Shrub-Dwelling Birds in the Sahel Forage Less Often on the Ground in Grazed Areas

Abstract

Shrub-dwelling birds may resort to ground-foraging in the Sahel when opportunities are favourable. Several arboreal and semi-arboreal passerines, both African and European, were frequently recorded foraging on the ground, but not in heavily grazed areas. Grazed, dry savannah probably has fewer insects on the ground, which is often devoid of vegetation in the dry season. Shrub-dwelling birds foraged more frequently on the ground in the eastern Sahel, where grazing pressure is lower. In the Sahel grazing pressure increased fourfold since the 1960s, presumably reducing opportunities for arboreal bird species to facultatively forage on the ground. Due to increased grazing pressure, Common Whitethroats Curruca communis and other shrub-dwelling passerines may have lost a specific niche within their foraging habitat. This has compounded the greater losses associated with declines of woody vegetation during the drought years since the late 1960s.