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Summary Predicting the spatial pattern of disease risk in wild animal populations is important for implementing effective control programmes. We developed a risk model predicting the probability that a deer harvested in a wild population was chronic wasting disease positive (CWD+) and evaluated the importance of landscape connectivity based on deer movements. We quantified landscape connectivity from deer ‘resistance’ to move across the landscape similar to the flow of electrical current across a hypothetical electronic circuit. Resistance values to deer movement were derived as the inverse of step selection function values constructed using movement data from GPS-collared deer. The top CWD risk model indicated risk increased over time was higher among mule deer Odocoileus hemionus than white-tailed deer Odocoileus virginianus, males than females, and was greater in areas with high stream density and abundant agriculture. A metric of connectivity derived from mule deer movements outperformed models including Euclidean distance, with high connectivity being associated with high CWD risk. The CWD risk model was a good predictor of CWD occurrence among an independent set of surveillance data collected in subsequent years. Synthesis and applications. We found that landscape connectivity was a major contributor to the spatial pattern of chronic wasting disease (CWD) risk on a heterogeneous landscape. For this reason, future disease surveillance programmes and models of disease spread should consider landscape connectivity. In the aspen parkland ecosystem, we recommend managers focus surveillance and control efforts along river valleys surrounded by agriculture where mule deer abound, because of the high risk of CWD infection.

Two hundred and ninety-one ticks (i.e., 185 larvae, 72 nymphs, and 34 adults) were removed from 153 small mammals comprising six species collected in Verdant Forest, Numa Forest, and Marble Canyon within Kootenay National Park, British Columbia, Canada. Morphological examination and molecular analyses (i.e., polymerase chain reaction-single-strand conformation polymorphism [PCR-SSCP] and DNA sequencing of the mitochondrial 16S rRNA gene) of the ticks revealed that most individuals were Ixodes angustus Neumann. All life cycle stages of I. angustus were found primarily on southern red-backed voles, Clethrionomys gapperi (Vigors). Two Dermacentor andersoni Stiles females were also found on these small mammals. The results of the molecular analyses also revealed that there were three 16S haplotypes of I. angustus and two 16S haplotypes of D. andersoni. A comparison of available sequence data suggests genetic divergence between I. angustus near the western and eastern limits of the species distributional range in North America. Additional studies are needed to determine whether there are genetic differences between I. angustus from North America, Japan, and Russia, and whether there is geographical variation in the ability of ticks to transmit pathogens to their mammalian hosts.

Chronic wasting disease (CWD) is a fatal disease of North American cervids that was first detected in a wild, hunter-shot deer in Saskatchewan along the border with Alberta in Canada in 2000. Spatially explicit models for assessing factors affecting disease detection are needed to guide surveillance and control programs. Spatio-temporal patterns in CWD prevalence can be complicated by variation in individual infection probability and sampling biases. We assessed hunter harvest data of mule deer (Odocoileus hemionus) and white-tailed deer (Odocoileus virginianus) during the early phases of an outbreak in Saskatchewan (i.e., 2002-2007) for targeting the detection of CWD by defining (1) where to look, and (2) how much effort to use. First, we accounted for known demographic heterogeneities in infection to model the probability, P(E), that a harvested deer was infected with CWD given characteristics of the harvest location. Second, in areas where infected deer were harvested we modelled the probability, P(D), of the hunter harvest re-detecting CWD within sample units of varying size (9-54 km(2)) given the demographics of harvested deer and time since first detection in the study area. Heterogeneities in host infection were consistent with those reported elsewhere: mule deer 3.7 timeswhite-tailed deer, males 1.8 timesfemales, and quadratically related to age in both sexes. P(E) increased with number of years since the first detection in our study area (2002) and proximity to known disease sources, and also varied with distance to the South Saskatchewan River and small creek drainages, terrain ruggedness, and extent of agriculture lands within a 3 km radius of the harvest. The majority (75%) of new CWD-positive deer from our sample were found within 20 km of infected deer harvested in the previous year, while approximately 10% were greater than 40 km. P(D) modelled at 18 km(2) was best supported, but for all scales, P(D) depended on the number of harvested deer and time since the first infected deer was harvested. Within an 18 km(2) sampling unit, there was an 80% probability of detecting a CWD-positive deer with 16 harvested deer five years after the initial infected harvest. Identifying where and how much to sample to detect CWD can improve targeted surveillance programs early in the outbreak of the disease when based on hunter harvest.

Cestodes from Clethrionomys gapperi (n ¼ 34) and Microtus longicaudus (n ¼ 8) from Kootenay National Park, British Columbia, Canada are reported. Two species of cestodes, Hymenolepis horrida (sensu lato) and Catenotae- nia peromysci, were found in Clethrionomys gapperi, and 1 species of cestode, H. horrida, was found in Microtus longicaudus. Clethrionomys gapperi represents a new host record for C. peromysci. The Canadian Rockies is a new locality record for both cestode species.

