Lava Gull
Leucophaeus fuliginosus
Distinctive gull endemic to Galápagos. Adult is easy to identify by sooty-gray body, black head, white crescents above and below eye, and pale rump. Juvenile is grayish brown with tan scaling on the back and wings, and a pale rump. Found along the coast, almost never venturing inland or very far out to sea. Forages along beaches and rocky shorelines, and often perches on boats and docks. It has the smallest population of any gull in the world, estimated at less than 1000 birds.
识别特征
The lava gull is a distinctive gull, 51 to 55 cm (20–22 in) and weighs 380 g (13 oz). The adult plumage consists of a sooty brown to black head, which unlike other dark hooded gulls doesn't vary by season. The wings are dark gray with a contrasting white line on the leading edge, thought to play a function in displays and camouflage. Its dark gray body contrasts with a paler gray belly. The uppertail is white and grey lower down. The bill and legs are black, and the inside of the mouth is scarlet. It has white upper and lower eyebrows, with red lids. Immature gulls are generally dark brown.
分类信息
First described by John Gould in 1841 from a specimen collected on Santiago Island in the Galápagos. The species is sometimes placed in the genus Larus. It is possibly closely related to the laughing gull.
- 学名
- Leucophaeus fuliginosus
- 命名信息
- (Gould, 1841)
- 目
- Charadriiformes
- 科
- Laridae
- 属
- Leucophaeus
分布与栖息地
The entire population lives on the Galapagos Islands where it is found predominantly on the islands of Santa Cruz, Isabela, San Cristobal and Genovesa. Previously its population was estimated at 300–400 pairs; this estimate was revised downwards to 300-600 individuals in 2015. It is currently considered the rarest gull in the world.
- 迁徙
- Resident species
行为
Unlike most gulls which nest close together and sometimes touching, lava gulls are solitary nesters, rarely nesting closer than 100 meters apart. They are highly territorial, defending breeding territories of roughly 2000 sq. meters (70 m diameter) from conspecifics. They nest on the ground, often under the protection of coastal vegetation, and line the nest with plant material. They lay two olive-colored and well-camouflaged eggs that take 32 days to incubate. They generally nest close to calm water, often near lagoons. Breeding appears to be opportunistic and is not restricted to a single season. Young birds fledge at 55 days and continue to be cared for by the adults for several weeks.<p>They are omnivores like most Larus gulls, generally scavenging or stealing from nests and from fishers, but will also catch fish, small crustaceans, and newly hatched lizards, iguanas, and turtles. They also feed on sea lion placenta. On Genovesa they exploit the kleptoparasitic behavior of the Magnificent frigatebird, capitalizing on the botched attempts by these frigatebirds to steal fish from various nesting seabirds. Potential nest predators include owls, frigatebirds and other lava gulls, as well as introduced mammals.<p>The lava gull is categorized as "vulnerable" by the IUCN Red List because it exists in small numbers and though the population is stable, it faces numerous threats.
保护状况
- 种群趋势
- stable
照片
分布
鸟叫声
其他鸟类
Bay-capped Wren-Spinetail
Spartonoica maluroides
Small, with a long spiky tail. Has a brown-streaked black back contrasting with a cinnamon crown and pale underparts. Note the pale eyebrow. Found in well-vegetated marshes and wet areas with tall grass. The song is an insect-like buzzy trill.
Pyrrhuloxia
Cardinalis sinuatus
Essentially a desert-dwelling cardinal, found in brushy areas of the southwestern U.S. and northern Mexico. Shaped much like a Northern Cardinal but with a longer, thinner crest and more rounded bill shape. Plumage is mostly gray with red highlights on the face, crest, belly, wings, and tail. Bill color is usually yellowish, but grayer on immatures. Usually seen in pairs or small flocks, often visiting bird feeders. Song is similar to Northern Cardinal but higher-pitched and more piercing.
Silver Pheasant
Lophura nycthemera
Large and spectacular pheasant found in forested areas. Variable across its large range, but the long-tailed male has either white or silvery-gray upperparts with a black crest, breast, and belly. Northern males are whiter above than their southern counterparts, though they still have some light black markings on the wings and back. Females are brownish overall with a much shorter tail. Both sexes have bright red face and legs. Hybridizes extensively with Kalij Pheasant where ranges overlap, producing variable intermediate hybrids.
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