Food of the Little Swift Apus affinis and African Black Swift Apus barbatus in South Africa

Abstract

The food habits of the Little Swift Apus affinis and African Black Swift Apus barbatus were quantified at Kimberley, Northern Cape province and Makapansgat, Limpopo province, South Africa. As previously documented for other species, both of these swifts took a wide variety of aerial arthropods including spiders as well as 10 orders and 64 families of insects in the combined samples. Little Swift prey items at Kimberley averaged 3.2 mm in body length (SD = 1.6, n = 2 178) and ranged from 1.2 to 16.0 mm. Prey items of African Black Swifts at Kimberley averaged 4.4 mm (SD = 4.1, n = 185) with a range of 0.9 to 15.9 mm, and 2.8 mm (SD = 0.8, n = 2 099) at Makapansgat with a range of 1.2 to 10.8 mm. At Kimberley, African Black Swifts took more (8.3%) larger prey items (>8 mm), such as termites, than Little Swifts (2.3%). As also true of other swifts, both African Black Swifts and Little Swifts took a majority (>90%) of smaller prey items that are abundant in the air column. Mean prey size is significantly correlated with predator body size in Apus and Tachymarptis swifts.