BREEDING BIOLOGY OF THE BEARDED VULTURE IN SOUTHERN AFRICA, PART I: THE PRELAYING AND INCUBATION PERIODS

Abstract

Summary Brown, C. J. 1990. Breeding biolo of the Bearded Vulture in southern Africa, Part I: The pre-laying and incubation periods. Ostrich 61: 24–32. In southern Africa the Bearded Vulture Gpaetus barbatus lays its eggs in mid-winter. between the second half of May and the first week of July. Pairs became more active in their nesting areas about six weeks before laying and usually roosted there at night. Courtship flights were less frequent and demonstrative than in Eurasian birds and took place mainly in the late afternoons. During the pre-laying period most nest visits (77%) were to bring nesting material, 92% by the male. All nesting material was arranged by the female. Copulation was always preceded by allopreening, and occurred most frequently in the mornings. No copulation or courtship display took place after the first egg had been laid. Of 18 clutches, 16 (89%) contained two eggs and the remainder one egg. The laying interval was usually 3–5 days (range 2–9 days). Incubation started with the firs...