Population Densities and Community Structure of Birds Breeding in a Suburban Wooded Grassland in the Highveld of Lesotho

Abstract The mapping method was employed to study avian community structure in relation to rainfall in a town suburb in Highveld grassland in southern Africa. Studies were conducted in two breeding seasons: 1998, with dry spring; and 2001, with close to average spring rainfall. The total rainfall in 1998 was 1254 mm, while in 2001 it was 1445 mm, in both years much above the long-term annual average (866 mm). The avian community remained remarkably similar in both years, both in respect to the number of species (44 in 1998 and 53 in 2001), and dominance relationships. The Simpson’s Diversity Index was high and also very similar in 1998 and 2001 (D = 0.91; 0.93 respectively). In all years, dominant species included the Laughing Dove, Grey-headed Sparrow, Speckled Dove, Cape Turtle-Dove and Common Fiscal. The Southern Red Bishop in 2001 was also in the group of dominants. Significant differences were noted in the overall density of all birds, but contrary to expectation density was higher in 1998, with lower rainfall, than in 2001, with higher rainfall. The proportions of nesting and feeding guilds were similar in both years compared, except for the granivores, which were proportionally more common in 1998 than in 2001. This difference was mainly due to the Laughing Dove and Grey-headed Sparrow. Generally, it appears that the suburban avian community is more stable and more diverse than neighbouring communities in the natural habitats.