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Providing evidence to improve practice

Individual study: Landscape features influence postrelease predation on endangered black-footed ferrets

Published source details

Poessel S.A., Breck S.W., Biggins D.E., Livieri T.M., Crooks K.R. & Angeloni L. (2011) Landscape features influence postrelease predation on endangered black-footed ferrets. Journal of Mammalogy, 92, 732-741


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 mammals into fenced areas Terrestrial Mammal Conservation

A replicated study in 1996–1997 in three grassland sites in South Dakota, USA (Poessel et al. 2011) found that at least half of captive-bred black-footed ferrets Mustela nigripes released into fenced areas where predators were managed survived more than two weeks. At each of the three sites, 48% (12 of 25), 50% (9 of 18) and 89% (32 of 36) of captive-bred ferrets released into the wild survived for at least two weeks (long-term survival is not reported). Overall, twenty-four ferrets were killed by native predators (mostly great-horned owls Bubo virginianus and coyotes Canis latrans) and the cause of death of two others could not be determined. A total of 79 captive-bred black-footed ferrets were released across three mixed-grass prairie sites (18–36 ferrets/site) in September–October 1996 and October–November 1997. A 107 cm high electric fence was installed in each release site (creating 2 km2 enclosures) and activated 1-2 weeks prior to ferrets being released. Ferrets were able to move in and out of the fenced areas. Low-to-moderate lethal coyote control took place for 2-3 weeks each year prior to ferrets being released. Each of the 79 ferrets was radio-tagged and tracked every 5–30 min/night for two weeks post-release in 1996–1997.

(Summarised by Ricardo Rocha)

Release translocated/captive-bred mammals in areas with invasive/problematic species eradication/control Terrestrial Mammal Conservation

A replicated study in 1996–1997 in three grassland sites in South Dakota, USA (Poessel et al. 2011) found that at least half of captive-bred black-footed ferrets Mustela nigripes released into an area where predators were managed survived more than two weeks. At each of the three sites, 48% (12 of 25), 50% (9 of 18) and 89% (32 of 36) of captive-bred ferrets released into the wild survived for at least two weeks (long term survival is not reported). Overall, twenty-four ferrets were killed by native predators (mostly great-horned owls Bubo virginianus and coyotes Canis latrans) and the cause of death of two others could not be determined. A total of 79 captive-bred black-footed ferrets were released across three mixed-grass prairie sites (18–36 ferrets/site) in September–October 1996 and October–November 1997. Low-to-moderate lethal coyote control took place for 2-3 weeks each year prior to ferrets being released. A 107 cm high electric fencing was installed in each release site (creating 2 km2 enclosures) and activated 1-2 weeks prior to ferrets being released. Ferrets were able to move in and out of the fenced areas. Each of the 79 ferrets was radio-tagged and tracked every 5–30 min/night for two weeks post-release in 1996–1997.

(Summarised by Ricardo Rocha)

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

A replicated study in 1996–1997 in three grassland sites in South Dakota, USA (Poessel et al. 2011) found that over half of released captive-bred black-footed ferrets Mustela nigripes survived more than two weeks. At each of the three sites, 48% (12 of 25), 50% (9 of 18) and 89% (32 of 36) of captive-bred ferrets released into the wild survived for at least two weeks (long term survival is not reported). Overall, 53 out of 79 captive-bred black-footed ferrets (67%) survived more than two weeks after release into the wild. Twenty-four ferrets were killed by native predators (mostly great-horned owls Bubo virginianus and coyotes Canis latrans) and the cause of death of two others could not be determined. A total of 79 captive-bred black-footed ferrets were released across three mixed-grass prairie sites (18–36 ferrets/site) in September–October 1996 and October–November 1997. Between 18 and 35 individuals were released at each site. Each of the 79 ferrets was radio-tagged and tracked every 5–30 min/night for two weeks post-release in 1996–1997.

(Summarised by Ricardo Rocha)