ABSTRACT
The hen harrier (Circus cyaneus) is a partial migrant, being entirely migratory in Northern, Eastern Europe and Asia, and resident, partial or short-distance migrant in Western Europe. Its wintering grounds are located in Europe, North Africa and in a relatively narrow band between Turkey and Japan. This species regularly hunts during migration, moving on a broad front singly or in very small loose flocks, mostly using the flapping flight. As a result, few birds are detected at raptor migration watchsites. During post-breeding migration, the highest counts have been reported on the Vistula Spit, along the southern coast of the Baltic Sea (Poland), and also slightly lower at Falsterbo, in Southern Sweden. Adults were seen migrating earlier than juveniles, probably under the pressure to get good winter territories. Ring recoveries of Scandinavian birds revealed that they move SSW to reach their wintering grounds mostly located in Central-Western Europe. Few British birds winter in mainland Europe, but some individuals tracked by satellite reached Northern Spain undertaking long water-crossings through the Bay of Biscay. Very few birds cross the Mediterranean to overwinter in North Africa. During pre-breeding movements counts of the same magnitude of those of Falsterbo were reported at Skagen (Denmark). In this period, males migrate earlier than females, probably to acquire the best nesting territories.