Assessment of the body composition and body condition of animals in the wild is an important aspect of animal ecology. We were interested in understanding the seasonal changes in body condition in order to investigate the effects of adaptive strategies on life histories of animals. We investigated the merit of morphometric condition indices and bioelectrical impedance analysis (BIA) to predict fat reserves in striped skunks (Mephitis mephitis, n = 26). We took BIA and morphometric measurements following chemical immobilization in the field and completed chemical analyses of whole carcasses postmortem. We determined relationships between body lipid and water using multiple linear regression techniques and performed model selection using Akaike's Information Criterion (AIC). Bioelectric volume (L2/Rs) and chest circumference (CC) best predicted total body water (TBW=–1.1+0.058*CC+0.25 * L2/Rs; r2 = 0.91, SEE=0.15, P

The striped skunk (Mephitis mephitis) is the focus of research interest for a variety of reasons, including its roles as a rabies reservoir, urban pest, predator of bird eggs, and parasite host. Some research programmes may require husbandry and breeding of captive animals, and because skunks are inactive in the winter in northern environments, special methods are needed to maintain the animals over winter. We report on the establishment of a colony of striped skunks kept in captivity in the northern part of their range. Our goals were to develop simple and effective methods to keep skunks in captivity over winter, and successfully breed skunks in a manner that resembles conditions in the wild. In the spring of 2002, three wild-caught, pregnant females gave birth in captivity (mean litter size=7). During the first year, 11 of 12 females kept in captivity over winter reproduced successfully in the spring of 2003, with a mean litter size of 5.5 (range=4–8, n=11). In the summer of 2003, 91 of 93 juveniles (97.9%) survived >60 days past weaning. Our high survival and reproduction rates testify to the success of this program, and provide insights into the husbandry of a species that is inactive during winter. Zoo Biol 24:83–91, 2005. © 2005 Wiley-Liss, Inc.

A total of 20 (14 females, six males) captive striped skunks (Mephitis mephitis) with miniature temperature dataloggers implanted free in the abdominal cavity were examined for reproductive performance and pathology because of implants. Eleven of 12 female skunks reproduced successfully 45.9 ± 3.7 days after surgery to remove implanted dataloggers. The pregnancy rate of 91.7% (11/12) was much higher than other captive studies and was comparable with that of wild skunks. Eight striped skunks (six males, two females) that were euthanatized and necropsied after having implants in the abdominal cavity for 5 mo showed no apparent pathology associated with the implant. Implantation of the intraperitoneal devices did not lead to complications in abdominal tissues. Neither implant nor surgery affected reproduction. We conclude that implanted dataloggers can safely be used in physiologic studies of striped skunks or possibly other small carnivores in captive or field studies.

Three radio-collared striped skunks (Mephitis mephitis) found dead during a field study of winter ecology of striped skunks near Willowbrook, Saskatchewan, Canada were examined. Streptococcus equisimilis was identified as the primary agent causing necrotizing purulent pneumonia in one skunk and suppurative meningoencephalitis in another. Both Streptococcus equisimilis and Streptococcus canis were isolated from lesions of purulent myocarditis and pyothorax in the third skunk. These are apparently the first reported cases of S. equisimilis infection in striped skunks and suggest that this opportunistic pathogen may be a significant cause of mortality under some conditions.

We assessed patterns and energetic consequences of different overwintering strategies, torpor, and social thermoregulation in the striped skunk (Mephitis mephitis) under natural ambient temperature and photoperiod. Striped skunks entered spontaneous daily torpor, with the lowest torpid body temperature (T(b)) reaching 26.0 degrees C, the lowest recorded T(b) for a carnivore. Patterns of daily torpor differed between solitary and grouped skunks: all solitary skunks regularly entered daily torpor, but only some individuals in communal dens employed torpor. When they did, it was shallow and infrequent. Solitary skunks entered torpor on average 50 times (in 120 d) compared with 6 times for grouped skunks. During torpor, solitary skunks had average minimum T(b) of 26.8 degrees C and bout duration of 7.8 h, whereas grouped skunks had average minimum T(b) of 30.9 degrees C and bout duration of 5.4 h. Torpor by solitary skunks occurred during their activity phase, but grouped skunks' shallow torpor bouts were restricted to their diurnal resting phase. On average, grouped skunks experienced lower percent daily fat loss, and they emerged in spring with higher percent body fat of 25.5%. In contrast, solitary skunks emerged in spring with only 9.3% body fat. In conclusion, the use of daily torpor and social thermoregulation in northern populations of striped skunks represent two strikingly different mechanisms to minimize energetic costs and increase individual fitness in response to unfavorable environmental conditions.

We compared the effects of absence and presence introduced Eastern Grey Squirrels (Sciurus carolinensis) on the demography of native Douglas’s Squirrels (Tamiasciurus douglasii) in two urban parks in Vancouver, British Columbia: Ecological Reserve #74 in Pacific Spirit Regional Park (Douglas’s Squirrel only) and Stanley Park (Douglas’s and Eastern Grey squirrels). Based on the exploitative competition hypothesis, we predicted that in the presence of introduced Eastern Grey squirrels, Douglas’s Squirrels would occur at lower densities, have larger home ranges, lower body mass, and poorer reproduction. Using mark-recapture methods, we found no differences in density, home range, or body mass of Douglas’s Squirrel between parks. However, the proportion of breeding Douglas’s Squirrels was higher in Ecological Reserve #74 in the absence of Eastern Grey Squirrel, than in Stanley Park. We found no evidence that Eastern Grey Squirrels are displacing Douglas’s Squirrels in Stanley Park, but less conspicuous negative effects such as reduced breeding propensity may still reflect the competitive interactions of the two squirrel species.