The importance of roosts for Black Storks Ciconia nigra wintering in West Africa
Résumé
Seasonal variations in the use of roosts by Black Storks Ciconia nigra in West Africa were studied by satellite tracking and field observations between 1998 and 2006. Black Storks used twelve tree species as nocturnal roost. All roosting trees were higher than the surrounding vegetation (11.4 ± 3.9 vs. 4.2 ± 0.1 m). Black storks selected dead trees in 46% of the cases and showed a preference for roosts located close to foraging areas (on average within 4 km), the distance varying significantly according to season. On average, Black Storks used roosts for four consecutive days, alternating between roosts up to 41 times per winter period. Destruction of roosting trees could impact the birds' spatial distribution.