|Scientific Name:||Vulpes velox|
|Species Authority:||(Say, 1823)|
|Red List Category & Criteria:||Least Concern ver 3.1|
|Assessor(s):||Moehrenschlager, A., Sovada, M. & Members of the IUCN SSC Canid Specialist Group - North America Regional Section|
|Reviewer(s):||Sillero-Zubiri, C. & Hoffmann, M. (Canid Red List Authority)|
The Swift Fox was extirpated from Canada by 1938; however, reintroduction releases since 1983 have established a small population in Alberta and Montana. The southern periphery of the range is still central New Mexico and north-western Texas. Current estimates for the United States suggest that Swift Foxes are located in 39–42% of their historic range. But in much of the distribution populations are fragmented.
Historically, the Swift Fox was considered an abundant predator of the prairies, but numbers were severely depleted by the late 1880s and early 1900s. Swift Fox populations began to recover over portions of their former range beginning in the 1950s. The current population does not meet any of the thresholds for the threatened categories, therefore the species is presently assessed as Least Concern.
|Range Description:||The Swift Fox is native to short-grass and mixed-grass prairies of the Great Plains in North America (Egoscue 1979). On the northern limit of its range, the Swift Foxes was present in the Canadian provinces of Alberta, Saskatchewan, and Manitoba. The southern species boundary was New Mexico and Texas in the United States. Historical records also exist for areas in Montana, Wyoming, North Dakota, South Dakota, Nebraska, Kansas, Colorado, and Oklahoma. Some historical range descriptions include Swift foxes in Minnesota and Iowa; however, there are no verified records of occurrence in either state (Sovada and Scheick 1999). Iowa has one fossil record and several unconfirmed accounts. Minnesota has no records and no account of any merit.|
|Range Map:||Click here to open the map viewer and explore range.|
Following Swift Fox extirpation from Canada by 1938 (Soper 1964), reintroduction releases since 1983 have established a small Swift Fox population in Alberta, Saskatchewan, and Montana which now constitutes the northern extent of the species' range (Moehrenschlager and Moehrenschlager 2001). The southern periphery of the range is still central New Mexico and north-western Texas, and, in terms of historic distribution, Swift Foxes are currently not found in Manitoba or North Dakota. Current estimates for the United States suggest that Swift Foxes are located in 39–42% of their historic range depending on conservative versus liberal estimates of historic range and the time span of records that are considered (Sovada and Scheick 1999). As such, the conservative estimate, based on the relative presence or absence of swift foxes in counties throughout individual states, is that Swift Foxes are distributed across 505,149 km² while the liberal estimate is 607,767 km² (Sovada and Scheick 1999). But in much of the distribution populations are fragmented.
Historically, the Swift Fox was considered an abundant predator of the prairies, but numbers were severely depleted by the late 1880s and early 1900s. In Canada, the last recorded specimen was collected in 1928 (Carbyn 1998) and a single sighting was made in 1938 (Soper 1964). Zumbaugh and Choate (1985) provided evidence that, in Kansas, Swift Foxes were extremely abundant in the mid-1800s, but became less abundant by the turn of the 20th century. The species was probably extirpated from Kansas by the 1940s (Black 1937; Cockrum 1952; Hall 1955; Sovada and Scheick 1999). There are similar reports of population declines from other states (see Sovada and Scheick 1999).
Swift Fox populations began to recover over portions of their former range beginning in the 1950s (Martin and Sternberg 1955; Glass 1956; Anderson and Nelson 1958; Andersen and Fleharty 1964; Kilgore 1969; Sharps 1977; Egoscue 1979; Hines 1980). In the core of their distribution, in Kansas, Colorado and the Oklahoma panhandle, and New Mexico, populations are considered stable whereas populations in Texas and Wyoming are fragmented and more vulnerable to decline. Swift Foxes are rare in Nebraska, South Dakota, and Montana, and extirpated from North Dakota (Allardyce and Sovada 2003).
