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Swift Fox - Vulpes velox
Swift Fox - Vulpes velox

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Geographic Range
Swift foxes originally ranged from the plains of western Canada and across the Great Plains of North America to Texas. Swift foxes disappeared entirely from Canada in the 1930s, but have been reintroduced there. At present there are a few scattered populations of swift foxes in the Great Plains of the U.S. and in western Canada. The largest population is in Colorado, Kansas, New Mexico, and Wyoming, where the species is stable. There are currently approximately only 350 individuals located in Southeast Alberta and Southwest Saskatchewan.

Swift foxes live primarily in shortgrass prairies and deserts. They often form their dens in sandy soils on open prairies, along fences or in plowed fields.

Physical Description
Mass : 2 to 3 kg (4.4 to 6.6 lbs)
The swift fox is the smallest of the wild dogs in North America. Adults weigh between 2 and 3 kilograms and are approximately 30 cm tall and 80 cm long. They are about the size of a domestic cat. Males and females look similar except that males are slightly larger. The fur of V. velox is light grey with orange-tan coloring on the sides and legs. The throat, chest, underside and inside of the ears are creamy white. The tail is bushy and marked with black at the tip. There are also black patches on either side of the snout.

Breeding interval : Breeding occurs yearly. 
Breeding season : The breeding season begins from December through March. 
Number of offspring :2 to 6; avg. 4.25
Gestation period : 50 to 60 days
Time to weaning : 42 to 49 days
Time to independence :6 months (average)
Age at sexual or reproductive maturity (female) :2 years (average)
Age at sexual or reproductive maturity (male) : 1 years (average)

Individuals sometimes pair for life, but may not necessarily mate with the same partner each year.
Male swift foxes mature and mate at one year, while females may wait until their second year before breeding. The breeding season for individuals in Canada begins in March. The gestation period is 50-60 days and pups are born in mid-May. The breeding season for individuals farther south in the United States begins in late December, early January, with pups born in March and early April. Swift foxes have only one litter annually, with a litter size ranging anywhere from 2 to 6.
Pups are born in the underground den and typically remain there for about one month. After birth, the eyes and ears of the pups remain closed for 10 to 15 days, thus leaving them dependent on the mother for food and protection. Pups are weaned when 6 to 7 weeks old but usually remain with the mother and father until the fall.

Longest known lifespan in wild : 3 to 6 years
Longest known lifespan in captivity : 14 years (high)
Swift foxes usually live between 3 and 6 years in the wild, but may live up to 14 years in captivity.

The swift fox is indeed rather swift, reaching speeds of over 50 km/h. Their speed helps them catch food and avoid predators. Swift foxes also avoid predators by seeking shelter in burrows. Their dens are burrows underground, usually 2-4 meters in length with 4 entrances. Vulpes velox is mainly a nocturnal species. Daytime activities are confined to dens and vary seasonally. In winter, foxes may sun bathe during the warm midday period, while in summer they only spend early evenings and nighttime above ground.

Food Habits
The diet of the swift fox varies seasonally, depending on what is available. It typically eats whatever live prey it can catch. Its diet includes small mammals, birds, reptiles, amphibians, fish, insects, but also includes berries and grasses.

Economic Importance for Humans: Negative
The cost of captive breeding programs and monitoring after reintroduction can often be high.

Economic Importance for Humans: Positive
In the past, the fur of the swift fox was a valued commodity.

Conservation Status
IUCN Red List: Least concern; No special status.
US Federal List: Endangered.
CITES: No special status.
The swift fox is a severely endangered species. It has faced habitat losses due to agricultural, industrial and urban development. Hundreds of swift foxes were killed accidentally during the early 1930s from predator control programs aimed at removing wolves, coyotes, and ground squirrels from prairies. In 1978, the species was declared extirpated in Canada. There are currently populations of swift foxes in the U.S. ranging from South Dakota to Texas. However, the population is stable only in the central part of the range. Reintroduction programs in Western Canada have established small populations in southeast Alberta and southwest Saskatchewan, totaling 350 foxes. The current goal of reintroduction programs in Canada is to establish a viable, self-sustaining population distributed across the prairies and to remove the species from the endangered category by the year 2000.

