Feeding a Foreign Chick: a Case of a Mixed Brood of Two Tit Species

摘要

We report on a mixed brood of Great (Parus major) and Varied (Poecile varius) tits. The brood consisted of one Great Tit and five Varied Tits. Incubation and food provisioning to nestlings were by adult Varied Tits, but not by adult Great Tits. The foreign Great Tit nestling tended to receive more food than the average Varied Tit nestling. Provisioning of the foreign Great Tit by Varied Tits lasted even after fledging. We discuss the causes and outcomes of this rare phenomenon.