Are parent-reared red-legged partridges (Alectoris rufa) better candidates for re-establishment purposes?

Abstract

Aiming to produce game birds suitable for re-establishment purposes, we studied the survival and behavior of 31 adult red-legged partridges reared by their natural parents in captivity (parent-reared) and 67 wild red-legs (35 adults and 32 subadults). Birds were radio-tracked and released in a game estate where management targeting small game species was conducted and shooting was not allowed. Survival of parent-reared partridges was shorter (mean 108 d) than wild adults (mean 160 d), though no significant differences were found. Parent-reared birds showed a longer escape reaction (mean 11.7 sec) than wild adults (mean 0.4 sec) and were mainly predated by terrestrial predators (52%), whereas the most important source of predation in wild red-legs was raptors (49%). The home range of parent-reared (mean 23 ha) was not significantly lower than wild adults (mean 27 ha). Nineteen percent of parent-reared and 31.4% of wild adults paired successfully, and we recorded 6 pairs in which one bird was wild and the other parent-reared and one pair in which both birds were parent-reared. A small proportion of red-legs started incubation (parent-reared 12.9%, wild 20%), and the proportion completing incubation was similar among wild and parent-reared birds. Overall, parent-reared red-legs showed similar survival and behavior compared to wild red-legs and better than intensively reared, so parent-reared red-legs should be chosen for the re-establishment of wild populations.