Nesting distribution of vultures in relation to land use in Swaziland
Three species of vulture (African White-backed, White-headed and Lappet-faced) breed in Swaziland, all of which are threatened within the country. Vulture nests were surveyed using a fix-winged aircraft in low-lying savannas of Swaziland. Nesting was observed in three land use categories: (1) unprotected government cattle ranches, (2) protected cattle ranches, and (3) conservation areas. A total of 248 nests was recorded, of which 240 belonged to the African White-backed Vulture. Nesting densities were highest in conservation areas, an order of magnitude lower on protected cattle ranches and negligible on government ranches. Nests of White-headed Vultures and Lappet-faced Vultures were exclusively located in conservation areas. Nesting densities of African White-backed Vultures in some conservation areas exceeded 260 nests/100 km2, which are the highest known densities of this species anywhere in Africa. Nests were almost exclusively located in riparian vegetation, but at Hlane National Park a large proportion of nests were placed in open woodland, possibly as a result of an influx of vultures from adjoining agricultural lands that have only been transformed in recent decades. Where elephants were present in conservation areas, vultures did not nest within their enclosures. The location and density of vulture nests may possibly be used as an indicator of pressure on biological resources in low-lying savannas of Swaziland.