How do Different Releasing Techniques Affect the Survival of Reintroduced Grey Partridges Perdix perdix?

The quality of released individuals can have a significant impact on the success of reintroduction projects. We tested which of the following release techniques resulted in the highest survival of released grey partridges Perdix perdix in Switzerland : 1) translocation of wild adult birds, 2) release of captive parent-reared adults as family groups, and 3) fostering of captive parent-reared chicks to wild barren pairs. Wild hatched offspring (F1 birds) from our re-established breeding pairs served as the control group. We used a multi-state capture-recapture model to estimate monthly survival rates from the data based on monitoring of radio-tagged individuals and reobservation and recovery of ringed individuals. Survival tended to be highest in wild-hatched partridges of the founder population (mean±SE; 0.90±0.03), followed by that of fostered chicks (0.86±0.03) and translocated adult wild birds (0.82±0.06). While survival of these groups was not statistically different from each other, survival of captive-reared adults was significantly lower (0.70±0.06). We discuss the implication of our results for further partridge reintroduction projects.