Habitat selection by Whitethroats Sylvia communis during spring passage inthe Sahel zone of northern Nigeria

Minimum densities of Whitethroats Sylvia communis were estimated from 409 p oint counts at five sites in the Sahel zone of northern Nigeria during Marc h-April 1995. Higher densities occurred in woodland than on farmland, open rangeland or semi-desert. Within woodland Whitethroats were seen more frequ ently in Balanites aegyptiaca than would be expected from its relative avai lability. Balanites aegyptiaca had the densest canopy and highest density o f invertebrates, suggesting that the preference of Whitethroats for this tr ee may be because if offers the best protection from predators, heat and/or the best foraging opportunities. The presence or absence of Whitethroats w ithin a point was, however, best predicted by high tree species diversity r ather than foliage volume, canopy volume or free density (though all of the se factors were correlated). If seems likely, therefore, that diverse, rela tively undegraded Sahelian woodland is a preferred habitat for Whitethroats during the spring migration period.