The anatomy of a failed reintroduction: a case study with the Brown Treecreeper

Abstract

Reintroductions are often used to re-establish a self-sustaining population of a species as a conservation method. Despite their prevalence, few reintroductions have followed recent international recommendations to publish details such as appropriate site-selection, criteria for success and experimental analyses of the reintroduction. Here we report on the first experimental reintroduction of the Brown Treecreeper (Climacteris picumnus), a ground-foraging Australian woodland passerine. Seven social groups (43 individuals) were released into two nature reserves in south-eastern Australia. Using a robust comparison of habitat-restoration treatments, we evaluate the influence of these treatments and demographic parameters of the Brown Treecreepers on measures of success of the reintroduction. Although individual Brown Treecreepers lost an average of 5.82% of their bodyweight during translocation, survival during the first 24 h and the first 3 days after reintroduction was high and was not significantly influenced by habitat treatments at the release site. There was, however, evidence of high levels of mortality in the first 2 months after release, but there was no influence of sex or age on apparent survival. These apparent losses may be attributable to longer-term effects of translocation stress, lack of familiarity with habitat or insufficient effectiveness of restoration treatments. Although this reintroduction appears to have failed, we present details on all aspects of the reintroduction to provide vital information and lessons learned regarding procedures and outcomes.