Conservation Evidence strives to be as useful to conservationists as possible. Please take our survey to help the team improve our resource.

Providing evidence to improve practice

Individual study: Release method evaluation for swift fox reintroduction at Bad River Ranches in South Dakota

Published source details

Sasmal I., Honness K., Bly K., McCaffery M., Kunkel K., Jenks J.A. & Phillips M. (2015) Release method evaluation for swift fox reintroduction at Bad River Ranches in South Dakota. Restoration Ecology, 23, 491-498


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 study in 2002–2007 on prairie in South Dakota, USA (Sasmal et al. 2015) found that post-release survival rates of captive-bred swift fox Vulpes velox pups were lower than survival rates of wild-born pups. The proportion of captive-bred pups that survived for 60 days after release (48%) was lower than the proportion of wild-born pups that survived for 60 days (100%). Forty-three pups (26 male, 17 female) born in pens to wild-caught foxes formed the captive-bred cohort. They were released in mid-July of 2003–2007. Survival was compared, using radio-telemetry and visual observations at dens, to that of 90 pups born in the wild in 2003–2007, to previously translocated and released foxes.

(Summarised by Nick Littlewood)

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

A controlled study in 2002–2007 on a large area of prairie in South Dakota, USA (Sasmal et al. 2015) found that using holding pens at release sites affected survival rates of translocated swift foxes Vulpes velox. A higher proportion of foxes released after 14–21 days in holding pens survived for ≥60 days post-release (76%) than of foxes held in pens for >250 days (66%) or released after 14–21 days in kennels at a field station (61%). A total of 179 foxes (85 males and 94 females; 91 adults and 88 sub-adults) were translocated in 2002–2007. Holding pens provided acclimatisation at release sites, with food provided at pens following release. Foxes released from short stays in holding pens, and those released having been held in kennels, were released in August–October. Long-stay foxes were released in mid-July. Survival was monitored by radio-tracking and visual observations at dens.

(Summarised by Nick Littlewood)