Low survival after release into the wild : assessing the burden of captivity on Mallard physiology and behaviour.
“Captive-reared animals used in reinforcement programs are generally less likely to survive than wild conspecifics. The Mallard is a species with high adaptability to its environment and in which massive reinforcement programs are carried out. We studied physiological and behavioural factors potentially affecting body condition and survival of captive-reared Mallards after being released. Digestive system morphology and an index of body condition were compared among three groups: captive-reared birds remaining in a farm (control), captive-reared birds released into the wild as juveniles (released) and wild-born birds (wild). We also compared behaviour and diet of released VS wild Mallards. Finally, we conducted a 1-year survival analysis of captive-reared birds after release in a hunting-free area.
We argue that the low survival of released Mallards likely has a physiological rather than a behavioural (foraging) origin. In any case, extremely few released birds live long enough to potentially enter the breeding population, even without hunting. In the context of massive releases presently carried out for hunting purposes, our study indicates a low likelihood for genetic introgression by captive-reared birds into the wild population.”
Auteurs du document :
CHAMPAGNON J., GUILLEMAIN M., ELMBERG J., MASSEZ G., CAVALLO F., GAUTHIER-CLERC M.