Cape vulture

Description

This large vulture is of a creamy-buff colour, with contrasting dark flight- and tail-feathers. The adult is paler than the juvenile, and its underwing coverts can appear almost white at a distance. The head and neck are near-naked. The eyes are yellowish, and the bill is black. Juveniles and immatures are generally darker and more streaked, with brown to orange eyes and red neck.

The average length of adult birds is about 96–115 cm (38–45 in) with a wingspan of 2.26–2.6 m (7.4–8.5 ft) and a body weight of 7–11 kg (15–24 lb). The two prominent bare skin patches at the base of the neck, also found in the white-backed vulture, are thought to be temperature sensors and used for detecting the presence of thermals. The species is among the largest raptors in Africa, next to the lappet-faced vulture. After the Himalayan griffon vulture and the cinereous vulture, the Cape vulture is the third largest Old World vulture.

Habitat and distribution

The Cape vulture occurs in Angola, Botswana, Lesotho, Mozambique, South Africa, and Zimbabwe. Formerly, it could also be found in Namibia and Swaziland. Vagrants are occasionally recorded from the Democratic Republic of the Congo and Zambia.

The species usually breeds and roosts on cliff faces in or near mountains, from where it can fly long distances in search of the large animal carcasses on which it specializes. Tracked specimens in Namibia were found to have home ranges 11,800–22,500 km² (4,600–8,700 sq mi) in extent.

In the Eastern Cape of South Africa, Cape Vultures were more likely to occupy cliff nest sites on ledges with a smaller depth and at a higher elevation, surrounded by conspecifics.

Conservation and threats

The Cape vulture has been declining steadily since at least the 1980s, when it was first categorized as Threatened. Between 1992 and 2007 the species declined by 60-70% in South Africa alone. It was later upgraded to Vulnerable and, in 2015, to Endangered. As of 2013, estimates of total population size assume about 4,700 pairs or 9,400 mature individuals.

The species is considered to be impacted by a large number of threats. A decrease in the amount of large carrion (particularly during nesting), poisoning (targeted or inadvertent), electrocution or collision with cables on electricity pylons (the most common cause of death in ringed birds), loss of foraging habitat, and unsustainable harvesting for traditional uses are thought to be the most important factors. A source of poisoning specific to many vultures, including the Cape vulture, is the drug Diclofenac and related compounds, which is used to treat arthritis in cattle, and which leads to kidney failure in vultures who consume carcasses of treated cattle.

On the 20th of June 2019, the carcasses of 468 white-backed vultures, 17 white-headed vultures, 28 hooded vultures, 14 lappet-faced vultures and 10 cape vultures, altogether 537 vultures, besides 2 tawny eagles, were found in northern Botswana. It is suspected that they died after eating the carcasses of 3 elephants that were poisoned by poachers, possibly to avoid detection by the birds, which help rangers to track poaching activity by circling above where there are dead animals.