Following approximately 50 years of extirpation, a Swift Fox reintroduction programme was initiated in Canada in 1983. By 1997, 942 foxes had been released, primarily utilizing captive breeding but also through the use of translocations (Moehrenschlager and Macdonald 2003). Using live trapping, a 1996/1997 census estimated the Canadian population to consist of 289 individuals in two isolated subpopulations. A second census that re-sampled these sites during the same season in 2000/2001 also expanded the survey area into Montana (Moehrenschlager and Moehrenschlager 2001, Moehrenschlager et al. 2004). The results showed that Swift Fox population size in Canada had increased three-fold since 1996/1997, the total known distribution including Montana spanned at least 17,500 km², the combined population size was approximately 877 individuals, and that 98.6% of the population is now wild-born. This population is considerably isolated from the contiguous Swift Fox range in the United States and needs to be considered separately in terms of population viability.
In the United States, Swift Fox populations are believed to be stable in Texas, New Mexico, Oklahoma, Colorado, and Kansas. The population in Wyoming is relatively stable but fragmented. Less is known about the population in Nebraska, but there appear to be four disjunct populations of unknown status. In South Dakota, populations are small and fragmented; some are considered stable. Swift Foxes are extinct in North Dakota. Reintroductions of Swift Foxes are being implemented at two sites in South Dakota. The Turner Endangered Species Fund began reintroducing foxes in 2002 in the Bad River Ranch south-west of Pierre. There are also plans for a reintroduction to The Badlands National Park in 2003. The Defenders of Wildlife are currently supporting (1998–present) a reintroduction in northern Montana's Blackfeet Reservation.
|Habitat and Ecology:||The Swift Fox is predominately found on short-grass and mixed-grass prairies in gently rolling or level terrain (Kilgore 1969; Hillman and Sharps 1978; Hines 1980). In Kansas, Swift Foxes have been found to den and forage in fallow cropland fields such as wheat (Jackson and Choate 2000; Sovada et al. 2003). Survival rates (and reproductive rates although sample sizes were small; Sovada et al. 2003) between foxes in grassland and cropland sites were not significantly different suggesting that Swift Foxes may be able to adapt to such habitat in some cases (Sovada et al. 1998). Notably, the distribution and density of dens, are considered important components of Swift Fox habitat requirements (Herrero et al. 1991), particularly in terms of evading coyote predation or Red Fox competition (Tannerfeldt et al. 2003).|
|Major Threat(s):||Since Swift Foxes are primarily prairie specialists, ongoing conversion of grassland to cropland threatens to reduce population sizes and further fragment populations. The conversion of native grassland prairies has been implicated as one of the most important factors for the contraction of the swift fox range (Hillman and Sharps 1978). We believe that alteration of the landscape likely influences local and seasonal prey availability, increases risk of predation on Swift Foxes, and leads to interspecific competition with other predators such as the Coyote and Red Fox. Moreover, an increasing trend towards irrigation of crops from the dry-land farming practices of fallow cropland every other year could exclude Swift Foxes that have adapted to den and forage successfully under the dryland farming rotational practices. The planting of tall, dense vegetation as a part of the United States Conservation Reserve Program, may also negatively impact swift foxes because they avoid these densely vegetated habitats. In Canada, the oil and gas industry is expanding dramatically and previously isolated prairie areas are now targeted for exploration. Associated road developments will potentially decrease the habitat carrying capacity and increase vehicle-caused Swift Fox mortalities. Greater urbanization coupled with coyote control may facilitate Red Fox expansion, which could lead to the competitive exclusion of Swift Foxes in established prairie areas. In the United States, the 1972 presidential ban on predator toxicant use (e.g., strychnine, compound 1080) on Federal lands may have contributed to Swift Fox recovery, but 1080 is currently being legalized in prairie areas of Saskatchewan, Canada, which will likely limit reintroduced populations. Moreover, landowners that are attempting to protect their livestock from Coyote depredation use poisons illegally and swift foxes readily consume such baits (Moehrenschlager 2000).|
Not listed on CITES Appendices. The Swift Fox has been down-listed from 'extirpated' to 'endangered' in Canada as a result of the Swift Fox reintroduction programme. In the United States, the Swift Fox was petitioned for listing under the Endangered Species Act. In 2001 the US Fish and Wildlife Service determined listing to be unwarranted.