Several things can be done to try to prevent further loss of and to encourage repopulation of swift foxes. Preserving the habitats of the foxes is crucial. Also, captive breeding could help increase the number of swift foxes. Reintroduction programs, like the ones in western Canada, may also be successful in restoring the swift fox to its natural habitat. However, a large number of reintroduced individuals do not survive their first year in the wild for one reason or another. Therefore, populations must be monitored and protected from human harm. Even though it is illegal to kill swift foxes, they are sometimes mistaken as coyotes and killed.

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Other Comments
There is ongoing controversy over whether swift foxes should be divided into two separate species, swift foxes (Vulpes velox) and kit foxes (Vulpes macrotis). Protein electrophoresis data and morphometric analyses have suggested that the species Vulpes velox contains both swift foxes (Vulpes velox velox) and kit foxes (Vulpes macrotis) (Ewer 1973; Clutton-Brock et al. 1976; Dragoo et al. 1990; Wozencraft 1993). However, other morphometric analyses (Stromberg and Boyce 1986) and analyses based on mitochondrial DNA (Mercure et al. 1993) have suggested that swift foxes and kit foxes are indeed distinct species. In fact, the study by Mercure et al. (1993) demostrated that swift foxes and kit foxes are as closely related to Arctic foxes (Vulpes lagopus) as they are to one another. In any case, swift foxes and kit foxes are ecologically and morphologically similar taxonomic groups. The former is distributed to the east of the Rocky Mountains, and the latter is distributed to the west. There is a narrow hybrid zone between the two populations in eastern New Mexico and western Texas (Mercure et al. 1993). (Clutton-Brock, Corbert, and Hills, 1976; Dragoo et al., 1990; Ewer, 1973; List and Cypher, 2004; Mercure et al., 1993; Moehrenschlager and Sovada, 2004; Stromberg and Boyce, 1986; Wozencraft, 1993)
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Additional Information - 

Population Numbers - 
Although historical population levels of Swift Fox are unknown, fur trading records give an indication of population size. The Hudson's Bay Company traded an average of 4,876 Swift Fox pelts annually between 1853 and 1877 (Rand 1948). The American Fur Company traded a total of 10,614 Swift Fox pelts between 1835 and 1838 (Johnson 1969). 

Brechtel et al. (1993) estimated the winter 1991-1992 Canadian Swift Fox population to be 225 foxes (range of 150-300) animals. Results of the 1996-1997 winter census suggest a population of 289 foxes in Canada (95 % confidence interval: 179 to 412 individuals; Cotterill 1997). 

Current estimates of the size of the Swift Fox population in the United States range from 16,400 to 27,500 animals (Kahn et al. 1996). Brechtel et al. (1996) estimated that the Canadian Swift Fox population represents less than one percent of the North American population. 

After suffering a drastic range-wide decline in the late 1800s and early 1900s, Swift Fox populations appear to be slowly increasing in Canada, primarily as the result of intensive reintroduction efforts. In the United States, increasing population levels are accompanying range expansion. 

Diet - 
Primarily nocturnal, Swift Foxes are opportunistic predators that consume a variety of prey including mammals, carrion, invertebrates (grasshoppers and beetles), vegetation and small birds (Carbyn et al. 1994, Hines and Case 1991, Sharps 1994, Uresk and Sharps 1986). Remains of fish, amphibians and reptiles have also been identified in Swift Fox scat (Cutter 1958b, Kilgore 1969). Analyses of scat collected in Alberta indicated that the mammalian component consisted primarily of small rodents (64.1 %), followed by ungulates (23.6 %; probably as carrion), lagomorphs (5.2 %) and ground squirrels (2.1 %; Reynolds et al. 1991). 

Territories - 
Swift Foxes do not appear to be territorial and home ranges may overlap in high-quality habitat (Carbyn et al. 1994, Hines et al. 1981). Preliminary analyses of home range data collected on 16 Swift Foxes in the Alberta/Saskatchewan border area indicate an average home range size of approximately 34.1 km2 (A. Moehrenschlager, pers. comm.). This estimate is similar in size to a 32.3 km2 average home range calculated for seven Swift Foxes in Nebraska (Hines and Case 1991), and home ranges of 20 to 30 km2 documented in Colorado (Rongstad et al. 1990). 

