Southern Ground-Hornbill

识别特征

This is a large bird, at 90 to 129 cm (2 ft 11 in to 4 ft 3 in) long. Females weigh 2.2 to 4.6 kilograms (4.9 to 10.1 lb), while the larger males weigh 3.5 to 6.2 kilograms (7.7 to 13.7 lb).[citation needed] The average weight of eight females was 3.34 kg (7.4 lb) whilst that of eight males was 4.2 kg (9.3 lb); thus they average around 35% percent heavier than any Asian hornbill species. Wingspan is from 1.2 to 1.8 m (3 ft 11 in to 5 ft 11 in). The wing chord is 49.5 to 61.8 cm (19.5 to 24.3 in), the tail from 29 to 36 cm (11 to 14 in), the tarsus from 13 to 15.5 cm (5.1 to 6.1 in) and the culmen from 16.8 to 22.1 cm (6.6 to 8.7 in). Stevenson and Fanshawe report that the Abyssinian ground hornbill is the larger species on average, at 110 cm (43 in), than the southern species, at 102 cm (40 in), but published maximum weights and standard measurements indicate the southern species is slightly larger. Average weights are not known for the Abyssinian species.<p>The southern ground hornbill is black with vivid red patches of bare skin on the face and throat (yellow in juvenile birds), which are believed to keep dust out of the birds' eyes while they forage during the dry season. The white tips of the wings (primary feathers) seen in flight are another diagnostic characteristic. The beak is black and slightly curved and presents a casque, more developed in males. Female southern ground hornbills are smaller and have violet-blue skin on their throats. Juveniles to six years old lack the prominent red pouch, having a duller patch of grey in its place.

分类信息

学名

Bucorvus leadbeateri

命名信息

(Vigors, 1825)

目

Bucerotiformes

科

Bucorvidae

属

Bucorvus

分布与栖息地

迁徙

Resident species

保护状况

The southern ground hornbill is classed as vulnerable to extinction globally; however, in South Africa, where most studies on the species have been carried out, it is listed as endangered. They have also been classified as endangered in Lesotho, Namibia and Swaziland. Southern ground hornbills in these countries, along with Kenya, Tanzania, Malawi, Zambia, Zimbabwe, and Mozambique, require conservation interventions to help increase their numbers. The bird's classification as endangered is heavily tied to its slow reproductive rates. Habitat loss, changes due to the agriculture, deforestation, electrocution from power lines, accidental poisoning, and persecution are the major factors that affect their populations.<p>Persecution and hunting of the southern ground hornbill by human populations have continued to be complex issues. Recent studies have found the species has been hunted more than previously believed, including in protected areas. The majority of this hunting has likely been opportunistic. Overall, hunting is likely not a key driver for their lowering numbers. However, it is still a factor of which to be aware when considering conservation efforts, especially because of their low reproductive rates and an incomplete knowledge about local hunting habits in their natural regions. Furthermore, the southern ground hornbill faces persecution due to behaviors like destroying windows in response to seeing its reflection. Annoyed homeowners in urban areas in South Africa have been known to kill birds that destroy property.<p>The role of southern ground hornbills in a variety of cultural beliefs also influence conservation efforts. Some of these beliefs benefit their preservation. An example is the Ndebele, who believe killing southern ground hornbills is taboo due to their negative associations. However, the birds are also used in traditional cultural practices and medicines which can be harmful. In some marketplaces and cultures, southern ground hornbills are used in traditional medicines, which often rely upon harvesting specific parts of the bird. To date, research suggests that cultural uses do not have a significant impact on their populations. For example, the Ndebele healers use the bird for traditional medicine, but must follow a strict ritual process that could take months or years to prepare. Additional research documents plant alternatives to southern ground hornbill use for cultural belief uses. While investigation into traditional medicine trade of the southern ground hornbill has occurred, the bushmeat trade remains poorly understood, and it has only been seen to occur in areas of Malawi.<p>This bird species is especially threatened by the loss of trees and general habitat loss, as they require vast amounts of space for their territories. The removal of large trees for agriculture or wood harvesting, disturbances near nesting grounds, agricultural changes, all deeply affect the ability of southern ground hornbills to flourish. Due to the encroachment of human populations, it is not unheard of to see a group's territory encompass a variety of areas, from pristine habitats to commercial agricultural lands.<p>Southern ground hornbills can have clutches ranging from one to three eggs, but only one of these are raised. With only one egg being raised, conservationists have taken it as an opportunity to raise the remaining eggs in captivity. Rehabilitation projects, such the Mabula Ground Hornbill Project, have been hand-rearing these extra chicks with the goal of reintroducing them to the wild, although reintroducing this species has proven challenging.

种群趋势

declining