Moult in the river warbler locustella fluviatilis

Abstract

Observations on River Warblers Locustella fluyiatilis caught on passage in Kenya have helped to identify some unusual moult features in this species. Adult and first year birds have a complete moult during January-March in winter quarters in southeast Africa, renewing their primaries in the typical passerine sequence. Adults also have an extensive autumn body moult, usually delayed until arrival in a stopover area in northeast Africa. In addition, practically all adults have a partial wing moult in northeast Africa during September-November. This involves the outermost one to five pairs of large primaries, which are therefore replaced twice each year. The outermost new autumn primaries appear to complete growth before the innermost. © 1983 Taylor & Francis Group, LLC.