Space and habitat use by Red Kites Milvus milvus during winter in the Guadalquivir marshes: a comparison between resident and wintering populations

Differences in habitat selection, diet and behaviour of resident and wintering Red Kites Milvus milvus were studied in Donana National Park, southwest Spain. Adult resident Red Kites roosted at their nests, while immature residents and wintering birds gathered at communal roosts. Individuals remained on average for two consecutive nights (range 1–8) at the same communal roost. Wintering kites spent significantly more time foraging gregariously than residents. The use of the marsh was greater by wintering kites while residents more often used the forest. Wintering birds consumed more goose carrion than the residents. Wintering kites had larger core areas, moved farther from their roost sites to feed and changed foraging areas more frequently than residents. Among residents, adult females had the smallest home ranges (core area, distances travelled and time spent flying). We suggest that Red Kites wintering in Donana occupy the marsh because it provides high food availability, and is vacated by Black Kites M. migrans which exploit this profitable habitat during the breeding season.