Published online by Cambridge University Press: 11 May 2010
Twenty-eight predominantly tropical bird species have ranges that only just extend into the north-eastern part of South Africa, mainly within the Kruger National Park (KNP). These species are listed as “rare” (200 breeding pairs) in the South African Red Data Book (Brooke 1984). This study assesses the extent to which six of these rare bird species represent viable populations in the KNP. Grid squares in the KNP (2.5 × 2.5 miles) were visually assessed according to several bird habitat parameters. Bird records were also plotted on this grid system and habitat associations were identified for each species. This allowed for the measurement of total suitable habitat within the KNP for each species. Bird densities within known habitat were determined using spot-mapping and fixed-distance strip-transect techniques. Estimated population sizes for each species were obtained by extrapolating density estimates to total suitable habitat. Of the six study species, Arnot's Chat, Rudd's Apalis, Wattle-eyed Flycatcher and Tropical Boubou are likely to occur in sufficient numbers to constitute viable populations within the KNP, with estimated population sizes of 1,394, 4/758/ 2,070 and 10,450 birds respectively. The populations of White-crowned Plover and Long-tailed Starling are probably too small to be viable in the long term, with estimated population sizes of 305 and 382 birds respectively. The results presented here are testable and can be used as a baseline for future monitoring.