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
Javan Hawk-Eagle
Nisaetus bartelsi
Medium-sized eagle with short, rounded wings. Adult is dark brown above and white with heavy streaking and barring below. Perched birds show a prominent vertical crest. When in flight, note prominent “fingers”, black-striped white throat, and bold black banding on the flight feathers and tail. Juvenile has a pale tan head and underparts, a shorter crest, and paler black banding on the wings and tail. Pale morph Changeable Hawk-Eagle can be similar, but note present species’ more densely patterned underparts and wings, taller crest, and tan (not white) head in juveniles. Endemic to Java, where it is now largely limited to foothill and montane forests. Soars often, but also frequently perches silently in the canopy. Quiet, but occasionally gives thin yelping screams.
Barrow's Goldeneye
Bucephala islandica
Striking diving duck of coastal harbors, mountain lakes, and large rivers. Very similar to Common Goldeneye. Males are easiest: Barrow’s has more black on the back, a downward-pointing spur on the side, and a crescent-shaped (not circular) white patch on the face. Females can be very difficult. Barrow’s usually has a yellow bill, but Common can rarely show a dull yellowish bill. Head and bill shape are important: Barrow’s has a steeper forehead and a puffy nape, and a shorter bill with a more rounded lower edge. Fairly common in western U.S. and Canada; much less common in the northeast. Small population in Iceland. Frequently found in mixed flocks with Common Goldeneye.
Malabar Whistling-Thrush
Myophonus horsfieldii
Deep blue ground-dweller with shining forehead and shoulder patches; belly can appear mottled blue-and-black in the right lighting. Inhabits foothills and montane forests, where it sticks closely to water, especially rocky streams and smaller rivers with overhanging vegetation and rocky ledges. Song is an eerie and human-like series of variable, deliberate-sounding whistles. Call is a high thin “tseeeeee.”
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