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Bird Species of the World's Boreal Forests

MAMMALS

   
Gavia stellata
Red-throated Diver

Description

Distinguishing Features - The red-throated diver is the smallest of the divers, also called loons. Length: 53 - 69 cm. Wingspan: 106 - 116 cm. During the breeding season, the upper body is a solid dark brown. The head and upper neck is grayish, with a large, glossy colored patch on the foreneck. It is white underneath and the tail is dark. In the winter, the face and foreneck are pure white, and the upper part is dark brownish and finely spotted with white. Males average slightly larger than females, and have a heavier head and bill. Its neck is thick, and the nostrils are narrow and elongated, as an adaptation to diving. The iris is reddish, especially in adults during the breeding season. The body is designed for swimming, with short, strong legs set far back on the body. The legs are perfect for moving through water, although this design makes walking on land difficult. The three front toes are webbed, and these loons have short, well-defined tails.

Habitat

Red-throated Diver Breeds far into the high Arctic, and winters mainly on the northern coasts of the Atlantic and Pacific. Also in the Great Lakes of North America, the Black, Caspian, and Mediterranian Seas. It breeds mostly on fresh water, generally in fairly open marshes; often found to be nesting by small pools. It winters on inland waters along sheltered coasts on freshwater lakes and rivers; occasionally away from water.

Diet

Food consists of small or medium sized fish, including cod, herring, sprat, sculpins, and occasionally crustaceans, mollusks, frogs, fish spawn and insects. Prey is usually caught underwater and is usually swallowed before surfacing.

Notes

As a species, loons and divers are usually extremely awkward on land. However, red-throated divers have been known to travel long distances on shore. When seriously disturbed, they may even move cross-country to a new pool with their chicks. It is the lightest and most agile species of the genus and it has the largest wing-beat amplitude, and only the red-throated diver can take off from the ground, or land directly on it.

The diver's characteristic call is extremely loud and can be heard far away. It is used to proclaim the occupation of a territory. It sounds like a long, low-pitched whistle with some very clear notes interspersed. It is made by both mates at once. When disturbed or threatened, the red-throated diver produces a raven-like croaking call of warning. It also uses a short, frequently repeated, gooselike cackle, which it gives when flying over its own or neighboring territory. Red-throated divers, as most loons, have a variety of ritualized behaviors, including a series of stereotyped swimming ceremonies, which are performed by pairs.




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