The Diet of Nestling Rainbow Bee-Eaters, Merops-Ornatus, on Rottnest Island, Western-Australia, and Observations on a Non-Destructive Method of Diet Analysis

Abstract

The diet of nestling rainbow bee-eaters, Merops ornatus, was determined by analysis of droppings and regurgitated pellets collected at one site on Rottnest I., W.A. in the summer of 1982/83, and five sites in the summer of 1983/84. In total, 2187 insects from 10 families were identified. These comprised: Hymenoptera (95%), including Scoliidae (14%), Tiphiidae (38%), Sphecidae (l8.5%), Apoidea (1%), Formicoidea (7.5%) and undetermined Hymenoptera (16%); Coleoptera, Buprestidae (1.5%); Diptera, Muscidae (<1%); Hemiptera (3%); Odonata (<1%); and Orthoptera (<1%). The relative proportions of the different prey types varied significantly between sites and between different sampling times at the same site. There were also site-related differences in the mean length of nestling prey and at three sites nestlings were fed different sizes of prep during their development. Estimates of prey length based on wing remains were significantly smaller than those based on head remains at four of the six sites, and shapes of prey length distributions based on wings and heads were significantly different at all six sites.