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The grasslands of southwestern Saskatchewan, Canada are home to several snake species of conservation concern at the northern extreme of their geographic range. To aid conservation assessment and management planning for these snakes, we used radio‐telemetry, a geographic information system, and multivariate modeling to identify and compare macrohabitat selection by eastern yellow‐bellied racers (n = 33; Coluber constrictor flaviventris), bullsnakes (n = 16; Pituophis catenifer sayi), and prairie rattlesnakes (n = 23; Crotalus viridis). All 3 species shared communal hibernacula in the inactive winter season, but dispersed into different macrohabitats across the landscape during the spring and summer. Their home ranges varied in size by species and were dumbbell‐shaped with activity centers near hibernacula and in well‐defined summer grounds; activity centers were connected by narrow movement corridors. Racers strongly selected for riparian areas, bullsnakes selected for valley grassland habitats, and rattlesnakes selected for areas associated with prairie dog colonies. Some rattlesnakes traveled great distances (over 11 km) from the dens compared to the other species (bullsnake max. = 4 km; racer max. = 5 km), which may be a result of their selected macrohabitat being more patchily distributed in the landscape. Our results indicate that management plans for these snakes must consider the den area, corridors, and separate summering grounds, as well as differences in home range size and movement patterns for each species. © 2013 The Wildlife Society.

We validated a radioimmunoassay-based method quantifying fecal glucocorticoid metabolites (FGMs) from captive male and female Richardson’s ground squirrels Urocitellus richardsonii. Blood samples were drawn to explore the correlation between plasma cortisol and FGM concentrations. We also injected groups of squirrels with normal saline (CTL; control), adre-nocorticotropic hormone (ACTH; stimulating adrenal activity), or dexamethasone (DEX; suppressing adrenal activity). Potential correlations between stress and behaviour were explored through quantification of fecal pellet production and the intervention necessary to elicit defecation, as well as the behaviour of subjects in the context of handling. Changes in plasma cortisol concentration between capture (baseline), and following handling (stress-induced) were also quantified for free-living squirrels. While glucocorticoid concentrations recovered from feces during our captive-animal study were not well correlated with plasma cortisol concentrations, and uncorrelated with defecation or behaviour, FGM concentrations did reflect the activation of the hypothalamic-pituitary-adrenal (HPA) axis. FGM concentrations increased significantly during initial captivity, but declined to baseline level as individuals acclimated to the novel environment. Injection of subjects with ACTH increased FGMs above baseline, confirming activation of the HPA axis. Plasma cortisol concentrations increased significantly with induced stress, indicating that capture and handling activated the glucocorticoid stress response even among previously handled, free-living subjects. Our findings validate a non-invasive tool that will afford new insight into the physiological processes underlying social, reproductive and antipredator behaviour of Richardson’s ground squirrels.

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The relationship between stress and personality has often been studied using captive animals in a laboratory context, yet less often in wild populations. Wild populations, however, may reveal aspects of the personality–stress relationship that laboratory‐based studies cannot. Here, we assessed the personality and stress hormone response of adult females within a free‐living population of Richardson's ground squirrels (Urocitellus richardsonii). Personality was assessed by quantifying individual responses to a novel object, and physiological stress was measured from faecal glucocorticoid metabolites. Principal component and principal component regression analyses were performed to determine whether the behavioural and endocrine measures were related. Based on these analyses, shyness–boldness was found to best predict glucocorticoid levels, in that individuals expressing the greatest vigilance in response to the novel object also had the highest measured concentrations of faecal glucocorticoids. Exploration, however, was independent of measured glucocorticoid levels, consistent with a multidimensional interpretation of non‐human animal personality.

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On the North American Great Plains, several snake species reach their northern range limit where they rely on sparsely distributed hibernacula located in major river valleys. Independent colonization histories for the river valleys and barriers to gene flow caused by the lack of suitable habitat between them may have produced genetically differentiated snake populations. To test this hypothesis, we used 10 microsatellite loci to examine the population structure of two species of conservation concern in Canada: the eastern yellow-bellied racer (Coluber constrictor flaviventris) and bullsnake (Pituophis catenifer sayi) in 3 major river valleys in southern Saskatchewan. Fixation indices (FST) showed that populations in river valleys were significantly differentiated for both species (racers, FST = 0.096, P = 0.001; bullsnakes FST = 0.045–0.157, P = 0.001). Bayesian assignment (STRUCTURE) and ordination (DAPC) strongly supported genetically differentiated groups in the geographically distinct river valleys. Finer-scale subdivision of populations within river valleys was not apparent based on our data, but is a topic that should be investigated further. Our findings highlight the importance of major river valleys for snakes at the northern extent of their ranges, and raise the possibility that populations in each river valley may warrant separate management strategies.