Social learning of food preferences by white-tailed ptarmigan chicks

The social-learning function of a food call is to share information about resources with conspecifics. Field studies on the social learning of food and parent-offspring interactions regarding food in a natural environment are rare. Our aims in a 2-year study in the Rocky Mountain National Park, U.S.A., were to monitor white-tailed ptarmigan, Lagopus leucurus, hens' food calls, a vocalizing and tidbitting display, to determine whether the hens selected foraging areas based on food availability and whether chicks learned about important food resources from hen food calls. Our findings indicate that the white-tailed ptarmigan hen's food call is a form of cultural transmission in which information regarding available food is disseminated from hens to chicks. Hens chose foraging patches where certain plant species were abundant and called their chicks to these foods, which dominated their diet. Chick consumption mirrored the calling rates of hens and as a result chicks ate high-protein foods, which are critical for chick growth and development. The results suggest that white-tailed ptarmigan hens' food calls may function to enhance survival of juvenile ptarmigan.