By Mike Henry
Abstract Since the 1990s the status of the Pallid Harrier Circus macrourus in western Europe has changed beyond all recognition. Once an extremely rare vagrant, it now appears increasingly regularly in several countries. Since 2003, a few pairs have bred in Finland in most years although numbers are influenced by vole population cycles. On migration, high numbers of juveniles usually follow good vole years, and the development of a northeast–southwest migration across Europe is discussed. Reports of birds wintering in southern and central Europe are increasingly frequent. A lack of data from the species’ core breeding range in European Russia and central Asia is hampering a better understanding of population changes.
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