Population densities and community structure of birds in riverine forest in the lowveld of Swaziland

Abstract

Population density and community structure of birds were studied at three sites in riverine forest in the lowveld of Swaziland. Birds were surveyed monthly using a standard point count technique. A total of 101 species of birds was recorded. Species richness at the three sites ranged between 70–76 species. Population density was similar at the three sites and ranged between 24.0–31.2 birds ha^-1. Biomass of birds was also similar at the three sites. Resident birds accounted for 74% of all species, but made up 97% of the individuals and biomass. There was a relatively large number of vagrant species, but they only accounted for <1% of the individuals and biomass. Species richness of intra-African and Palaearctic migrants was low, and they contributed little to total bird density or biomass. In terms of diet, the majority of birds were insectivorous, followed by the mixed diet category. Frugivores, though few in number, contributed significantly to biomass. Granivorous species and raptors contributed insignificantly. The avifauna of riverine forest in Swaziland is compared with similar habitats in southern Africa and with that of Acacia savanna and broadleaved woodland in Swaziland.



(Ostrich: 2003 74(3&4): 173–180)