The effect of pre-release captivity on post-release performance in reintroduced eastern bettongs Bettongia gaimardi

Hold translocated mammals in captivity before release

A randomised, controlled study in 2011–2014 in a woodland reserve in Australian Capital Territory, Australia (Batson et al. 2016) found that holding translocated eastern bettongs Bettongia gaimardi in captivity before release did not affect their body mass after release relative to animals released directly into the wild. Bettongs released after time in captivity were heavier at release (1.9 kg) than were those released immediately (1.7 kg) though subsequently there were no significant differences in body weight (see paper for details). In 2011–2012, thirty-two adult wild-born bettongs were captured in Tasmania and translocated to mainland Australia. Sixteen randomly selected individuals were immediately released into a fenced reserve, where invasive predators had been controlled. The remaining 16 were housed for 30 days in small enclosures (0.5-1.0 ha) before transfer to larger enclosures (2.6–9.4 ha). In total, they were held for 95–345 days before release. Bettongs were radio-tagged and were trapped and weighed periodically up to 18 months after release.

(Summarised by: Ricardo Rocha)