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COSEWIC assessment and update status report on the swift fox (Vulpes velox) in Canada (2000)

Population Size and Trends


In Alberta, swift foxes were released at 2 sites - the Alberta/ Saskatchewan border (including the Lost River Ranch area) and the Milk River Ridge area.  Due to problems with rabies, the latter site was abandoned soon after initial releases in 1989.

An intensive population census in 1996/97 resulted in the first detailed estimates of the overall success of the re-introduction program.  Numbers were obtained for the Alberta/Saskatchewan border area and for Grasslands National Park area.  In the border portion of its range there were approximately 192 animals (95% confidence interval 93-346).  This result was obtained from trapping along random transects placed through the core portion of suspected swift fox range (Cotterill, 1997a).  The apparent population had increased from the 1994 survey, when numbers were estimated between 100-135 foxes (Mamo 1994a).

Density and population estimates in the 1996/97 survey were influenced by the home range size used in the calculations.  Home range size were based on radio-tracking information obtained from 1-2 year periods.  Home range sizes in the 3-month census period are likely smaller, hence the population estimates are affected.  Numbers may have been underestimated as a result of poor weather conditions.  Finally, not all areas likely to have foxes were covered.  For example, foxes that dispersed from Canada to the United States are not included (Cotterill, 1997a).

Wild-born foxes in the 1997 surveys formed the greater proportion of the population.  The proportion of wild-born foxes to released foxes (both captive-born and wild-captured) during the 1996/97 census was greater (Cotterill 1997a) than in the studies carried out in 1990/91 (Carbyn et al., 1994) but less than in the census carried out by Mamo in 1994 (Mamo 1994c).  The large proportion of wild-born foxes, and presence of both older and juvenile wild-born, may be an indication that a self-sustaining population has been successfully established.

In addition to the core population within the Alberta range, several other areas (Figure 4) have been known to contain swift foxes.  These are in the Bow Island and Brooks areas.  One dispersal of about 200 km has been documented for a radio-collared fox; another swift fox (animal was not marked) had been trapped 250 km from the closest release site (CWS files).  Since it was an unmarked animal, nothing can be said about its origin.



Two areas (East Block/West Block) were chosen as release sites in central Saskatchewan.  The sites are approximately 60 km apart.  Distances from the Alberta/Saskatchewan border populations to Grasslands National Park, East Block and West Block, are approximately 248 and 185 km respectively.

The total number of foxes present in the Wood Mountain area in the 1996/97 winter survey, was about half of that along the Alberta/Saskatchewan Border (Cotterill 1997a).  Seven foxes were captured in the East Block and 1 fox in the West Block.  Number of foxes released in east/west blocks to 1996 were approximately 245 and 121 respectively (exact numbers not known).  The estimated population in the Wood Mountain area (Saskatchewan only; excluding Montana), was set at 87 animals (Cotterill 1997a).



Swift foxes were not released in Manitoba as prairies in that province are not extensive enough to warrant a reintroduction program.  It is questionable if the species ever existed in significant numbers in this area (Pattimore 1985).

One remarkable observation was made on 19 April, 1997 by Peter Sawatzky, resident of Glenboro, Manitoba.  On only that one day he and his son watched a swift fox at a den.  The den was in atypical swift fox habitat and on the edge of an agricultural field.  This would have been a questionable record, had the observer not been a naturalist, and had there not been quality photographic evidence available to verify the identity of the fox. 

There is some question as to how the swift fox reached that location.  Natural dispersal from the nearest known Canadian population would mean a dispersal distance of 700 or more kilometres.  Much of the intervening space is highly modified agricultural land and, to a lesser extent, wooded areas as well.  Although it is not known where the nearest U.S. population may have been, neither distance nor habitat suitability makes it likely that the fox had dispersed northward.  Major stretches of agricultural areas and incised riparian habitat intervened.  The closest record due south appears to be of a swift fox seen in 1990 in the Missouri Grasslands area in North Dakota, some 225 km from the Canadian Border. 


Population structure

Age/sex structure

Two sources of information provided data on population structure.  These are the 1996/97 winter survey (Cotterill 1997a) and studies by Moehrenschlager and Michie (1994-1998).  Population structure information gives an indication of the "robustness" of the reintroduction, trends and survivorship.

During the winter census, the ratio of young to adults was equal.  More males than females were caught (20 to 12).  The sex ratio amongst adults was even but more than twice as many juvenile male foxes were captured than females (11 to 5).  Of the 32 foxes captured 26 were wild-born, four were captive-reared and two were transplanted from Wyoming.  Eight wild-born foxes had been previously marked and of the 18 unmarked, 7 were adults and 11 juveniles (Cotterill 1997a).

In the Alberta/Saskatchewan border area a similar number of adults (13) and juveniles (11) were trapped and both adult and juvenile classes were characterized by an equal sex ratio (Cotterill 1997a).  In contrast, the Wood Mountain ratio was noticeably higher for males than females (7 to 1).

Trapping success

A calibration-based census technique was designed to circumvent logistical constraints associated with winter fox trapping.  The calibration-based method used current Canadian swift fox home range data to determine: 1) the area sampled by a series of six live-traps set one kilometre apart; and, 2) a trapping success correction factor based on the success of the census method in capturing marked swift foxes within known home ranges.  This correction factor was used to adjust and interpret trapping results throughout the census area. (Cotterill 1997a).

