Defining moults in migratory birds: a sequence‐based approach

Two broad nomenclatures have emerged to describe moult strategies in birds, the ‘life‐cycle' system which describes moults relative to present‐day breeding and other life‐history events, and the Humphrey–Parkes (H–P) system which reflects the evolution of moults along ancestral lineages. Using either system, challenges have arisen defining strategies in migratory species with more than one moult per year. When all or part of two moults occur in non‐breeding areas, extra moults may fail to be recognized or they may have been discriminated temporally, whether feathers are replaced in fall, winter or spring. But in some cases feather replacement can span the non‐breeding period, and this has resulted in an…