Population Structure - 
Swift Fox populations appear to have a balanced sex ratio, are generally dominated by the juvenile age class and are characterized by high annual mortality rates (FaunaWest 1991). Brechtel et al. (1993) estimated the minimum annual survival rates for wild-born Canadian foxes as 46 % for adults, and 36 % for juveniles during their first year. Annual survival rates of 56 % overall, 67 % for adults and yearlings and 38 % for pups were recorded in Colorado (Covell and Rongstad 1989). 

Predation was the principal cause of mortality and accounted for 58 % of known deaths for 89 of the Swift Foxes released between 1987 and 1991 on the Canadian prairies (Table 2; Carbyn et al. 1994). Coyotes (Canis latrans) are the main predators (Brechtel et al. 1993, Carbyn et al. 1994, Rongstad et al. 1989, Scott-Brown et al. 1986) and will often kill, but not consume the much smaller Swift Fox in what appears to be interspecific competition between the two species. Other predators include the Badger, Golden Eagle (Aquila chrysaetos) and Bobcat (Lynx rufus; Brechtel et al. 1993, Carbyn et al. 1994, Fitzgerald et al. 1983, Rongstad et al. 1989). Human-induced mortality, due to road kills, hunting or trapping, also occur to a lesser extent. 
Despite the high rate of annual mortality, Brechtel et al. (1996) estimated that an average litter size of 3.9 was sufficient to support slow growth of the Canadian Swift Fox population.

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Swift Success
Rare Foxes Return to Montana. 

As the hot August day faded to dusk on the Blackfeet nation in northern Montana, clouds with bellies full of lightning came thundering eastward off the Rocky Mountains. It promised to be a lively night here at the start of the Great Plains, especially with Dave Ausband waving a metal antenna around. He was trying to locate signals from radio-collared swift foxes. While the University of Montana graduate student homed in on one, his wife and research partner, Liz Ausband, swept a spotlight ahead across rolling hills of buffalo grass. The beam caught three sets of eyes bouncing over the prairie like disembodied green sparks: an adult male with two young kits. A larger set of eyes glowed close by: a badger, traditional enemy of the fox, looking back. 

At just four to seven pounds, fully grown swift foxes weigh less than house cats. Badgers tip the scales at 15 to 25 pounds and have a formidable set of teeth to go with their long claws. Despite these lopsided statistics, one of the kits edged closer, as if taunting its nemesis. Earlier in the year, the Ausbands saw a swift fox dash up and nip a badger on the nose. But maybe this young fox just wanted to see what prey might be flushed from the burrow where the bigger predator was digging. Before the Ausbands could find out, the kit lost interest and started to chase its father. With their long tails held straight behind like plumes, the foxes became streaks of fur and eyeshine playing across a boundless plain like the wind. 

Scenes like this, once common on the North American prairie, hadn’t been witnessed in Montana since the 1950s, when the last swift foxes disappeared from the state. In 1998, the Blackfeet tribe and Defenders of Wildlife started a joint project to reintroduce the species on the tribe’s 1.5-million-acre reservation. The Ausbands spent the past three years studying the reservation’s new residents and, according to Dave’s final report, released in December, the results all point to success.

"The swift fox population on the reservation is growing,” he concluded. "Not only have the Blackfeet tribe and Defenders of Wildlife reached their goal of restoring an extirpated species to tribal lands, they have also potentially initiated a comeback of swift fox along the Rocky Mountain Front in Montana.” 

The swift fox is North America’s smallest wild canine and also one of its fastest. It has to be. Active mainly at night, the fox must prove swift enough to catch hares, prairie dogs, ground squirrels, mice and voles before these creatures can disappear into burrows. At the same time, this lithe, little carnivore needs its top speed of nearly 40 miles per hour to outrace coyotes, bobcats, raptors and other predators—at least for long enough to reach the protection of its own underground dens. 

One threat the species named Vulpes velox (as in velocity) couldn’t outrun was the westward spread of settlement. Swift foxes once flourished throughout the short-grass and mixed-grass prairies, from Texas far into Canada. But trapping, poisoning and loss of native prey struck the carnivore community like a hurricane that wouldn’t leave. Then the prairies themselves began to vanish, replaced by plowed fields. By the 1930s, swift foxes were extinct in Canada and missing from most former range in the lower 48 states. They rebounded somewhat in the southern plains once poisons were better controlled but remained rare farther north, possibly because they no longer had carcasses from throngs of bison to scavenge during winter, when many rodents hibernate. 

