of a population fluctuation during a given year. The proportion of reproductively active adult females was not associated with initiation of population fluctuations. The interval between fluctuations was not correlated with the previous peak density. We propose that population fluctuations in M. ochrogaster were initiated by the net effects of relaxation of predation pressure of multiple generalist predators, which occurred erratically across years.

The spacing patterns and mating systems of solitary carnivores have important implications for social behavior and for the survival and reproduction of individuals. Over 2 years, we reintroduced 32 (15 males and 17 females) bobcats (Lynx rufus) to a barrier island off the coast of Georgia and studied patterns of bobcat spatial distribution. Population density increased to 3.1 bobcats/10 km². We found overlap of the home range for all females on the island increased during 1989–1991 such that, on average, each female shared a home-range area with the equivalent of >2 other females, and for core areas overlap was equivalent to sharing a core area with nearly 1 other female. Reproduction and home-range overlap were related inversely and food resources did not seem to be limiting. Our results were consistent with the land tenure concept in that the initial reintroduced bobcats established home ranges that changed little in size and location. However, bobcats resident on the island for ≥1 year did not successfully exclude newcomers from their home ranges or core areas and no bobcats retained areas of exclusive use from conspecifics of the same sex. We suggest that the propensity of female bobcats to reproduce successfully may be related to their access to exclusive use areas even under conditions of adequate or good food availability. Under the conditions in this study (moderate bobcat density, adequate food availability, and limited dispersal) bobcats exhibited no evidence of an ability to exclude other adult individuals from their home ranges or core areas.

Effective management strategies require an understanding of the spatial scale at which fauna use their habitat. Toward this end, we sampled small mammals in the northern Sierra Nevada, California, over 2 years at 18 livetrapping grids among 5 forest types. Forest types were defined by overstory tree composition, and 19 microhabitat variables were measured at all trap stations. Forest type and year explained 93% of variation in abundance of North American deermice (Peromyscus maniculatus), whereas only 40% was explained by microhabitat and year. Similarly, variation in abundance of long-eared and shadow chipmunks (Neotamias quadrimaculatus and N. senex) was better explained by forest type and year (67%) than by microhabitat and year (30%). Red fir (Abies magnifica) forests supported more P. maniculatus and Neotamias species than mixed-conifer and pine–cedar forests, and more Neotamias species than mixed-fir forests. Five of 6 uncommon species were significantly associated with forest type; golden-mantled ground squirrels (Spermophilus lateralis), northern flying squirrels (Glaucomys sabrinus), and long-tailed and montane voles (Microtus longicaudus and M. montanus) were captured almost exclusively in red fir forests, whereas dusky-footed woodrats (Neotoma fuscipes) and California ground squirrels (Spermophilus beecheyi) were found in pine–cedar, mixed-fir, and mixed-conifer forests. The first 2 axes of a canonical correspondence analysis on microhabitat variables explained 71% of variation in combined small mammal abundance. Microhabitat associations varied among species but were driven primarily by canopy openness, shrub cover, and shrub richness. Although much of the small mammal fauna appeared to select habitat at both spatial scales studied, canonical correspondence analysis using forest type as a covariate revealed that microhabitat explained much less variation in small mammal abundance than did forest type.