Habitat selection by whitethroats sylvia communis during spring passage in the sahel zone of northern nigeria

Minimum densities of Whitethroats Sylvia communis were estimated from 409 point counts at five sites in the Sahel zone of northern Nigeria during March?April 1995. Higher densities occurred in woodland than on farmland, open rangeland or semi-desert. Within woodland Whitethroats were seen more frequently in Balanites aegyptiaca than would be expected from its relative availability. Balanites aegyptiaca had the densest canopy and highest density of invertebrates, suggesting that the preference of Whitethroats for this tree may be because it offers the best protection from predators, heat and/or the best foraging opportunities. The presence or absence of Whitethroats within a point was, however, best predicted by high tree species diversity rather than foliage volume, canopy volume or tree density (though all of these factors were correlated). It seems likely, therefore, that diverse, relatively undegraded Sahelian woodland is a preferred habitat for Whitethroats during the spring migration period.