Bobolink
Dolichonyx oryzivorus
Breeding male is distinctive with black body, white rump, and creamy nape. Females and nonbreeders are drastically different, yellow-brown with fine streaking on breast sides, and stripes on head. Smaller than Red-winged Blackbird with shorter bill. Spiky tail feathers. In the blackbird family, although often mistaken as a sparrow. Breeds in open fields. Listen for male's bubbly song. Often in flocks during fall migration; departs early for wintering grounds in South America.
识别特征
Measurements:<p>Adults are 16–18 cm (6.3–7.1 in) long with short finch-like bills and weigh about 28 g (1 oz). Adult males are mostly black with creamy napes and white scapulars, lower backs, and rumps. Adult females are mostly light brown with black streaks on the back and flanks, and dark stripes on the head; their wings and tails are darker.
分类信息
Genus: Dolichonyx; Family: Icteridae; Order: Passeriformes.
- 学名
- Dolichonyx oryzivorus
- 命名信息
- (Linnaeus, 1758)
- 目
- Passeriformes
- 科
- Icteridae
- 属
- Dolichonyx
分布与栖息地
The bobolink breeds in the summer in North America across much of southern Canada and the northern United States; from 1966 to 2015 the species experienced a greater than 1.5% annual population decrease throughout most of its breeding range, extending from the Midwestern United States to the Canadian Maritimes. The bobolink migrates long distances, wintering in southern South America. One bird was tracked migrating 12,000 mi (19,000 km) over the course of the year, often flying long distances up to 1,100 mi (1,800 km) in a single day, then stopping to recuperate for days or weeks.<p>Bobolinks often migrate in flocks, feeding on cultivated grains and rice, which leads to them being considered a pest by farmers in some areas. Although bobolinks migrate long distances, they have rarely been sighted in Europe — like many vagrants from the Americas, the majority of records are from the British Isles.<p>The species has been known in the southern United States as the "reedbird," or the "ricebird" from their consumption of large amounts of the grain from rice fields in South Carolina and the Gulf States during their southward migration in the fall. One of the species' main migration routes is through Jamaica, where they are called "butter-birds" and at least historically were collected as food, having fattened up on the aforementioned rice.<p>Bobolinks are the only species of land bird known to annually migrate through the Galápagos Islands, which are over 2,000 km from their primary migration route. A bobolink was collected in the Galápagos Islands by Charles Darwin in 1835. Bobolinks have been hypothesized to act as vectors for avian malaria-causing parasites arriving in the Islands. Additionally, bobolinks in the Galápagos have been found with seeds from Drymaria cordata, a plant native to the Galápagos but highly invasive elsewhere, entangled in their feathers, potentially spreading them to the mainland.
- 繁殖区
- NA : s Canada and n USA
- 非繁殖区
- c SA
- 迁徙
- Complete migrants
行为
Migration pattern: Complete migrants.
保护状况
Population trend: declining.
- 种群趋势
- declining
照片
分布
鸟叫声
其他鸟类
Saker Falcon
Falco cherrug
Large, powerful falcon. Inhabits a range of expansive habitats, from grasslands and mountainsides to open woodlands. Somewhat variable, but always dark "trousers" when perched; the tail extends beyond the wingtips at rest, giving it a “short-winged” appearance. Some birds can appear pale-headed due to light-colored crowns and sparsely-marked faces. In flight, the wings are broad, with dark underwing coverts. Adults have a thin “teardrop” eyeline, whereas juveniles have a thicker one. Compare to similar Gyrfalcon and Peregrine Falcon; note “trouser” color and consistently brown upperparts. Feeds on small mammals and birds.
White-tipped Swift
Aeronautes montivagus
Fairly distinctive swift found in northwestern South America. Medium-sized with slightly notched tail. Blackish overall with a white throat and white band across the lower belly. Namesake white tips on tail can be difficult to see. Compare with Andean Swift, which has longer, more sickle-shaped wings, a deeper forked tail, and more extensive white on the breast. White-tipped is typically found in small flocks at fairly high elevations, from around 1,300 to 2,700 m (higher than Lesser Swallow-tailed Swift), and often does not associate with other swift species. Occurs over a variety of habitats including forest and drier, more open areas.
Bermuda Petrel
Pterodroma cahow
Endangered Atlantic Ocean seabird that nests on Bermuda and disperses widely when not breeding. Handsomely patterned with dark gray and white; note especially the gray on crown, nape, and face that extends unbroken down the sides of the neck in a cowl. The latter feature is usually lacking in the otherwise similar Black-capped Petrel; Bermuda Petrel also typically has a narrower white collar and less white on the rump. When not nesting, it can only be seen far from land, where it often flies in swooping arcs with little flapping. Locally known as “Cahow”, it very nearly went extinct in the mid-twentieth century, but was returned from the brink largely due to the heroic efforts of local conservationists.
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