Iceland Gull
Larus glaucoides
Pale, medium-sized gull, smaller and daintier than Glaucous or Herring Gulls. Often looks cute with rounded head and small bill. Extremely variable plumage. Variation is apparently clinal across the Arctic breeding range, from darkest in the west to palest in the east. The palest adults have very pale gray backs and nearly pure white wingtips. The darkest birds, formerly known as Thayer’s Gull, are darker gray above and have blackish wingtips. Young birds range from almost pure white to medium brown, never as dark as Herring Gull. First-year birds usually have a mostly dark bill. Winters along both coasts of North America and in Europe, often near the ocean or on large lakes. Typically found in small numbers among flocks of other large gulls.
识别特征
The Iceland gull is a medium-sized gull, although relatively slender and light in weight. In length, it can measure from 50 to 64 cm (20 to 25 in), wingspan is from 115 to 150 cm (45 to 59 in), and weight is from 480 to 1,100 g (1.06 to 2.43 lb). Among standard measurements, the wing chord is 37.9 to 44.3 cm (14.9 to 17.4 in), the bill is 3.6 to 5.4 cm (1.4 to 2.1 in), and the tarsus is 4.9 to 6.7 cm (1.9 to 2.6 in). It is smaller and thinner-billed than the very large glaucous gull, and is usually smaller than the herring gull. It takes four years to reach maturity.
分类信息
The American taxon of Iceland gull by the American Ornithological Society as of 2017 considers the following as subspecies:<p>The nominate subspecies, L. g. glaucoides, is very pale in all plumage, with absolutely no melanin in the tips of the primaries in adult plumage. Adults are pale grey above, with a yellowish-green bill. Immatures are very pale grey; the bill is more extensively dark than with glaucous gull, and lacks pink.
- 学名
- Larus glaucoides
- 命名信息
- Meyer, B, 1822
- 目
- Charadriiformes
- 科
- Laridae
- 属
- Larus
分布与栖息地
- 繁殖区
- NA, PAL : Arctic ne Canada to Greenland
- 非繁殖区
- coastal Iceland to nw Europe, Labrador to wc North Atlantic coast, and ec North Pacific coast
- 迁徙
- Complete migrants
行为
It is migratory, wintering from in the North Atlantic as far south as the British Isles and northernmost states of the eastern United States, as well as in the interior of North America as far west as the western Great Lakes. It is much scarcer in Europe than the similar glaucous gull.<p>This species breeds colonially or singly on coasts and cliffs, making a nest lined with grass, moss, or seaweed on the ground or cliff. Normally, two or three light brown eggs are laid. They breed in Canada and Greenland, but not in Iceland.<p>Like most Larus gulls, these are omnivores, eating fish, molluscs, offal, scraps, and eggs. They forage while flying, picking up food at or just below the water's surface, and they also feed while walking or swimming. Their scavenging habits lead them to frequent garbage dumps, sewage outlets, and places where fish are cleaned.
保护状况
- 种群趋势
- stable
照片
分布
鸟叫声
其他鸟类
Brown-backed Chat-Tyrant
Ochthoeca fumicolor
Characteristic and often conspicuous flycatcher of the high Andes. Note its pale eyebrow, tan wingbars and mostly cinnamon underparts. Similar to Rufous-breasted Chat-Tyrant, but cinnamon on underparts extends to belly and does not form distinct breast patch. Found in elfin forest and scrub near or above treeline. Vocalizations include shrill squeaks and sharp “dewit” calls, often given by pairs in a jumbled duet.
Pohnpei Fantail
Rhipidura kubaryi
Dark gray fantail with white-edged scaling on the breast. Also note white “eyebrows”, malar stripe, and trimming on the tail. No confusion species; the only fantail on Pohnpei. Inhabits brushy and wooded areas, sometimes near human habitation. Like other fantails, a very active hunter, constantly hawking and gleaning for prey. Song is a high-pitched jumble of notes given in an up-and-down series.
Imperial Cormorant
Leucocarbo atriceps
Very striking cormorant readily identified by white neck. Locally common black-and-white cormorant of colder coastal waters. Often seen perched on inshore rocks and jetties, sometimes with Magellanic Cormorant. Nests colonially on low islands (rarely in lakes inland from coast) and jetties. Plumage varies regionally, with some birds black-faced and others white-faced; the two types breed together locally in the Strait of Magellan. Immature resembles adult but plumage duller overall, brownish above.
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