Investigating the impact of large carcass feeding on the behavior of captive Andean condors (Vultur gryphus) and its perception by zoo visitors.

Naturalistic feeding methods, such as the provision of whole carcasses to zoo animals, are potentially controversial because zoo visitors might not approve of them. However, since several species of zoo animals feed from large carcasses in the wild, this food type could benefit their welfare in captivity compared to other less-natural food types. Scavengers in particular almost exclusively live on carcasses in nature; therefore, their welfare in captivity could significantly depend on the opportunity to express behaviors related to carcass feeding. In this study, we assessed the frequency of carcass feeding for vultures in North American zoos and investigated the effect of different food types on the behavior of zoo-housed Andean condors (Vultur gryphus). We also evaluated the opinion of North American zoo visitors about carcass feeding. Our results show that small whole carcasses (rats, rabbits) are part of the diet of vultures in most North American zoos, but large whole carcasses (ungulates) are rarely fed. Our behavioral study indicated that Andean condors appear to be more motivated to feed on more natural food types, which also seem to physically engage the birds more and occupy them longer. Most zoo visitors approved of carcass feeding for captive vultures over a range of prey animals, and the majority would also like to observe the vultures eat. Collectively, our results demonstrate that carcass feeding, particularly with larger prey, potentially enriches both zoo-housed vultures as well as the visitor experience.