Black Vulture Nesting, Behavior, and Growth

Black Vultures (Coragypsa tratus) have nestedf or 5 consecutivey r (1975-1979) on a small island in Gatun Lake, Panamir. The 1975 nest site (McHargue 1977) was 6 m from nests of the following 3 yr, which were all within 1 m of each other. The 1979 nest site was 35 m distant, in the same location as that used by a pair of Turkey Vultures (Cathartes aura) in 1975 (McHargue 1977). Two eggs were laid about 13 December 1975 (estimated from the known fledging date of young), 28 October-6 November 1976, 16 November 1977, 12-18 November 1978, and about 10 October 1979 (estimated from development of young). Ranges represent the time between the day I last searched the area for eggs and the day eggs were found. Two young hatched and fledged in 1975 and 1976. In 1977 and 1978 only one young hatched; one of the 1977 eggs broke between 16 and 18 December, 6-8 days before the other egg hatched, and one of the 1978 eggs disappeared between 15 and 22 December, 4-12 days beforeh atching.T he 1977y oungf ledged,b ut the 1978y oungd isappearedw hen 4-8 dayso ld. Two young hatched in 1979 and were both present when 40 days old, after which time I could no longer observe them

LAURIE A. MCHARGUE, The Auk 98