Grey fox (Urocyon cinereogenteus) COSEWIC assessment and update update status report: chapter 13

Summary of status report

The grey fox, Urocyon cinereoargenteus, was once a relatively common species in southern Ontario in pre-European times. It disappeared from Canada just prior to the arrival of Europeans and only reappeared in the late 1930s or early 1940s. There are likely fewer than 250 mature grey foxes in Canada, but much uncertainty remains about their population size, trends and geographical distribution. Human harvest (trapping and hunting) is the most important factor limiting U.S. grey fox population; however, the importance of harvest on grey foxes in Canada is unknown. Climate change has been speculated to be an important factor determining the grey fox’s range (i.e. warming trend causing a northward range expansion and vice versa). Disease, specifically canine distemper and rabies, which are both enzootic in North America, has the potential to limit grey fox populations. Another factor that could potentially pose a threat to grey foxes in Canada is road mortality, but until data on the frequency of occurrence of this factor is collected, its real effect remains unknown. Populations in the Great Lakes and northeastern regions of the United States have, in the past, repopulated Canadian territory and may do so again should the grey fox be extirpated from Canada.

The status designation of Vulnerable (now Special Concern) assigned in 1979, for reasons of: cold and dry climate, agricultural development, and predators (coyotes when numerous) (Steers 1979), does not appear justified. If current predictions about global warming are correct, the climate of Canada will become more attractive to the grey fox in coming decades. Given the lack of information on habitat selection of Canadian grey foxes and the knowledge that grey foxes apparently thrive across much of the U.S., including areas that are highly developed (e.g. suburban areas), the effect of increased agricultural development is unknown. Finally, predation by coyotes and other top carnivores is not considered important to grey fox population dynamics, although there is some circumstantial evidence that coyotes have a negative impact on grey foxes. The original status designation suggested these factors in the absence of any information on numbers of grey foxes in Canada.

Available information on the abundance and distribution of the grey fox in Canada is fragmentary and inadequate to allow an estimation of population trends. There is also considerable uncertainty about the current number of grey foxes in Canada, making it difficult to assess the risk of extinction for this species.

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