Maximising success: Translocation does not negatively impact stress reactivity and development in petrel chicks

Abstract The order Procellariiformes, or albatross and petrels, face declining populations and many species hold threatened species status. Translocations of petrel chicks are increasingly recognised as a powerful conservation tool with multiple benefits: restoring species to their former range, restoring lost land-sea ecological linkages and ‘spreading the risk’ for threatened species. However, translocations are stressful events for chicks. Petrel chicks are able to perceive and respond to stressors from hatching at a level comparable to adults. Consequently, if chronic stress is induced in petrel chicks by translocation, it may result in energy divergence away from growth and condition, with potentially ongoing negative effects throughout the birds' lives. The aim of this research was to define how translocation impacts stress reactivity and development in petrel chicks and to use this information to guide best-practice for petrel translocations. Mottled petrels ( Pterodroma inexpectata ) are a target for major translocation-restoration programmes across New Zealand. We measured total corticosterone from mottled petrel chicks at regular intervals coinciding with key translocation events from two groups: one that underwent translocation according to current best practice (Translocation group), and a group that remained in the natal colony (Control group). Growth, weight and fledging parameters of the Translocation group were compared against a multi-year source colony average. We found there was no difference in stress reactivity between Translocation and Control chicks, or development between Translocation and chicks at the source colony. Petrel translocation practitioners may proceed in the knowledge that current practices did not induce a state of chronic stress or alter stress reactivity in mottled petrel chicks, and therefore are unlikely to negatively impact post-fledging survival, and their capacity to establish viable colonies. However, we caution that these results may not apply to other petrel species with different life-history strategies to mottled petrels, and encourage testing in a wider range of species.