Comparing post-release survival and habitat use by captive-bred Cabot’s Tragopan (Tragopan caboti) in an experimental test of soft-release reintroduction strategies

Abstract

Background: Restoring a viable population by reintroduction is the ultimate goal of a large number of ex situ conservation projects for endangered animals. However, many reintroductions fail to establish a population in the wild, partly because released animals cannot acclimate to the native environment of the release site, resulting in very low survival rates. Acclimation training is a technique to resolve this problem, although it does not have positive results in all species. We tested whether acclimation training and soft-release could improve the reintroduction success for captive-bred Cabot's Tragopan (Tragopan caboti), an endangered pheasant in southern China. Methods: Reintroduction of captive-bred Cabot's Tragopan was carried out in the Taoyuandong National Nature Reserve, China from 2010 to 2011. We built a soft-release enclosure for acclimation training in the typical montane habitat of this pheasant. Nine birds were acclimated to the environment of this release site in this cage for more than 50 days before release ("trained birds"), while 11 birds remained only in the cage for 3 days prior to release ("untrained birds"). Released birds were tagged with a collar radio-transmitter. Results: Post-release monitoring revealed that the survival rate of trained birds was higher than that of untrained birds after 50 days (trained: 85.7%; untrained: 20.0%). Cox regression analysis showed that there was a significant difference in the mortality rates between the trained and untrained birds. In addition, a survey of the habitat of the experimental and the control groups showed significant differences in habitat selection between the groups. Conclusion: Our study suggests that pre-release acclimatization training is an important factor that can lead to improved survival and habitat selection of captive-bred reintroduced tragopans.

Preparing captive-bred birds for reintroduction: the case of the Vietnam Pheasant Lophura edwardsi

“…instant) releases (Condon et al 2019). The fact that some birds were found in or seen heading toward dense vegetation (as mentioned above), when matched with the finding in Liu et al (2016) that soft-released birds selected more appropriate habitat, strongly implies that establishing the release site amidst dense cover is likely to help releasees in terms of stress minimisation and survival capacity. Armstrong and Wittmer (2011) emphasised that 'the quality of the release site is a particularly important factor affecting the benefits gained from large releases.'…”

“…The duration of acclimatisation within the soft-release enclosure positively influenced postrelease survival of Red-billed Curassows, and a period of at least 47 days was consequently recommended (Bernardo et al 2011). Nine Cabot's Tragopans Tragopan caboti kept for over 50 days in a soft-release enclosure in the species's montane habitat survived far better than 11 birds held there for only three days (86% vs 20% after 50 days), and they selected habitats more typical of wild birds (Liu et al 2016). In Grey Partridges 'longer acclimatisation time at the release site was related to lower levels of corticosterone [associated with passive and therefore sociable behaviour] and partly enhanced survival after release' (Homberger 2014).…”

Captive Breeding and Reintroduction of Black Francolin, Grey Francolin and Chukar Partridge (2015-2020) in District Dir Lower, Khyber Pakhtunkhwa, Pakistan

“…It is also essential to acquaint the release experts with pre-release training so as to improve selection of species habitat and survival of captive-bred. (Liu et al, 2016) The partridges captive breed support wild population. Sport hunting shows direct and indirect effects on the conservation of wildlife species (Ericsson et al, 2004).…”

Post‐release dispersal and breeding site suitability of reintroduced populations of the Crested Ibis in Shaanxi Province, China

“…The quality of breeding sites exerts a significant impact on breeding success and survival rate (Cody 1985). Therefore, it is often believed that the breeding/nesting site plays an extremely important role in the life history of birds (Greene & Stamps 2001; Liu et al 2016).…”