Fifty-eight townships were surveyed during the census, representing approximately 54% of the suspected core swift fox ranges in Canada.  Six box traps were each placed one kilometre apart along a trap line within each surveyed township.  Townships were surveyed for three nights (56), while two townships were censused for two nights, resulting in a sampling effort of 1,032 trap nights.  Winter weather conditions were exceptionally severe, yet the overall trapping success was encouraging.  Trapping success provided a measure of the occurrence and relative density of animal populations in different areas.  The overall trapping success was 4.9%[1].  If only new captures are considered the success rate was 3.1%.

Thirty-two individual foxes were trapped and a total of 51 captures, including recaptures, were recorded.  Trapping success was 4.9% per trap night, and 3.1% per trap night for one-time captures.  Four of 14 "calibration" foxes were trapped, resulting in a correction factor of 3.5.  Therefore, every fox captured represented 3.5 foxes in the area surveyed.

In the census, trapping success per sample block within a township ranged from 0 to 17% with a range of 0 to 3 foxes caught per trap line during a 3-night period.  Seventy five per cent of the foxes captured in the census were within 50 kilometres north, east and west of the Alberta/Saskatchewan/Montana border junction (Cotterill 1997a). 

The correction factor was also expressed in terms of 29% trapping success.  Ten non-calibration animals were also captured in the calibration townships (Cotterill 1997a). It was highly fortuitous that the above survey results were integrated with the research program carried out at the time by Axel/Cynthia Moehrenschlager and data collected by Jasper Michie and other field workers.


Legal protection

Now that the foxes have become established, a framework of protection is important.  Below is a summary of the 1998 regulations.[2]


The swift fox is identified in the Saskatchewan Wildlife Act, under the Wild Species at Risk Regulations as an endangered species (gazetted on 27 January 1999).  Specifically under Section 52 (1), part (V) of the Wildlife Act, 1997, it is given full protection on private, provincial and federal lands and it is forbidden to:

(a)        kill, injure, possess, disturb, take, capture, harvest, genetically manipulate or interfere with, or attempt to do any of those things to swift foxes.

(b)    export or cause to be exported from Saskatchewan any wild species at risk.

(c)     traffic in any wild species at risk.

Any person who contravenes clause 52(1) is guilty of an offence and liable on summary conviction.

In the case of an individual:

i)    for a first time offence to a fine ranging from not less than $10,000  to $100,000, to imprisonment for a period not exceeding two years, less a day, or both.

ii)   for a second or subsequent offence, to fines ranging from $20,000 to $200,000, to imprisonment.

In the case of a corporation:

i)    for a first offence, to fines ranging between $10,000 and $500,000.

ii)   for a second or subsequent offence, to fines ranging from $20,000 to $1,000,000.

Presently the intent of the legislation is not to prosecute landowners, or other individuals, who unknowingly destroy listed species on their habitat, but to raise awareness among landowners, resource users, the general public and government agencies on the identification and presence of listed species.

Section 5(1) of the Wild Species at Risk Regulations (1999) provides protection for swift fox dens.

Section 6(3) of the Wildlife Regulations (1981) provides additional protection, in that swift fox may not be killed by landowners or land occupants for the purpose of protecting property or livestock.


The swift fox is identified in Schedule 6 of the General Wildlife Regulation (AR 143/97) under the Wildlife Act as an Endangered Animal.  As an endangered animal it is given full protection.  This includes general prohibitions against hunting (meaning to shoot at, harass or worry, chase, pursue, capture or wilfully injure or kill or attempt to do so, etc.), trapping and trafficking (meaning to sell, buy, barter, solicit or trade or offer to do so).

Section 38(1) of the Wildlife Act (1984) states that  "A person shall not wilfully molest, disturb or destroy a house, nest or den of wildlife prescribed by the Minister in areas and at times prescribed by the Minister."  Section 96(a)(i) of the Wildlife  Regulation states that Section 38(1) of the Act applies to "endangered animals throughout Alberta throughout the year".

Section 10(1) of the Wildlife Act states that "Subject to this section, the property in all live wildlife in Alberta is vested in the Crown."  Section 10(3) goes on to indicate that  "... the property in wildlife that ceases to be held in captivity reverts to the Crown."

Section 11(1) states that "After the death in Alberta of wildlife belonging to the Crown, the property in it remains in the Crown unless the Minister transfers it to another person..."  Section 92(4) states that a person who is convicted of an offence of hunting or trafficking of an endangered animal  "...is liable to a fine of not more than $100,000, or to imprisonment for a term of not more than 6 months, or both."


The species is a furbearer solely under state authority.  This means, with a valid license, the species can be trapped.  Under state law, persons convicted of knowingly taking, possessing or transporting furbearers or pelts in violation of the rules or laws, shall be fined not less than $50 or more than $1000, imprisoned in the county jail for not more than 6 months, or both.  In addition, such person shall forfeit his privilege to hunt, fish or trap for not less than 24 months.  Civil restitution from $100 to $500 may be assessed for each illegal animal or pelt.

The swift fox is not presently a federally listed species under the United States Federal Endangered Species Act (ESA), so none of the laws or penalties associated with this federal Act would apply.  However, if the swift fox becomes a listed species under the ESA, two different scenarios could develop:

(1)  Accidental taking of an animal could be allowed if a special 4(d) rule is developed with the states without penalties. 

(2)  Without a special rule, that persons convicted of illegal take would be subject to fines up to $20,000 and/or 2 years in jail.


In summary, the swift fox is provided with legal protection in Alberta, Saskatchewan, to a lesser extent, Montana, and significant penalties may be levied for the hunting or trafficking of this species.  Despite legal protection, there are a significant number of cases of trapping (accidental catches), poisoning (intended for coyotes) and hunting (mistaken identification), to warrant concern.  Swift fox dens are also protected throughout Alberta and Saskatchewan.

[1]51/1,032 trapnights

[2]updated to 1999.