Black Scoter

From SongbirdReMixWiki

Jump to: navigation, search


Common Name: Black Scoter
Scientific Name: Melanitta americana

Size: 17-19 inches (43-49 cm); Wingspan: 30.3-32.7 inches (77-83 cm)

Habitat: North America and Asia; breeds in the far north of North America in Labrador and Newfoundland to the southeast Hudson Bay, in Alaska. It also occurs on the Siberian side of the Bering Straits east of the Yana River. It winters further south in temperate zones, on the coasts of the northern USA and Canada, on the Pacific coast south to the San Francisco Bay region and on the Atlantic and Gulf of Mexico coasts, and in Asia as far south as China. Some birds may over-winter on the Great Lakes. This species is a very rare vagrant to Western Europe.

This species is strongly migratory and often travels considerable distances over land making brief stop-overs on inland waters. It arrives on its breeding grounds between late-April and May and breeds from late-May onwards in highly dispersed solitary pairs. After mating (from June onwards) males migrate long distances prior to their flightless molt, most travelling in small groups to inshore or offshore coastal waters. Females and juveniles leave the breeding grounds in September. The species is highly gregarious when not breeding with males forming large congregations during the flightless molting period and large flocks of several hundred to a thousand or occasionally over 100,000 individuals occurring during winter. Non-breeders often over-summer on the wintering grounds.

Their breeding habitat is on Arctic dwarf heath or boggy tundra on pools, small lakes, streams and slow-flowing rivers. It shows a preference for freshwater habitats with low banks, small islets with a high abundance of aquatic invertebrate and plant life, positioned in swampy valleys or among mossy bogs, especially where there are suitable shrubs (e.g. willow or birch) and herbaceous vegetation. It generally avoids areas with steep slopes or wetlands enclosed by forest. Non-breeding habitat: Although the species may use freshwater lakes on migration the majority molt and overwinter at sea on shallow inshore waters less than 20 m deep (optimally 5-15 m) with abundant benthic fauna, generally between 500 m and c.2 km from the shore.

Status: Near Threatened. Global population: 530,000-830,000 individuals. This species is thought to be declining in western Alaska and to be stable on the Arctic coastal plain. Numbers also appear to be declining in the Atlantic flyway. Trends are apparently uncertain in far north-east Asia, where the species occurs east of Lena and numbers an estimated 300,000-500,000 birds or 12-24% of the estimated global population.

The large concentrations of this species that occur during the molting period and in winter are highly vulnerable to oil spills, chronic oil pollution, human disturbance and the degradation of food resources as a result of oil exploration. The species also suffers disturbance from high-speed ferries. The effects of commercial exploitation of benthic shellfish also poses a threat (through competition for food resources), and the species’ breeding habitats are threatened by eutrophication (such as algae blooms) in some areas. The species is susceptible to avian influenza so may be threatened by future outbreaks of the virus.

Diet: Predominantly mollusks and other crustaceans during migration or wintering on the sea-coasts. During the nesting period, it feeds on insects and their larvae (especially caddisflies and fish eggs) and vegetation such as duck weed on freshwater. Food is obtained mostly through diving.

Nesting: Males are larger than females. Scoters have a bulky shape and large bill. The male is all black with a very bulbous yellow bill. The female is a brown bird with pale cheeks, very similar to female Common Scoter.

The lined nest (scrape type) is built on the ground close to the sea, lakes or rivers, in woodland or tundra. 5–7 eggs are laid. The incubation period may range from 27 to 31 days. Females brood their young extensively for about 3 weeks, after which the still flightless young must fend for themselves.

Cool Facts: This is America's only black duck, although the female may have some yellow around the nostrils.

Found in Songbird Remix Waterfowl Volume II: Diving and Sea Ducks

Personal tools