Seasonal changes in the structure of an avian community in an urban habitat in northern Namibia

Abstract

Two seasons of the year, dry and wet, are characteristic climate elements in southern Africa. Caused by differential precipitation, this seasonality induces seasonal variation in primary and secondary production. Birds are also affected. An avian community was studied in dry and wet seasons in an urbanised habitat of Tsumeb, a town situated in northern Namibia. Although both the species richness and the general dominance structure were similar in the dry and wet seasons, the avian community differed significantly in terms of population density of more common species in this town. Sörensen similarity index between the dry and wet seasons was low (I = 0.68). As expected, among granivorous species, the Laughing Dove (Streptopelia senegalensis), the Rosy-faced Parrot (Agapornis roseicollis), the House Sparrow (Passer domesticus), and the Southern Masked Weaver (Ploceus velatus) were much more numerous in the dry than in the wet season. However, contrary to expectation, the Blue Waxbill (Uraeginthus angolensis) was much more numerous in the wet than in the dry season. The Red-eyed Bulbul (Pycnonotus nigricans) was more common in the wet season, but other frugivorous species, the Red-faced Mousebird (Urocolius indicus), was more numerous in the dry than in the wet season.