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In the early 1980s, Canada began reintroducing swift foxes to southernmost Alberta and Saskatchewan. As Canada’s wild population grew toward its current total of more than 900, animals began colonizing an adjoining portion of north-central Montana. But they remained absent elsewhere in the northern prairie states, and nobody tried actively reintroducing swift foxes in the United States until 1998. That year, Defenders secured 30 from the Cochrane Ecological Institute, a private captive-breeding facility in Alberta, and with assistance from the tribe, released them onto the Blackfeet Reservation. Another 92 foxes were turned loose over the next four years. 

I accompanied biologists from the Blackfeet Tribal Fish and Wildlife Department on outings to capture, measure and place radio transmitters on foxes as part of the follow-up studies funded by Defenders. Each time we handled these canines, I wondered whether they weren’t actually part feline. When cornered in a live trap, they let loose ear-splitting screeches that would make an alley cat proud. Later, as I tracked a vixen through her range with Adrian Costel, a tribal researcher, he pointed out how swift foxes creep catlike through the grasses and wildflowers, almost on their bellies, until they are close enough to surprise prey with a lightning rush. The foxes will also leap high in the air like bobcats to snap at horned larks taking flight. I watched kits do the same to catch grasshoppers and moths. 

Another Blackfeet researcher, Spencer Momberg, told me, "Our elders remember the foxes being mostly around prairie dog towns. In the old days, those stretched 50 miles some places.” Once an abundant food for many grassland carnivores, prairie dogs have been shot and poisoned to the point of scarcity across most of the Great Plains. Fortunately, the reservation still produces ground squirrels in impressive numbers. This may partly explain why the survival rate of kits from spring to fall, when they begin to disperse from their parents’ home range, has averaged nearly 75 percent, higher than studies have typically found elsewhere. 

Dave Ausband pegs the reservation’s 2005 swift fox population at about 100. Though fewer than the total introduced, that number is considered encouraging, since small mammals released into unfamiliar territory typically suffer high losses from predators and other causes. "One hundred is only the number we actually observed,” Ausband added. "There could be twice that many out there.” When researchers distributed posters offering $100 to anyone who reported a previously undiscovered swift fox den with kits, the reward did more than generate new sightings. It helped raise awareness among tribal members that a long-missing resident had returned to the Blackfeet nation. 

The Blackfeet have always viewed this small but incredibly fleet prairie hunter as an equal in the great circle of life. "The tribe had a swift fox society with special songs and ceremonies,” said Momberg. He showed me a historical encampment called Ghost Ridge and described a deadly winter of disease and starvation after the tribe was first confined to the reservation. Although he never said so directly, I sensed that he and other Blackfeet feel a strong connection with species pressed to the brink of extinction—and with attempts to restore their vitality. 

In 2005, the Ausbands showed me a swift fox family living near the ranching town of Augusta, Montana, 55 miles south of the nearest previously known den and well beyond tribal lands. "Here’s proof that this isn’t just a reservation population any more,” Dave said as we fitted one of the kits with a radio collar. "It’s becoming a Rocky Mountain Front population.” Encouraged by the Blackfeet project, the Turner Endangered Species Fund reintroduced swift foxes to one of media mogul Ted Turner’s ranches in South Dakota during 2002. More were turned loose in Badlands National Park, South Dakota, the following year. And the Lower Brule Sioux are considering restoring the animals to their South Dakota lands. 

This is not to say that northern swift foxes are spreading like prairie wildfire. Far from it. They face many obstacles, including continued loss of native grasslands and competition from red foxes, which adapt better to agricultural areas. Canada no sooner upgraded the status of Vulpes velox from "extirpated” to "endangered” than the provinces of Alberta and Saskatchewan reinstated trapping and predator poisoning within recovery areas. Coyotes thrive despite persecution in many areas, and they rank as the leading cause of death for swift foxes. But this is largely because wolves, the foxes’ greatest ally, are missing and no longer fulfill their role of keeping coyotes in check. 

Saving wild creatures is often complex, expensive, time-consuming and controversial. Yet the Blackfeet swift fox project, undertaken on a tribal reservation with assistance from a nongovernmental group, shows how a comeback can speed right past bureaucracy and politics. 

"Think of all the uproar associated with the return of another canid—the wolf,” points out Minette Johnson, Defenders’ northern rockies representative. "Here, we re-established swift foxes in a short time with no controversy, and for about $30,000 a year. Not bad."

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