Diet of sympatrically breeding Southern Carmine Bee-eater Merops nubicoides and White-fronted Bee-eater Merops bullockoides

The Southern Carmine Bee-eater Merops nubicoides and White-fronted Bee-eater Merops bullockoides are insectivore, cavity-nesting bird species, both of which occur in the Zambezi Region, north-eastern Namibia. I examined there the diet composition of these species by an analysis of prey remnants. The Southern Carmine Bee-eater chick's diet consisted of exclusively insects, represented by seven orders. The most numerous were orthopterans and beetles (40.9% and 26.1%, respectively; n = 582 prey items). Hymenopterans (18.7%) and bugs (12.9%) supplemented the diet, whereas dragonflies (Odonata) and moths (Lepidoptera) were preyed only occasionally. In the diet of the White-fronted Bee-eater, nesting at the same site, beetles were the most important prey (81.2% of all 101 prey items identified), with scarabaeids comprising more than half of the beetle diet. In comparison with the White-fronted Bee-eater, a lower proportion of beetles, but much larger proportion of orthopterans were recorded in the diet of the Southern Carmine Bee-eater. In both bee-eater species, hymenopterans appear to be less important than was expected. The essential difference in the proportion of main prey groups recorded in Southern Carmine and White-fronted Bee-eaters breeding at the same site may represent a shift in food niche due to both temporal segregation in breeding, and differences in food preferences (feeding sites).