Recent studies have shown that captive breeding projects will be key to the survival of some bird species over the next 200 years, prompting researchers from George Mason University, Virginia, to investigate which techniques are key in a successful reintroduction project.
After pouring over 1,074 papers and articles, Jessica Roberts, a doctoral student at George Mason, and biology professor Dr David Luther picked out 91 avian translocation projects from the last 50 years and covering 15 taxonomic orders to help identify best practices for the conservation tool.
Exposure to conspecifics has been used to maintain natural behaviour in captive-bred California Condors before release (Alexander Viduetsky).
The projects analysed were chosen because they all had first-year survival data. The data revealed that exposing birds to wild food before release, a behaviour-based technique, was crucial.
Dr Luther said: "Threatened and endangered species bred in zoos aren't really prepared to go live in a wild circumstance with predators and forage for their own food. Everything's given to them and they are protected."
Other behavioural-based techiniques were identified as having been benefical to some species. Captive-bred California Condors were exposed to adults of their own species in order to encourage more natural behaviour before release, while Puerto Rican Amazons have been taught to recognise predators before release.
They also found that successful projects initially released birds into a protected area within the species' natural habitat. A period of acclimatisation to the release site and the provision of supplemental food resources after release were also identified as important factors in bird reintroduction projects.
Roberts said that the consideration of behaviour-based management is relatively new in the wildlife conservation toolkit and emphasised that this means a broad look at its implications is important before further research on a more precise scale.
She said: "I've worked in captive breeding and rearing endangered species and saw that a lot of the time when we released them back to the wild, we did not understand the mechanisms behind why some individuals were thriving and others perished. The main goal of this research was to look for answers to these survival questions."
Roberts, who is due to graduate with her PhD in Environmental Science and Public Policy this May, hopes that the work will help inform future reintroduction and translocation projects, ultimately saving species from extinction in the decades and centuries to come.
Roberts, J L, & Luther, D. 2023. An exploratory analysis of behavior-based and other management techniques to improve avian conservation translocations. Biological Conservation. DOI: https://doi.org/10.1016/j.biocon.2023.109941