A critical evaluation of the role played by the red-billed oxpecker Buphagus erythrorhynchus in the biological control of ticks

Abstract

Buphagus erythrorhynchus uses 4 feeding methods-scissoring, plucking, pecking and insect catching. During the day the birds spend 68% of their time feeding, with peaks of activity during the early morning and late afternoon. A total of 21 641 ixodid ticks were found in 53 stomachs examined, with a range of between 16 and 1 665 per stomach. Boophilus and Rhipicephalus were the most important genera eaten. Thirty Diptera, also found in the stomachs, accounted for 0,4% of the diet by mass. The food of the nestlings consisted of 45,6% ticks, 19, 4% Diptera and 35,0% hair and tissues. When kept in captivity, Buphagus was able to account for an appreciable reduction in the numbers of Boophilus on cattle, reaching a figure of 95,7% reduction for adult ticks. In controlled experiments Buphagus showed the highest preference for Boophilus decoloratus, Rhipicephalus appendiculatus and Hyalomma truncatum. The daily food intake of a captive bird was 14,7 g, which is equivalent to 7 195 engorged Amblyomma hebraeum larvae. Three acaricides, namely, amitraz, chloromethiuron and DDT, did not cause any clinically detectable toxicity in captive birds during a 5-day period.