Ranging behaviour of Cape Vultures Gyps coprotheres from an endangered population in Namibia

Abstract

SummaryThe Cape Vulture (Gyps coprotheres) is an obligate cliff-nesting vulture endemic to southern Africa. Its range and population size have declined markedly over the last century. Namibia has just one colony, located on the cliffs of the Waterberg Plateau, with a population estimated to be eight adult birds, including two females. The species is regarded as Critically Endangered in Namibia, and establishing a secure breeding population may require intensive management. Data on movements, foraging range and behaviour of Cape Vultures, important in any management programme, have been lacking. Five adult males and one immature were captured near the Waterberg site and fitted with satellite-tracking devices. Only two of the adult vultures still roosted on the cliffs and only one of those exclusively; the other individuals roosted in trees. Three individuals were observed building and attending to nests in trees, and, for one of these, the partner was identified as an African White-backed Vulture (Gyps africanus). The foraging range of the adult birds was large compared with other studies of this species. Most foraging took place on freehold farms. All adults avoided areas of communally owned land where wild ungulates are uncommon, thus further decreasing their potentially available food supply. Two 'vulture restaurants', feeding sites specifically for vultures, within the foraging range of the adult birds accounted for a large proportion of their time spent on the ground. The ranging behaviour of adult vultures varied throughout the year, and was apparently related to their nesting behaviour.

Ranging Behaviour of Non-Breeding Eurasian Griffon VulturesGyps fulvus: A GPS-Telemetry Study

“…For example, Xirouchakis & Andreou (2009) reported range sizes ranging from 390 to 1300 km 2 (according to 100% MCP), and 380 km 2 -64 km 2 according to 95% and 50% kernel, respectively; whereas Gil et al (2009) reported maximum home-ranges between 23-161 km 2 . By contrast, the home-range size reported here was lower than those reported for satellite-tracked Cape Vultures Gyps coprotheres in Namibia, which were 21320 km 2 for adults and 482276 km 2 for juveniles (Bamford et al 2007). Differences in home-range size could be explained by the availability of suitable habitat for foraging, individual's age and sex, as well as the method used for tracking.…”

An effect of vegetation structure on carcass exploitation by vultures in an African savanna

“…It seems reasonable to assume that Cape Vultures achieve lower take-off angles than White-backed Vultures, and this would mean that some carcasses that were available to White-backed Vultures would not be available to Cape Vultures. Of the factors put forward to explain the decline in African vulture populations, the runway hypothesis is the only one so far shown to affect species differently, perhaps explaining why, for example, the Namibian population of the Cape Vulture is declining (Bamford et al 2007), while that of the White-backed Vulture in the area is flourishing. …”

Dead or alive? Comparing costs and benefits of lethal and non-lethal human–wildlife conflict mitigation on livestock farms

“…It is commonly unselective and there is little evidence of cost-effective diminution of livestock losses (Treves & Naughton-Treves, 2005;Berger, 2006), as predators learn to avoid control efforts (Brand et al, 1995;Knowlton et al, 1999). Methods such as leg-hold traps, snaring and poisoning are largely indiscriminate and often kill non-target species (Rochlitz et al, 2010); in South Africa, this includes threatened species such as Cape vultures Gyps coprotheres (Bamford et al, 2007). Unintended outcomes of removing territorial predators can include an influx of replacement individuals, potentially increasing the local predator population and the risk of depredation (Crooks & Soulé, 1999;Knowlton et al, 1999), through what are known generically as perturbation effects (Tuyttens & Macdonald, 2000).…”