In Canada, Swift Foxes are found mainly on unprotected lands, but approximately one-sixth of the population falls within the boundaries of Grasslands National Park. In the United States, there are 24 National Park Service Units (Parks, Monuments, Historic Sites) located in the historic range of Swift Foxes; however, there are no records of Swift Foxes in any of these units, yet 14 have potential for Swift Fox presence. One unit, Badlands National Park in South Dakota, is tentatively planning a reintroduction of Swift Foxes in 2003.
In Canada, the National Swift Fox Recovery Team is currently revising its national Swift Fox recovery strategy, which will be implemented through national and provincial action plans as of 2003. The Canadian federal government has just passed the country's first 'Species at Risk Act', which will provide greater legal protection of Swift Foxes and promote landowner stewardship programmes facilitating local conservation efforts. In the United States, the Swift Fox Conservation Team operates under a Swift Fox Conservation Strategy Plan with identified goals up to the year 2005. The team continues to monitor populations, assess critical habitat conditions, review the potential for reintroductions, and provide research support for ongoing projects.
In Canada, Swift Foxes are present in the Calgary Zoo, Cochrane Ecological Institute, Kamloops Wildlife Park, and Saskatoon Zoo. In the United States, Swift Foxes are represented in the Bismarck Zoo, Bramble Park Zoo, Houston Zoo, Lee Richardson Zoo, Living Desert, Minnesota Zoo, Philadelphia Zoo, Pueblo Zoo, Sunset Zoo, Tulsa Zoo, and Wild Canid Center. The Fort Worth Zoo has put forward a petition to manage a swift fox Species Survival Plan on behalf of the American Zoo Association. On behalf of the Canid Taxon Advisory Group, the St. Louis Zoo is currently devising recommendations for Swift Fox space allocations in the North American programme.
Gaps in knowledge
In Canada and the United States assessments of historical distribution and the identification of critical Swift Fox habitats for legal protection are hampered by the fact that Swift Fox habitat use is not well understood. Future studies should assess to what degree swift foxes can utilize differing types of habitats, including habitats considered atypical, such as those dominated by cropland. Information is needed to identify why Swift Foxes are unable to move into areas of apparently suitable habitat. Identification of barriers, both physical and ecological (e.g., competitive exclusion with other canids), to dispersal would improve the ability to manage and ultimately conserve this species. Future investigations should focus on parameters that might affect the range-wide, long-term viability of the populations.
The primary stochastic factor influencing small canid populations around the world is disease (Woodroffe et al. 1997; Laurenson et al. 1998; Woodroffe and Ginsberg 1999), and such risks are enhanced when animals are transferred between populations (Woodford and Rossiter 1994). Although the Canadian population was partly established through translocation, Swift Fox exposure to canid diseases has not been assessed in Canada. The prevalence of disease exposure in different age classes and regions should be assessed in both countries and the likelihood of disease transfer between Swift Foxes and sympatric Coyotes, Red Foxes, and domestic dogs should be evaluated. In addition, genetic analyses should be conducted to examine bottlenecks, genetic variability, connectivity, and dispersal distances in Canada and within isolated population fragments of the United States. Finally, data on Swift Fox demography, disease prevalence, genetics, habitat use, and population trends should be incorporated into Population Viability Models to guide conservation planning on a provincial/state or federal basis.
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|Citation:||Moehrenschlager, A., Sovada, M. & Members of the IUCN SSC Canid Specialist Group - North America Regional Section 2008. Vulpes velox. The IUCN Red List of Threatened Species. Version 2014.2. <www.iucnredlist.org>. Downloaded on 02 September 2014.|