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Pleistocene climate fluctuations rearranged ecosystems, and influenced the contemporary distribution of modern species. Although specialist species were often restricted to isolated refugia by Pleistocene climate change, generalist species may have been less constrained in their distribution and movements. We used a combination of genetic data and previously published fossil data to investigate the phylogeography and contemporary population structure of a generalist species, the striped skunk (Mephitis mephitis). We sequenced a portion of the mitochondrial cytochrome-b gene (601 base pairs) and amplified 8 microsatellite loci from 314 striped skunk specimens. Phylogenetic analysis of the cytochrome-b gene revealed the presence of 4 distinct phylogroups, and examination of microsatellite data indicated a pattern of secondary contact among these clades. We infer from these data that during the Rancholabrean stage prior to the Illinoian glaciation, striped skunks emerged from a southern refugium in the Texas-Mexico region and colonized the southeastern United States, forming a 2nd, later refugium in the east. This colonization was followed by a 2nd dispersal event from the southern source population to west of the Rocky Mountains during the Illinoian glacial period. During the Sangamonian interglacial stage, 2 distinct subclades formed on either side of the Sierra Nevada. During the Holocene, the subclade that colonized the Great Basin then expanded east across the northern Rockies and recolonized the Great Plains to create an area of secondary contact with the southern phylogroup. Secondary contact occurred to a lesser extent with individuals from the eastern phylogroup east of the Mississippi River. It appears that periodic Pleistocene glacial expansions and retreats caused a series of range expansions and secondary contact events in this native North American species to create a complex pattern of population structure today. [ABSTRACT FROM AUTHOR]

Multicomponent aposematic warning signals are generally accepted to function as a deterrent to predatory attacks; however, the relative importance of specific visual cues used by wild predators to recognize defended animals is poorly understood. Here, I use naturally and reciprocally colored taxidermy models of striped skunks (Mephitis mephitis) and gray foxes (Urocyon cinereoargenteus) to explore the impact of aposematic coloration and body shape on the behavior of wild mammalian predators. Models were baited, and all visiting species were recorded with remote video cameras at 10 wilderness sites in California, USA. I found that mammalian predators not only approached black-and-white models more hesitantly than gray-colored models but also reacted negatively to skunk-shaped models, suggesting that predators may generalize noxious qualities to both skunk coloration and skunk shape. This study also found an effect of skunk abundance on animal behavior with predators less likely to visit black-and-white models and more hesitant in their approach to skunk-shaped models at sites with greater skunk abundance. These findings suggest that prior experience and the frequency with which aposematic prey are encountered in a landscape are important predictors of predator avoidance of defended prey. [ABSTRACT FROM PUBLISHER]

We examined den-site selection patterns for western spotted skunks (Spilogale gracilis) and striped skunks (Mephitis mephitis) co-occurring in mesquite brushland of Tom Green County, Texas. Sixteen S. gracilis and 14 M. mephitis were radiocollared to locate den sites from October 2001 through June 2003. Characteristics of dens were assessed using 23 habitat variables. S. gracilis favored den sites with dense mesquite (Prosopis glandulosa), shrubs, and cacti (Opuntia), whereas M. mephitis used these areas but also more open habitats. Den habitats of S. gracilis were more uniform than were those of M. mephitis, implying that S. gracilis is more specialized in den-site selection. Both species used multiple den sites, both above and below ground, rather than a primary den. Aboveground denning occurred year-round for both species. For S. gracilis, 56% (n = 60) of dens were above ground, but denning was more common above ground in the spring and summer. Aboveground denning was more common than belowground denning for M. mephitis in all seasons, representing 64% (n = 50) of all dens. Den habitat analysis suggests that S. gracilis, unlike M. mephitis, may be limited to areas with sufficient cover, including prickly pear cactus, for denning. [ABSTRACT FROM AUTHOR]

Identifying factors that are limiting to populations is fundamental to understanding population dynamics of wildlife, and such knowledge is important for conservation and management. I compared survival and cause-specific mortality patterns between urban and rural populations of striped skunks (Mephitis mephitis) in northeastern Illinois. Rabies, an important mortality factor for skunks, was absent from the study populations. Body weights of skunks declined during winter in both areas, but there was a slightly greater decline for rural skunks. Estimates of annual survival were similar (P > 0.1) between areas, as were seasonal patterns of survival. Disease or poor physical condition was the greatest cause of mortality at the urban site throughout the year, whereas it was the most common mortality factor at the rural site only during winter and spring; vehicle collision was the most common cause of death at the rural site during summer and autumn. I found little evidence that body weight or condition before winter denning, sex, or age were related to survival during winter; however, relationships between these covariates and survival may have been obfuscated by parasites. Results from this study suggest that the winter season is a critical period for survival for skunks from rural and urban areas at temperate climates, anthropogenic factors associated with urban landscapes have minimal effects on skunk survival distributions, and disease is a major cause of mortality even in the absence of rabies. [ABSTRACT FROM AUTHOR]

The association of microhabitat variables and capture (= occurrence) of striped skunks (Mephitis mephitis) was assessed at 3 sites in western Tennessee. Sixteen features were included in univariate and stepwise logistic regressions lo investigate relationships between occurence and habitat factors and to construct models predictive of occurrence. Accuracy of models was examined using jackknife procedures, and maps predictive of occurrence were developed through semi variance and kriging analyses. Average height of stand, hardwood snags > 35 cm diameter at breast height, number of steins, distance to permanent water sources, and distance to open areas were among the habitat features most frequently found to be related to occurrence. Models derived from logistic regression predicted occurrence of the species at varying levels (56% to 75%). Overall, classification percentages appeared to be at a level useful for predicting the occurrence of M. mephitis, and mapping procedures sufficient for illustrating the association between occurrence and habitat. [ABSTRACT FROM AUTHOR]

Mammalian predation influences waterfowl breeding success in the U.S. northern Great Plains, yet little is known about the influence of the landscape on the ability of predators to find waterfowl nests. We used radiotelemetry to record nightly movements of red foxes (Vulpes vulpes) and striped skunks (Mephitis mephitis) in two 41.4-km² study areas in North Dakota. Study areas contained either 15-20% grassland (low grassland composition) or 45-55% grassland (high grassland composition). Grasslands included planted cover, pastureland, and hayland. We predicted that the type and composition of cover types in the landscape would influence both predator movement across the landscape (as measured by the fractal dimension and displacement ratio) as well as localized movement (as measured by the rate of movement and turning angle between locations) within patches of different cover types. Red fox movements were straighter (lower fractal dimensions and higher displacements) across landscapes with a low grassland composition, indicating directed movement between the more isolated patches of planted cover. Striped skunk movements did not differ between landscape types, illustrating their movement along wetland edges, which had similar compositions in both landscape types. The high variability in turning angles by red fox in planted cover and pastureland in both landscape types is consistent with restricted-area foraging. The high rate of movement by red foxes in planted cover and by striped skunks in wetland edges suggests that spatial memory may influence movement patterns. Understanding the behavior of predators in fragmented prairie landscape is essential for managing breeding habitat for grassland birds and for predicting the spatial and temporal dynamics of predators and their prey. [ABSTRACT FROM AUTHOR]