Temporal and Spatial Dietary Variation of Amur Falcons (Falco amurensis) in their South African Nonbreeding Range

We studied the spatial and temporal dietary patterns of the Amur Falcon (Falco amurensis), a nonbreeding Palearctic migrant to South Africa, by collecting regurgitated pellets at two large colonial roost sites, i.e., Middelburg and Newcastle, over 11 equal sampling periods during December 2012 to March 2013. We dried the pellets to constant mass and classified the prey items to the lowest taxonomic level possible. Amur Falcons fed mainly on invertebrates (seven orders), and occasionally on vertebrates (three orders). The five most abundant prey taxa (pooled for both sites) were; Coleoptera, Orthoptera, Isoptera, Solifugae, and Hymenoptera. Lepidoptera, Hemiptera, Passeriformes, Rodentia, and Soricomorpha were consumed almost 20 times less frequently. Isoptera, Hymenoptera, Lepidoptera, and Rodentia were consumed significantly more frequently at Middelburg, while Orthoptera and Solifugae were consumed more frequently at Newcastle. The consumption of Coleoptera did not differ significantly between sites but decreased through the season, being most important when falcons arrived in South Africa in December. Consumption of Orthoptera increased through the season and was greatest prior to migration. The percentages of Isoptera and Hymenoptera in the diet peaked at different periods, likely the result of prey population irruptions. Diet similarity of sample periods between sites ranged from 33.3-100% (mean = 69.5%), and within-site similarity among sample periods ranged from 50-100% (mean = 75.6%) and 37.5-100% (mean = 65.9%) for Newcastle and Middelburg, respectively. This study highlights the variable importance of specific prey taxa, predominantly invertebrates, for Amur Falcons during the overwintering period in South Africa.