Search for: All records

Abstract Small mustelids are difficult to survey due to their low density and cryptic nature. Population status of North American weasels (Mustela erminea,Mustela nivalis, andNeogale frenata) are believed to be in decline, but there are no standardized monitoring protocols to evaluate their status. To support weasel monitoring, we compared the attractiveness of various combinations of baits and lures to weasels in sites located throughout the eastern and central USA. We baited a total of 122 clusters of 4 camera traps, across 14 states, with random combinations of 4 baits and 3 scent lures in the winters of 2022 and 2023. Cameras baited with meat were 3.5 times more likely to detect both short‐ and long‐tailed weasels on average (mean percentage of cameras detecting weasels: 20–30%) than those with scent lures (3–11%). Red meat was twice as effective at attracting short‐tailed weasels (50%) as chicken or cat food (20%; Z = 2.49,p < 0.01). While red meat marginally increased detections of long‐tailed weasels (21%) compared to chicken and cat food (19%), its effectiveness was influenced by whether the bait was stolen (Z = 2.08,p = 0.04). Additionally, long‐tailed weasels were detected in half the time when raw chicken was used (median days to detection: red meat = 39.5 days, raw chicken = 14.5 days). When salmon oil was added to meat bait, it increased the likelihood of detecting short‐tailed weasels and reduced the time to detection for both species. A variety of non‐target species stole meat bait during the survey, making the camera traps less effective. The addition of salmon oil may have allowed for continual attraction of weasels until stolen meat bait could be replenished. In summary, red meat was the best all‐purpose bait for weasels, although raw chicken is similarly effective for long‐tailed weasels, and the addition of salmon oil is helpful. We also recommend a specific bait enclosure design that was the most effective at minimizing theft of bait. We propose our baiting strategy can be used as a survey standard to evaluate the distribution and population status of weasels. 

Abstract Urbanization is a persistent and widespread driver of global environmental change, potentially shaping evolutionary processes due to genetic drift and reduced gene flow in cities induced by habitat fragmentation and small population sizes. We tested this prediction for the eastern grey squirrel (Sciurus carolinensis), a common and conspicuous forest‐dwelling rodent, by obtaining 44K SNPs using reduced representation sequencing (ddRAD) for 403 individuals sampled across the species' native range in eastern North America. We observed moderate levels of genetic diversity, low levels of inbreeding, and only a modest signal of isolation‐by‐distance. Clustering and migration analyses show that estimated levels of migration and genetic connectivity were higher than expected across cities and forested areas, specifically within the eastern portion of the species' range dominated by urbanization, and genetic connectivity was less than expected within the western range where the landscape is fragmented by agriculture. Landscape genetic methods revealed greater gene flow among individual squirrels in forested regions, which likely provide abundant food and shelter for squirrels. Although gene flow appears to be higher in areas with more tree cover, only slight discontinuities in gene flow suggest eastern grey squirrels have maintained connected populations across urban areas in all but the most heavily fragmented agricultural landscapes. Our results suggest urbanization shapes biological evolution in wildlife species depending strongly on the composition and habitability of the landscape matrix surrounding urban areas.