Annual molt cycle of arctic warbler (Phylloscopus borealis) from northwestern siberia and its geographic variation

摘要

The arctic warbler, which nests in the Polar Urals and in northwestern Siberia, has one full molt in wintering areas in the first year of life; over the next years, two molts: partial postnuptial in the nest area and complete prenuptial in the wintering part of the area. The molt in the first year of life, according to the photoperiodic response to the increasing day, is prenuptial. There may be a geographical population of Arctic warblers with a postjuvenile molt of minimum completeness in Central Siberia.