Hartlaub's Gull
Chroicocephalus hartlaubii
A medium-sized, pale-gray-backed gull of coastal waters and human settlements. Breeding birds have dark eyes and a very faint chalky-gray hood, which non-breeding birds lack. This adaptable omnivore is the commonest gull of the Benguela Current, but its penchant for eating offal means it is expanding its range eastwards. The similar Gray-hooded Gull differs from Hartlaub’s Gull by being larger, having a yellowish-white eye, a longer redder bill, and a discrete grayish hood in breeding plumage. Immature Gray-hooded Gulls have a black terminal tail band which juvenile Hartlaub’s Gulls lack.
识别特征
Hartlaub's gull is 36–38 cm in length. It is a mainly white gull with a grey back and upperwings, black wingtips with conspicuous white "mirrors", and a dark red bill and legs. When breeding it has a very faint lavender grey hood, but otherwise has a plain white head. Sexes are similar. This species differs from the slightly larger grey-headed gull in its thinner, darker bill, deeper red legs, paler, plainer head, and dark eyes. It takes two years to reach maturity. Juvenile birds have a brown band across the wings. They differ from same-age grey-headed gulls in that they lack a black terminal tail band, less dark areas in the wings, darker legs, and a white head.
分类信息
- 学名
- Chroicocephalus hartlaubii
- 命名信息
- (Bruch, 1855)
- 目
- Charadriiformes
- 科
- Laridae
- 属
- Chroicocephalus
分布与栖息地
The gull is a non-migratory breeding resident endemic to the Atlantic Ocean coastline of South Africa and Namibia. Although it is predominantly coastal or estuarine, it is not a pelagic species, and is rarely seen at sea far from land. About one half of the total population, currently estimated at 30 000 birds, lives within the Greater Cape Town area. It has accommodated well to humans, and can become very tame around habitations. Although it is a relatively rare species, about the tenth rarest of the world's 50 or so gull species, it is common in its range and is widely regarded in Cape Town as a nuisance, fouling buildings and bathing in urban ponds. It has, at times, been a hazard to aircraft near airports.
- 迁徙
- Resident species
行为
Like most gulls, Hartlaub's is highly gregarious in winter, both when feeding or in evening roosts. This is a noisy species, especially at colonies. The call is a raucous crow-like kaaarrh. This species is frequently the subject of complaints about the noise it makes in urban areas.<p>Hartlaub's gull breeds in large colonies, and the main traditional breeding colony for the Cape Town area is on Robben Island. The adults fly to the mainland to find food for their chicks, a round trip of about 24 km.<p>The species is omnivorous like most Larus gulls, and they will scavenge at tips and feed on scraps as well as seeking suitable small prey, often by wading in shallow water.
保护状况
- 种群趋势
- rising
照片
分布
鸟叫声
其他鸟类
Winter Wren
Troglodytes hiemalis
Tiny, short-tailed, plain-brown wren with a huge voice. Subtly patterned, with indistinct pale eyebrow and diffuse dark barring on flanks and wings. Constantly keeps tail cocked at an angle. Found in a variety of forested habitats, but always prefers wetter areas with thick tangles, often around treefalls and moss. Darker, smaller, and shorter-tailed than House Wren. Incredibly beautiful song is a long series of musical whistles and trills; an unmistakable and common sound in northern forests. Call is a dry, low "chimp" remarkably similar to Song Sparrow.
Palau Kingfisher
Todiramphus pelewensis
A distinctive small kingfisher, white below with greenish-blue wings and a purplish-blue back. Shows a greenish cheek, a black eye-stripe extending behind the head, and an orange-rufous cap. Found in a wide variety of habitats including mangroves, wooded lowlands, plantations, and large gardens. Replaced by Pacific Kingfisher on the coast, but unlikely to be confused with it. Relatively quiet, but often gives a chattering ”che-che-che, che-kreek, kreek, kreek” at dawn and dusk.
Sharp-tailed Ibis
Cercibis oxycerca
A medium-sized wading bird, mostly black with a red bill and legs. Relatively long tail projection imparts a long-bodied appearance which is enhanced by its short legs. At close range, note bare red throat and orbital skin. Occurs in open wetlands and seasonally flooded savannas, usually in pairs or small groups, probing in mud, shallow water, or soft ground for invertebrates and fish. Unusual, far-carrying call is a single, horn-like note, often given in duet by pairs, with one higher-pitched than the other; the overall effect is like the braying of a donkey. Larger and longer-tailed than Bare-faced Ibis, much more vocal, and does not occur in large groups.
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