Arctic Loon
A species of Loons, Also known as Black-throated Diver Scientific name : Gavia arctica Genus : Loons
Arctic Loon, A species of Loons
Also known as:
Black-throated Diver
Botanical name: Gavia arctica
Genus: Loons
Content
Description General Info
Photo By Steve Garvie , used under CC-BY-SA-2.0 /Cropped and compressed from original
Description
The adult black-throated loon is 58 to 73 cm (23 to 29 in) in length with a 100 to 130 cm (39 to 51 in) wingspan and a weight of 1.3 to 3.4 kilograms (2.9 to 7.5 lb). The nominate subspecies in its breeding plumage has a grey head and hindneck, with a black throat and a large black patch on the foreneck, both of which have a soft purple gloss. The lower throat has a necklace-shaped patch of short parallel white lines. The sides of the throat have about five long parallel white lines that start at the side of the patch on the lower throat and run down to the chest, which also has a pattern of parallel white and black lines. The rest of the underparts, including the centre of the chest, are pure white. The upperparts are blackish down to the base of the wing, where there are a few rows of high contrast white squares that cover the mantle and scapulars. There are small white spots on both the lesser and median coverts. The rest of the upperwing is a blackish colour. The underwing is paler than the upperwing, and the underwing coverts are white. The tail is blackish. The bill and legs are black, with a pale grey colour on the inner half of the legs. The toes and the webs are grey, the latter also being flesh coloured. The irides are a deep brown-red. The sexes are alike, and the subspecies viridigularis is very similar to the nominate except that the former has a green throat patch, instead of black. The subspecies viridigularis does still retain a purplish gloss, although it is less than the nominate. The non-breeding adult differs from the breeding adult in that the cap and the back of the neck are more brownish. The non-breeding adult also lacks the patterned upperparts of the breeding adult, although some of the upperwing coverts do not lose their white spots. This results in the upperparts being an almost unpatterned black from above. The sides of the throat are usually darker at the white border separating the sides of the throat and the front of the throat; most of the time a thin dark necklace between these two areas can be seen. There is white on the sides of the head that are below the eye. The bill is a steel-grey with, similar to the breeding adult, a blackish tip. The juvenile is similar to the non-breeding adult, but has a browner appearance. It has a buffy scaling on the upperparts that is especially pronounced on the scapulars. The lower face and front of the neck has a diffused brownish tinge. The juvenile does not have the white spots on the wing coverts, and its irides are darker and more dull in colour. The chick hatches with down feathers that range in colour from sooty-brown to brownish-grey, usually with a slightly paler head. The abdomen is pale. The black-throated loon can be distinguished from the Pacific loon by the white on the flanks of the former.
Size
56-71 cm (22-28 in)
Colors
Black
Gray
White
Purple
Life Expectancy
27 years
Nest Placement
Ground
Feeding Habits
Arctic Loon predominantly consumes fish, with a diet also including insects, molluscs, crustaceans, and plant matter. Solo or in pairs, arctic Loon forages by diving up to 5 meters deep at a high success rate, feeding away from the nest, especially when breeding. Unique adaptations include teaching chicks to feed—initially on invertebrates, transitioning to larger fish like salmonids as they grow.
Habitat
The black-throated loon has a large range, breeding taking place across northern Europe, Asia, and the Seward Peninsula in Alaska. When breeding, it is found in the area around isolated, deep freshwater lakes larger than 0.1 square kilometres (0.039 sq mi), especially those with inlets, as it prefers to face only small stretches of open water. When it is not breeding, this loon moves in a general southward direction and towards ice-free sea, usually wintering in coasts on north-east Atlantic Ocean and those on the eastern and western Pacific Ocean, such as the coasts of Japan. During this time, its habitat is usually inshore waters along sheltered coasts, although it will sometimes be found inland, in places such as the Mediterranean and Black seas.
Nest Behavior
Arctic Loon may be monogamous for life, engaging in bill-dipping and splash-diving courtship displays. Both sexes participate in nest building and maintenance.
Nest Characteristics
Arctic Loon constructs a nest that is a heap of vegetation, occasionally mingled with mud, located in shallow water, on an island, or by the shore. Rarely, arctic Loon may build a floating nest.
Dite type
Piscivorous
General Info
Feeding Habits
Bird food type
Behavior
Like other loons, this bird takes off by pattering on a "runway" of water. While flying, it makes a barking "kwow" flight call.
Distribution Area
The black-throated loon has a large range, breeding taking place across northern Europe, Asia, and the Seward Peninsula in Alaska. When breeding, it is found in the area around isolated, deep freshwater lakes larger than 0.1 square kilometres (0.039 sq mi), especially those with inlets, as it prefers to face only small stretches of open water. When it is not breeding, this loon moves in a general southward direction and towards ice-free sea, usually wintering in coasts on north-east Atlantic Ocean and those on the eastern and western Pacific Ocean, such as the coasts of Japan. During this time, its habitat is usually inshore waters along sheltered coasts, although it will sometimes be found inland, in places such as the Mediterranean and Black seas.
Species Status
Despite the fact that its population is declining, the black-throated loon is listed as a species of least concern by the IUCN. This is because the species has a large population and an extremely large range, and its decline does not appear to be rapid. In North America, it is protected under the Migratory Bird Treaty Act of 1918, while in Europe and Africa, it is protected under the Agreement on the Conservation of African-Eurasian Migratory Waterbirds.
Photo By Steve Garvie , used under CC-BY-SA-2.0 /Cropped and compressed from original