Use ‘anti-predator training’ to improve survival after release
Overall effectiveness category Unknown effectiveness (limited evidence)
Number of studies: 2
Background information and definitions
If individuals have been raised in captivity, it is unlikely that they will have encountered predators and, in consequence, may have lost some of their innate fear leaving them vulnerable after release. Using predators under controlled conditions can therefore teach them to avoid dangerous species and potentially increase post-release survival.
Supporting evidence from individual studies
A review of a 1978-89 reintroduction programme for cheer pheasants Catreus wallichii in northern Pakistan (Garson et al. 1992) found that post-release survival was low between 1978 and 1985, with all 17 birds released in 1981 predated by foxes Vulpes vulpes. This was thought to be because birds nested on the ground and were relatively fearless due to rearing techniques. From 1982 onwards, birds were flushed into trees at dusk by workers in their release enclosures and appeared to survive better, with 10-15% of 305 birds released in 1986 and 1988-9 surviving for at least one year. This programme is discussed in more detail in ‘Release captive-bred individuals’.
A small trial in Saudi Arabia in 1995-7 (van Heezik et al. 1999) found that captive-bred houbara bustards Chlamydotis undulata macqueenii released at a desert site were significantly more likely to avoid predation if they were exposed to a live fox Vulpes vulpes in their cages before release, compared to control birds (raised without contact with predators) (44% of 18 predator-trained birds killed by predators vs. 83% of 18 controls). However, exposing birds to a model fox which ‘lunged’ at the birds had no impact on post-release survival (53% of 15 model-trained birds killed by predators vs. 36% of 11 controls). Survival of birds exposed to a live fox was also higher than for birds reared with puppets to minimise human contact (42% of 12 puppet-reared birds predated, see ‘Use puppets to increase the survival or growth of hand-reared chicks’ for details). Exposure to the fox consisted of introducing a hand-reared fox into the birds’ cage on a leash for between 40 seconds and 15 minutes (depending on how aggressive the fox was). There were 12 training sessions, with the fox muzzled for eight of them. Three birds were seriously injured during training, one of which later died (birds were then moved to larger cages and the fox more tightly muzzled which prevented any further injuries).Study and other actions tested