Winter microhabitat distribution of coots (Fulica atra L.1758) on gravel-pit wetlands in the Garonne river floodplain, Southwest France

Human population growth, urbanisation and conversion of land to agriculture have led to loss of natural wetlands throughout the World, making artificial wetlands such as gravel pits, dam lakes or rice fields important for waterbirds. In south-west France, the increasing abundance of gravel pits has allowed several bird species to colonize the region. These ``new'' wetlands have become substitutes for the natural habitats of waterbirds. Coots (Fulica atra L. 1758) colonised the Midi-Pyrenees area when gravel pits were created in the 1970's. Coot populations were censused weekly from October 1996 to February 1997 and from October 1997 to February 1998 on three gravel pits near Toulouse, SW France. Each winter, the number of coots was recorded on each gravel pit, and the microhabitat used by coots identified according to environmental variables (water depth, bank slope, bank vegetation, vegetation between watermarks, macrophytes, human disturbance, zones of open water or near the bank). Open water, which constitutes a secure habitat for this species during the wintering period, abundance of macrophytes (Characea) and presence of lawn on the bank appear as the most important factors influencing coot distribution. This information will be useful for site acquisition for nature conservation and management purposes.