Stress response assessment during translocation of captive breed Greater Rheas into the wild

LECHE A.; VERA CORTEZ M. ; DELLA COSTA N. S.; NAVARRO, J. L.; MARIN R. H.; MARTELLA M. B.

JOURNAL FUR ORNITHOLOGIE

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2016 vol. 157 p. 599 - 607

0021-8375

Translocation is an extensively used conservation tool that involves animals´ exposureto stressful situations that may influence the post release survival. In this study, 20Greater Rheas (Rhea americana) adults hatched and reared in captivity weretranslocated to a wildlife refuge. After transport and before release, animals were keptin pens at the liberation site to make a "soft-release" strategy. Fecal glucocorticoidmetabolites (FGM) were monitored during Pre-transportation, Post-transportation andPre-release, and Post-release phases as an indicator of the stress of translocation andacclimation to the new environment. During Pre transportation phase, FGM levelsfound were consistent with the baseline concentrations described for this species formales and females, respectively. On Day 1 after transportation, FGM levels wereincreased in both sexes returning to baseline values during the maintenance in thepens. Although the handling and transportation triggered an acute stress response, theprocedures utilized and the soft release in pens allowed rheas to quickly reestablishbaseline FGM levels. After release into the novel wildlife refuge, FGM levels wereincreased again and remained similarly increased during the following two month of thestudy. Findings suggest a strong chronic stress response, probably triggered by acombination of many factors (i.e. novelty, attacks from predators, social interactions,human related disturbances such as poaching, vehicular noise, hunting dogs) that mayreduce the bird´s ability to solve new challenging situations, especially the illegalhunting pressure that seems to be a significant threat in this species.