Least Tern
Sternula antillarum
Tiny tern with quick flicking wingbeats. A real beach bum, rarely straying far from sand, both on the coast and along inland rivers and lakes. Breeding adults have yellow bill, stumpy yellow feet, white forehead, and black cap. Nonbreeding and immatures have a black bill, blackish nape, and dark shoulder bar, but still always identifiable by size and quick wingbeats. Often seen with other terns. Listen for shrill high-pitched calls.
分类信息
- 学名
- Sternula antillarum
- 命名信息
- Lesson, RP, 1847
- 目
- Charadriiformes
- 科
- Laridae
- 属
- Sternula
分布与栖息地
- 繁殖区
- NA, MA : Great Plains to Texas and n Louisiana; c California and Gulf of California coasts to Oaxaca (w Mexico), El Salvador and Nicaragua; w North Atlantic coast from Maine to Florida, Gulf of Mexico and Caribbean Sea from Bahamas to Lesser Antilles, islands off Yucatan Pen., Belize and n Honduras, and islands n of Venezuela
- 非繁殖区
- n SA coast
- 迁徙
- Complete migrants
保护状况
The population is about 21,500 pairs; it is not currently considered federally threatened, though it is considered threatened in many of the states in which it breeds. Threats include egg and fledgling predators, high tides and recreational use of nesting beaches.<p>The interior subspecies, with a current population of about 7000 pairs, was listed as an endangered subspecies in 1985 (estimated 1000 breeding pairs), due to loss of habitat caused by dams, reservoirs, channelization, and other changes to river systems. It was delisted on 13 January 2021.<p>The western population, the California least tern, was listed as an endangered species in 1972 with a population of about 600 pairs. With aggressive management, mainly by the exclusion of humans via fencing, the Californian population has rebounded in recent years to about 4500 pairs, a marked increase from 582 pairs in 1974 when census work began, though it is still listed as an endangered subspecies. The California subspecies breeds on beaches and bays of the Pacific Ocean within a very limited range of southern California, in San Francisco Bay and in northwestern Mexico. While numbers have gradually increased with its protected status, it is still vulnerable to predators, natural disasters or further disturbance by humans. Recent threats include the gull-billed tern (Sterna nilotica), which can decrease reproductive success in a colony to less than 10%.
- 种群趋势
- declining
照片
分布
鸟叫声
其他鸟类
Cardinal Lory
Chalcopsitta cardinalis
A thick-bodied, long-tailed parrot with entirely red plumage. The head appears slightly brighter than the body. Widespread in most habitats up to around 1200 meters of elevation. Unlikely to be misidentified due to its unique entirely red coloration. Most common call is a high-pitched rising “tsleet!”
Vermiculated Fishing-Owl
Scotopelia bouvieri
A round-headed, gingery fishing-owl with heavily streaked underparts and a yellow beak. It is shy and day-roosts are well hidden in huge trees along rivers in lowland primary, swamp and flooded forests. The call is a deep low horn-like “hooooo”, and young birds sometimes emit an eerie screeching “wheeeuuu”. Similar Pel’s Fishing-Owl is larger and rustier (especially on the underparts) than Vermiculated Fishing-Owl, has a black (not yellow) beak, and is covered in spots, bars and chevrons.
Great Iora
Aegithina lafresnayei
A yellowish canopy-dweller with a long, powerful-looking bill. Male is dark above and yellow below, while female is ironically distinctive in her lack of distinctive characteristics; she is plain gray-green above and yellow below. Both sexes can be separated from other ioras by the proportionally larger bill, greater size, and lack of wingbars. Inhabits primary and late secondary broadleaf forests, as well as forest edge, in lowland and foothill regions. Song is a rapid-fire series of high-pitched “chew” notes. Like other ioras, frequently joins mixed-species flocks.
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