OVERLAP OF MOLT AND FALL MIGRATION OF THE WESTERN TANAGER AND WARBLING VIREO IN SOUTHERN CALIFORNIA

Abstract

 It is an axiom of ornithology that the energy-demanding phases of a small bird’s life cycle, such as molt and migration, are segregated temporally (e.g., Newton 2008). Ths principle applies so widely that exceptions to it may be instructive. Here we report apparent exceptions in two species, the Warbling Vireo (Vireo gilvus) and Western Tanager (Piranga ludoviciana), on the basis of recent specimens from southern California.