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Whitehorse, Canada

Jung T.S.,Environment Canada | Slough B.G.,35 Cronkhite Road
American Midland Naturalist | Year: 2011

We captured a free-ranging adult female little brown bat (Myotis lucifugus) with a fractured humerus that was in an advanced stage of healing. Compared to seven other adult female little brown bats captured the same evening from the same colony, the body condition of the bat with the healing humerus was 5.4%-13.8% less than other colony members. Our observation suggests that even though free-ranging bats may survive the trauma associated with a broken wing bone, there may be latent effects on their ability to forage and maintain body condition. This may ultimately compromise their ability to build up sufficient energetic reserves to migrate and hibernate. © 2011, American Midland Naturalist. Source


Jung T.S.,Environment Canada | Slough B.G.,35 Cronkhite Road | Nagorsen D.W.,Mammalia Biological Consulting | Kukka P.M.,Environment Canada
Canadian Field-Naturalist | Year: 2014

The Ogilvie Mountain Collared Lemming (Dicrostonyx nunatakensis Youngman, 1967), reported only from the Ogilvie Mountains of central Yukon, is among the least known mammals in Canada. It was first discovered in 1961 and, since then, only 13 specimens had been collected, all from one mountain, in central Yukon. We conducted a targeted survey to determine the distribution of the species by trapping areas of apparently suitable habitat on 12 mountains within 40 km of the known location. Many of our traps were disabled by other mammals; however, we captured three Ogilvie Mountain Collared Lemmings on two mountains 25.9 km and 29.6 km from the original location. Our findings suggest that this lemming may be more widely distributed than indicated by earlier specimens. We suggest further surveys to delineate the range of the Ogilvie Mountain Collared Lemming. © 2014, Canadian Field-Naturalists' Club. All rights reserved. Source


Gallant D.,University of Quebec at Rimouski | Reid D.G.,Wildlife Conservation Society | Slough B.G.,35 Cronkhite Road | Berteaux D.,University of Quebec at Rimouski
Polar Biology | Year: 2013

In the twentieth century, red fox (Vulpes vulpes) expanded into the Canadian Arctic, where it competes with arctic fox (Vulpes lagopus) for food and shelter. Red fox dominates in physical interactions with the smaller arctic fox, but little is known about competition between them on the tundra. On Hershel Island, north Yukon, where these foxes are sympatric, we focused on natal den choice, a critical aspect of habitat selection. We tested the hypothesis that red fox displaces arctic fox from dens in prey-rich habitats. We applied an approach based on model comparisons to analyse a 10-year data set and identify factors important to den selection. Red fox selected dens in habitats that were more prey-rich in spring. When red foxes reproduced, arctic fox selected dens with good springtime access, notably many burrows unblocked by ice and snow. These provided the best refuge early in the reproductive season. In the absence of red foxes, arctic foxes selected dens offering good shelter (i.e. large isolated dens). Proximity to prey-rich habitats was consistently less important than the physical aspects of dens for arctic fox. Our study shows for the first time that red foxes in the tundra select dens associated primarily with prey-rich areas, while sympatric arctic foxes do not. These results fit a model of red fox competitively interfering with arctic fox, the first detailed study of such competition in a true arctic setting. © Springer-Verlag Berlin Heidelberg 2013. Source


Gallant D.,University of Quebec at Rimouski | Slough B.G.,35 Cronkhite Road | Reid D.G.,Wildlife Conservation Society | Berteaux D.,University of Quebec at Rimouski
Polar Biology | Year: 2012

During the last century, the red fox (Vulpes vulpes) has expanded its distribution into the Arctic, where it competes with the arctic fox (Vulpes lagopus), an ecologically similar tundra predator. The red fox expansion correlates with climate warming, and the ultimate determinant of the outcome of the competition between the two species is hypothesized to be climate. We conducted aerial and ground fox den surveys in the northern Yukon (Herschel Island and the coastal mainland) to investigate the relative abundance of red and arctic foxes over the last four decades. This region has undergone the most intense warming observed in North America, and we hypothesized that this climate change led to increasing dominance of red fox over arctic fox. Results of recent surveys fall within the range of previous ones, indicating little change in the relative abundance of the two species. North Yukon fox dens are mostly occupied by arctic fox, with active red fox dens occurring sympatrically. While vegetation changes have been reported, there is no indication that secondary productivity and food abundance for foxes have increased. Our study shows that in the western Arctic of North America, where climate warming was intense, the competitive balance between red and arctic foxes changed little in 40 years. Our results challenge the hypotheses linking climate to red fox expansion, and we discuss how climate warming's negative effects on predators may be overriding positive effects of milder temperatures and longer growing seasons. © 2012 Springer-Verlag. Source

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