The African migration and wintering grounds of the Aquatic Warbler Acrocephalus paludicola

There is a clear need for protection of the migration and wintering grounds of the Globally Threatened Aquatic Warbler Acrocephalus paludicola, but little is known about them and the threats they face. To narrow this gap, a desk study was performed between May 1998 and October 2004. Information on known wintering grounds was sought by means of questionnaires, personal communications, ringing data, publication and internet searches. Results show that the Aquatic Warbler has so far been recorded in nine African countries, but with recent records since 1980 from only five countries (Egypt, Ghana, Mauritania, Morocco and Senegal). All present data suggest that the Aquatic Warbler migrates through north-west Africa in autumn and spring, with the wintering grounds limited to wetlands of western sub-Saharan Africa, with verified records only from Mauritania, Mali, Senegal and Ghana during the months of August to April. The species was almost always found in habitats similar to that of its breeding grounds, i.e. in Carex, Juncus or Phragmites (sedge, rush and reed) associations, but also in dense grasses, shrubs and other vegetation found in freshwater marshes, flooded or wet meadows, and along the edges of backwaters, flood basins, lagoons, lakes, ponds, rivers and wadis. Recent research suggests that at least some Aquatic Warblers may actually winter further south than the present data suggest, in countries such as The Gambia, Guinea-Bissau, Guinea, Sierra Leone, Liberia, Ivory Coast, Ghana, Togo and Benin, or maybe even in so far unexplored wetlands in Central or East Africa. Because wetlands throughout Africa face imminent threats from agricultural and tourist development, more fieldwork is urgently needed to further pinpoint the migration and wintering grounds of the Aquatic Warbler.