BEARDED VULTURE POPULATION AND HABITAT VIABILITY ...

Population and Habitat Viability Assessment: Bearded Vulture (Gypaetus barbatus)
________________________________________________
6. Life history
Breeding: Presumably monogamous in southern Africa, and solitary (Mundy et al. 1992: 213-
215). Polyandrous trios have been recorded in Europe (Heredia and Donázar 1990) as well as
solitary behaviour. In southern Africa three adults have been seen, on occasions, at the nests
on Monks Cowl and Black Mountain in 2004 (S. Krüger pers. comm.) and at the Black
Mountain nest in 2005 (S. Krüger pers. comm.; S.E. Piper, pers. obs.), though it is not known
if these trios were made up of one female and two males. Average inter-pair distance = 6.3 km
and min = 0.7 km in the high Drakensberg, 15 km in the Lesotho highlands and 19 km in the
northern Eastern Cape Province, average breeding density is estimated at 1 pair/167.5 km 2
(Mundy et al. 1992: 215). Small exclusive breeding territory, ca 30 m in diameter, is
maintained around nest only; however, Verreaux’s Eagles (Aquila verreauxii) are chased at
250 m (Mundy et al. 1992: 215). Most ‘courtship flights’ are initiated by the male who flaps up
behind the female when she is gliding in the vicinity of the nest, this is followed for a few
minutes by shallow undulations, either sex may lead (Mundy et al. 1992: 213). One bird flies
upwards to a height and dives down to the other which rolls on its back and they engage
talons: the diving bird calls shrilly (commonly observed among large raptors: Simmons and
Mendelsohn 1993). Up to 14 such dives may occur. With talons locked they may fall through
the air for a few hundred metres. Thereafter, they may land on a ledge and allopreen (Mundy
et al. 1992: 214). Allopreening between partners is common, especially in the early morning
and late afternoon (Mundy et al. 1992: 214). Copulation is preceded by a bout of allopreening,
usually initiated by the male (Mundy et al. 1992: 214). They may also rub faces and heads
together, sometimes the male bows a few times and even stamps his feet as if marching. The
female stands next to the male slightly crouched before copulation that may take only a few
seconds, occasionally they make a few soft high-pitched calls (Mundy et al. 1992: 214). Prebreeding
courtship feeding has not been recorded.
Nest: Males bring the sticks, carried lengthways, eagle-like, while females undertake the
construction and help to provide the lining (Mundy et al. 1992: 215). They always nest on
cliffs, usually in potholes or small caves, sometimes on ledges (Mundy et al. 1992: 214). In
southern Africa nest sites on basalt cliffs average 195 m above ground and 2 814 m above
sea level while those on sandstone average 47 m above ground and 1 935 m above sea level
(Mundy et al. 1992: 214). The range of 74 nests in southern Africa was 24-732 m above
ground and 1 850-3 200 m above sea level (Mundy et al. 1992: 214). The nests on exposed
ledges were at lower altitudes and not susceptible to snowfalls. Pairs may have from one to
eight alternative nests ranging from 2 m to 2 km apart, average = 230 m (Mundy et al. 1992:
214). Often use an alternative nest site each year, usually refurbishing an existing nest,
11