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Providing evidence to improve practice

Individual study: Translocation of the endangered San Joaquin kit fox, Vulpes macrotis mutica: A retrospective assessment

Published source details

Scrivner J.H., O'Farrell T.P., Hammer K. & Cypher B.L. (2016) Translocation of the endangered San Joaquin kit fox, Vulpes macrotis mutica: A retrospective assessment. Western North American Naturalist, 76, 90-100


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

Release translocated/captive-bred mammals in family/social groups Terrestrial Mammal Conservation

A controlled, before-and-after study in 1989–1992 on a hilly grassland and scrubland site in California, USA (Scrivner et al. 2016) found that the survival of translocated San Joaquin kit foxes Vulpes macrotis mutica kept in pairs in holding pens prior to release was lower than that of resident animals. The survival of 40 translocated foxes in the first year after release (six alive, 32 dead, two unknown) was lower than that of 26 resident foxes (13 alive, 13 died), but did not change with the length of time spent in holding pens. Eleven pups born in the holding pens and released with their parents all died within 17 days of release. Only four foxes were known to breed after release, all with resident foxes. At the end of the study (1992) one fox was known to be alive and 36 (out of 40) were known to have died. Causes of death were predation (20 foxes), road accidents (two foxes) and death during trapping operations (one fox). The cause of death was unknown for 13 foxes. In August and December 1988 and January 1989, and from June–October 1989, foxes were caught and translocated up to 50 km to a 19,120-ha reserve. Foxes were kept in male–female pairs in holding pens (6.1 × 3.1–6.1 × 1.8 m) for 32–354 days before release in spring and summer 1990 (12 adults, 1 pup) and 1991 (28 adults, 10 pups). Foxes were monitored by radio-tracking 4–5 days/week after release.

(Summarised by Nick Littlewood)

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

A controlled, before-and-after study in 1989–1992 on a hilly grassland and scrubland site in California, USA (Scrivner et al. 2016) found that the survival of translocated San Joaquin kit foxes Vulpes macrotis mutica kept in holding pens in pairs prior to release was lower than that of resident animals, but did not change with the length of time in holding pens. The survival of 40 translocated foxes in the first year after release (six alive, 32 dead, two unknown) was lower than that of 26 resident foxes (13 alive, 13 dead), but did not change with the length of time spent in holding pens. Eleven pups born in the holding pens and released with their parents all died within 17 days of release. Only four foxes were known to breed after release, all with resident foxes. At the end of the study (in 1992) one fox was known to be alive and 36 (out of 40) were known to have died. Causes of death were predation (20 foxes), road accidents (two foxes) and death during trapping operations (one fox). The cause of death was unknown for 13 foxes. In August and December 1988 and January 1989, and from June–October 1989, foxes were caught and translocated up to 50 km to a 19,120-ha reserve. Foxes were kept in male–female pairs in holding pens (6.1 × 3.1–6.1 × 1.8 m) for 32–354 days before release in spring and summer 1990 (12 adults, 1 pup) and 1991 (28 adults, 10 pups). Foxes were monitored by radio-tracking 4–5 days/week after release.

(Summarised by Nick Littlewood)