Pair-bond formation and mate fidelity among juvenile Willow Tits

Abstract

Willow Tits Poecile montanus maintain yearlong defence of their territories, and outside the breeding season the territorial pair lives in a "winter flock" with one or two pairs of unrelated juveniles that have settled after post-natal dispersal. Although the pair formation of juveniles involves the process of winter flock formation, it has been suggested that pairing may occur before flock formation. Here I report on 5–6 week old juveniles that form pair-bonds 1–2 weeks after dispersal. This is the first description of mate choice and pair formation of Willow Tits before establishment in a winter flock.