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Providing evidence to improve practice

Individual study: The swift fox reintroduction program in Canada from 1983 to 1992

Published source details

Carbyn L.N., Armbruster H.J. & Mamo C. (1994) The swift fox reintroduction program in Canada from 1983 to 1992. Pages 247-271 in: M.L. Bowles & C.J. Whelan (eds.) Restoration of endangered species: conceptual issues, planning and implementation. Cambridge University Press, Cambridge, UK.


This study is summarised as evidence for the intervention(s) shown on the right. The icon shows which synopsis it is relevant to.

Release captive-bred individuals to re-establish or boost populations in native range Terrestrial Mammal Conservation

A replicated, controlled study in 1990–1992 at two grassland sites in Alberta, Canada (Carbyn et al. 1994) found that captive-born swift foxes Vulpes velox had lower post-release survival rates than did translocated, wild-born animals. No statistical analyses were performed. Nine months after release into the wild, at least two out of 27 (7%) captive-born swift foxes were known to be alive, compared with twelve out of 28 (43%) wild-born translocated swift foxes. In May 1990 and 1991, a total of 27 captive-born and 28 wild-born swift foxes were released simultaneously. Wild-born animals had been captured in Wyoming, USA, 4–7 months before release and were quarantined for ≥30 days. Animals were released without prior conditioning in holding pens. Foxes were radio-collared and monitored from the ground and air, for at least nine months.

(Summarised by Ricardo Rocha)

Release translocated/captive-bred mammals at a specific time (e.g. season, day/night) Terrestrial Mammal Conservation

A replicated, controlled study in 1987–1991 in three grassland sites in Alberta, Canada (Carbyn et al. 1994) found that, after one year, survival of captive-bred swift foxes Vulpes velox released in autumn was greater than that of captive-bred swift foxes released in spring. No statistical analyses were performed. At least 10 out of 71 (14%) swift foxes released in autumn survived over one year post-release, compared with at least one out of 27 (4%) of those released in spring. Eighty-one captive-born swift foxes were released in autumn and 41 were released in spring. They were provided with supplementary food for 1–8 months. Swift foxes were radio-collared and 98 were monitored from the ground and air for over one year.

(Summarised by Ricardo Rocha)

Hold translocated mammals in captivity before release Terrestrial Mammal Conservation

A replicated, controlled study in 1990-1992 at two grassland sites in Alberta, Canada (Carbyn et al. 1994) found that translocated swift foxes Vulpes velox that had been held in captivity prior to release had higher post-release survival rates than did released captive-bred animals. No statistical analyses were performed. Nine months after release into the wild, 12 out of 28 (43%) wild-born translocated swift foxes were known to be alive, compared with at least two out of 27 (7%) captive-bred swift foxes. In May 1990 and 1991, a total of 28 wild-born and 27 captive-bred swift foxes were released simultaneously. Wild-born animals had been captured in Wyoming, USA, 4-7 months before release and were quarantined for 30 days. Animals were released without prior conditioning in holding pens. Foxes were radio-collared and monitored from the ground and air, for at least nine months.

(Summarised by Ricardo Rocha)

Use holding pens at release site prior to release of captive-bred mammals Terrestrial Mammal Conservation

A replicated, controlled study in 1983–1993 in three grassland sites in Alberta, Canada (Carbyn et al. 1994) found that captive-bred and translocated swift foxes Vulpes velox released after time in holding pens had similar survival rates to those released without use of holding pens two years after release. No statistical analyses were performed. At least six out of 45 (13%) swift foxes held in pens before release survived over two years post-release, compared with at least five out of 43 (12%) released without use of holding pens. In 1983–1987, forty-five translocated swift foxes were held in pens before release. Pens (3.7 × 7.3 m) were fenced for protection from cattle. Animals were placed in pens in October–November and released between the following spring and fall. They were provided with supplementary food for 1–8 months after release. In 1987–1991, four hundred and thirty-three foxes were released without use of holding pens. Released foxes included both wild-born and captive-bred animals. All foxes released from pens and 155 of those released directly were radio-tracked, from the ground or air, for up to two years.

(Summarised by Ricardo Rocha)

Use holding pens at release site prior to release of translocated mammals Terrestrial Mammal Conservation

A replicated, controlled study in 1983–1993 in three grassland sites in Alberta, Canada (Carbyn et al. 1994) found that translocated and captive-bred swift foxes Vulpes velox released after time in holding pens had similar survival rates to those released without use of holding pens. No statistical analyses were performed. At least six out of 45 (13%) swift foxes held in pens before release survived over two years post-release, compared with at least five out of 43 (12%) released without use of holding pens. In 1983–1987, forty-five translocated swift foxes were held in pens before release. Pens (3.7 × 7.3 m) were fenced for protection from cattle. Animals were placed in pens in October–November and released between the following spring and autumn. They were provided with supplementary food for 1–8 months after release. In 1987–1991, four hundred and thirty-three foxes were released without use of holding pens. Released foxes included both wild-born and captive-bred animals. All foxes released from pens and 155 of those released directly were radio-tracked, from the ground or air, for up to two years.

(Summarised by Ricardo Rocha)

Translocate to re-establish or boost populations in native range Terrestrial Mammal Conservation

A replicated, controlled study in 1990–1992 at two grassland sites in Alberta, Canada (Carbyn et al. 1994) found that translocated, wild-born swift foxes Vulpes velox had higher post-release survival rates than did released captive-born animals. No statistical analyses were performed. Nine months after release into the wild, 12 out of 28 (43%) wild-born translocated swift foxes were known to be alive, compared with at least two out of 27 (7%) released captive-born swift foxes. In May 1990 and 1991, a total of 27 captive-born and 28 wild-born swift foxes were released simultaneously. Wild-born animals had been captured in Wyoming, USA, 4–7 months before release and were quarantined for ≥30 days. Animals were released without prior conditioning in holding pens. Foxes were radio-collared and monitored from the ground and air, for at least nine months.

(Summarised by Ricardo Rocha)