Drivers of scarcity in the globally threatened Taita Falcon Falco fasciinucha: competition and habitat quality in the eastern escarpment region of South Africa

Abstract

Summary The Taita Falcon Falco fasciinucha is known to occur and breed at only a few locations in eastern and southern Africa and is currently listed as globally “Vulnerable” and “Critically Endangered” in South Africa. An accurate estimation of its conservation status is however hampered by a lack of data and understanding of the species’ habitat requirements and competitive interactions with congeners. Our aim was to address some of these knowledge gaps. We conducted cliff-nesting raptor surveys across a substantial area of the Mpumalanga/Limpopo escarpment in north-eastern South Africa and modelled habitat suitability for nesting Taita Falcons in relation to the proximity of conspecifics and a community of five other sympatric cliff-nesting raptor species, and in relation to a suite of biotic and abiotic environmental variables. Results suggested the location of Taita Falcon nest sites was negatively associated with distance to the nearest pair of conspecifics and the nearest pair of Lanner Falcons Falco biarmicus, and positively associated with tracts of intact, unfragmented forest and woodland around the base of the cliffs. Our results indicated that Taita Falcon and Lanner Falcon appeared to be responding in opposite ways to a directional change in environmental conditions. This response appeared to be detrimental to Taita Falcon and beneficial to Lanner Falcon. Furthermore, the degradation and destruction of Afrotropical woodland and forest is a documented and ongoing reality, both locally and across much of the Taita Falcon’s global distribution. We argue that our findings are sufficient to justify uplisting Taita Falcon to globally “Endangered”.