What happens to translocated game birds that ‘disappear’?

The ultimate goal of most translocation efforts is to create a self-sustaining wild population of a species deliberately moved from one part of their range to another. As follow-up of a translocation attempt is often difficult, causes for failure are relatively unknown. Dispersal away from the release site is one potential source of failure because it decreases the likelihood of the released population establishing itself post-translocation. In this study, we used chukar Alectoris chukar as a surrogate for translocated game birds in order to conduct a large-scale experimental study. We observed that these desert-adapted birds demonstrate a strong fidelity for specific water sources. We also report the propensity for the translocated individuals to either disperse and return to their original water source site or remain at the release site. During two field seasons, we observed opposing behaviors such that the proportion of individuals returning to the capture site, versus those remaining at the release site, shifted between years. We analyzed this change between the years as well as within the years to assess the potential underlying causes such as translocated distance, differences in rainfall between seasons and water source type. We concluded that homing behavior was strong in this non-migratory bird species and that strength of this homing behavior varied, potentially due to conditions surrounding the limiting resource, water availability. The large-scale, original data presented here may help to explain why some releases result in a successfully established population while other releases result in widely dispersed individuals.