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Jul 07 2011

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Arctic Loon (Gavia arctica)

Arctic Loon

[order] GAVIIFORMES | [family] Gaviidae | [latin] Gavia arctica | [UK] Arctic Loon | [FR] Plongeon arctique | [DE] Prachttaucher | [ES] Colimbo Artico | [NL] Parelduiker

Subspecies

Monotypic species

Genus

The genus gavidae is formed by five species exclusively from the Northern Hemisphere. All of them are rather large birds, breeding in the arctic and boreal zone of Eurasia and North America. Although ranges overlap a great deal, identification is pretty straightforward. The bills are so distinctive that it is easy to tell them apart, with the exeption of the Pacific and Arctic Divers which are rather similar.

Physical charateristics

Medium-sized diver between Red-throated G. stellata and Great Northern G. immer in build. Adult breeding: upperparts blackish with rectangular white spots on back, most prominent on scapulars, and white below with black and white streaks on sides of upper breast. Head and neck grey, palest on hindneck, with black and white vertical stripes on sides of neck bordering black throat patch. Adult non-breeding: Dark grey-brown on head and upperparts clearly demarcated from white throat and underparts. Crown and nape are paler than back (unlike Great Northern) and flanks often show a white patch visible on a swimming bird. Intermediate build and bill held straight are best identifying features but very difficult to separate from Pacific Diver and may not be possible with non-breeding birds.

Listen to the sound of Arctic Loon

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Copyright remark: Most sounds derived from xeno-canto

wingspan min.: 100 cm wingspan max.: 122 cm
size min.: 63 cm size max.: 75 cm
incubation min.: 38 days incubation max.: 30 days
fledging min.: 60 days fledging max.: 30 days
broods: 1   eggs min.: 1  
      eggs max.: 3  

Range

Eurasia : also West Alaska

Habitat

Breeds beside medium-large freshwater lakes, often with islands. On passage and in winter moves to coastal areas and occurs on estuaries, bays and sheltered seas.

Reproduction

Breeds early-May to September, begins mid-June in north of range. Nests beside water often on an island or spit, a shallow scrape or more rarely a substantial mound of vegetation built in shallow water. Clutch 2 (1 in replacement clutch), olive-brown, sometimes more greenish with sparse black blotches (84 x 53mm). Incubated by both sexes for 28-29 days. Young tended by both sexes, feed themselves at 35 days and fly at about 60 days

Feeding habits

Fish, also molluscs and crustaceans caught during 45-120 second dives

Conservation

This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). Despite the fact that the population trend appears to be decreasing, the decline is not believed to be sufficiently rapid to approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size is very large, and hence does not approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.
Gavia immer has a predominantly North American breeding range, but also breeds
in the European Arctic. Its European breeding population is very small (as few as
700 pairs), but was stable between 1970-1990. Trends were not available for Greenland
and Iceland during 1990-2000, but there is no evidence to suggest that the species
declined. Although the size of the European population could render it susceptible
to the risks affecting small populations, it is marginal to a much larger non-European
population.
Arctic Loon status Least Concern

Migration

Migratory and dispersive. Some Scottish breeding lochs deserted August, but movement to salt water chiefly September-October; return about April. In Lapland and Russia, timing of movements to and from breeding lakes associated with thawing and freezing of fresh waters; spring return faster. Some reach Baltic by September and most at sea by mid-October. Main departures from Baltic and Black Sea winter quarters from mid-April to mid-May

Distribution map

Arctic Loon distribution range map

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