The Biology of the Orangebreasted Waxbill

Summary Colahan, B. D. 1982. The biology of the Orangebreasted Waxbill. Ostrich 539–30 A general biological study of the Orangebreasted Waxbill Sporaeginthus subflavus, with an emphasis on breeding biology, was conducted in Hypharrenia grassland near Salisbury, Zimbabwe, mainly in 1973 and 1974. It is primarily a bird of open grassland and vleis and is found mainly above 1 000 m in Zimbabwe. Mensural data are presented, and seasonal variation in the weights of adults examined. General behaviour and habits are described and 13 different calls identified. Small, dry grass seeds picked off the ground make up the bulk of the diet, but small insects, green grass seeds and shoots are also taken. Moult appears to be prolonged and remex moultMaypossibly take as long as 7 months. Breeding has been recorded from December to July in Zimbabwe, but over 75% of records are for March and April, coinciding with the transition from the wet to the dry season. The species is monogamous and a small territory around the nest is defended against conspecifics. A closed grass nestMaybe constructed in matted grass or a small bush, but more commonly the vacated nest of another grassland bird is adopted and a soft lining added. Nest and nest site inspection are described. Nest building and/or lining is by the male only. The eggs are described and measurements from 211 given. Clutch size was 4–6 eggs, with a mean of 4,7. Incubation appears to begin with the laying of the second or third egg, is by both sexes and lasts about 13 days. The young are attended by both parents. They are fed mainly on small, dry grass seed, supplemented with small insects, especially during the fist few days. The nestling period is between 17 and 19 days, and the young remain with the adults for at least two weeks after this. Excluding breeding attempts which failed during laying, there was a 62% hatch; 30% of the young surviving the hatch were reared; and overall 18% of the eggs laid yielded flying young. This low figureMaynot be representative, because of human activities in the study areas. One species of feather louse, one species of feather mite, and two species of parasitic flies were collected from nestlings and nests. Of the adults and juveniles examined, only one juvenile yielded any ectoparasites, a hippoboscid fly.