Grey fox (Urocyon cinereogenteus) COSEWIC assessment and update update status report: chapter 2

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Grey fox
Urocyon cinereoargenteus

Species information

The grey fox, Urocyon cinereoargenteus, is similar to the red fox, but with a number of unique characteristics. Most noticeably, the grey fox’s fur is a grizzled grey colour, with cinnamon-coloured regions on its neck, sides and legs. There is a prominent black stripe running the length of the back down to the tip of the tail, which is also black, unlike the red fox’s, which is white. The grey fox’s prints closely resemble those of a domestic cat, but claws show in the fox’s print.


Distribution

The grey fox is generally found from southern Canada to northern Colombia and Venezuela. Archeological evidence suggests that the grey fox was almost as common as the red fox in southern Ontario as far north as Midland just prior to European occupation. Currently, the grey fox is thought to be present in two regions in Canada, the Rainy River District of Ontario (west of Lake Superior) into southern Manitoba, and in southeastern Ontario. Note to readers:The range of the Grey Fox in Manitoba is restricted to the southeastern corner of the province, where it appears to be accidental.


Habitat

The grey fox’s distribution is closely associated with deciduous forest, and in Canada it is also thought to inhabit marshland. Grey foxes den in many different kinds of substrate, usually located in dense brush close to a water source. In spite of these habitat preferences, U. cinereoargenteus is considered a habitat generalist and is quite tolerant of human disturbance. It is often found on the outskirts of cities.


Biology

U. cinereoargenteus is the most omnivorous of the North American canids. Vegetable matter, such as fruit, is an important year-round diet component. The grey fox has been observed to breed in Canada. The breeding season varies across their range, but Canadian grey foxes are thought to breed from mid-February to mid-March like populations in the northeastern U.S. Most female grey foxes breed in their first year and have one litter of about 3 or 4 kits per year. Grey foxes are typically nocturnal or crepuscular. The basic social unit consists of an adult male and female and their offspring, and this group maintains a home range that is largely exclusive of other such groups. The adult sex ratio is usually 1:1 and grey foxes are generally assumed to be monogamous. It is unclear whether grey foxes are territorial, but they apparently use urine and faeces in communication.


Population sizes and trends

Although no quantitative population-level study of the grey fox in Canada has ever been published, it seems highly likely that the number of mature individuals present in Canada is fewer than 250.


Limiting factors and threats

The most important factor limiting grey fox populations in the U.S. is harvesting by humans, but the effect of the apparent weak harvest pressure in Canada on grey foxes is unknown. It is likely that grey foxes are able to avoid close competition with canids such as coyotes and red foxes since they are often found in sympatry. Diseases such as canine distemper and rabies could become significant limiting factors in an epizootic situation. Climate is another factor, which may be important to long-term trends in grey fox populations. Other factors, such as deforestation and road mortality may have adverse effects on grey fox populations in Canada.


Special significance of the species

The low rate of capture (i.e. under 20 per year in Ontario) indicates that the grey fox has little economic value as a furbearer in Canada. This species is of great interest to naturalists and scientists alike because the reasons for its substantial range decline in Canada compared to pre-European times are unclear.


Existing protection or other status designations

The Nature Conservancy has ranked the grey fox globally as very common (G5); however, no national (N) rank exists for Canada. In Ontario and Manitoba the provincial conservation data centres consider grey foxes found in their provinces to be migrants from the United States. It is illegal to kill grey foxes in Quebec. The grey fox is thought to be present, although rare, in St. Lawrence Islands National Park, it has been found in Fish Point Provincial Nature Reserve, Pelee Island, and it is thought to be present in the Whiteshell Provincial Park region in southeastern Manitoba.

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