Red-throated loon
Gavia stellata
TAXONOMY
Colymbus stellatus Pontoppidan, 1763, Tame River, Warwickshire, England. Monotypic.
OTHER COMMON NAMES
English: Red-throated diver; French: Plongeon catmarin; German: Sterntaucher; Spanish: Colimbo Chico.
PHYSICAL CHARACTERISTICS
20.8–27.19 in (53–69 cm); 2.2–5.9 lb (1.0–2.7 kg). The smallest and least robust in the family, with proportionally smaller, upturned bill and smaller feet than other loons. Smaller size allows red-throated loons to take off directly from water and even from land. In alternate plumage, has grayish upperparts, white underparts, gray face, and brick red throat patch. In basic plumage, has grayish upperparts with white speckling, gray cap and nape, white underparts, throat, and face. Juvenal and second alternate plumages similar to basic plumage, with gray-brown wash on head and neck.
DISTRIBUTION
Breeding range is circumpolar, ranging farther north than other loons. Occupies coastal plain in Alaska, northern Canada, Greenland, Iceland, northern British Isles, Norway, Sweden, Finland, and across Russia. Winters on coasts on Atlantic and Pacific Oceans north of the tropic of Cancer, occasionally found inland. Migrates mostly along coast, occasionally over land.
HABITAT
Breeds mainly on ponds in coastal tundra, occasionally inland up to 3,511 ft (1,070 m) in elevation. Where it competes with other loons, occupies smaller (sometimes fishless) ponds too small for larger loons. In the far north where it is the only loon present, will breed on larger ponds and lakes. Winters on coasts, usually within 3 mi (5 km) of shore in areas with a soft, sandy substrate. Occasionally found inland on large lakes and rivers.
BEHAVIOR
The only loon to have duet vocalizations, given by pairs on breeding ponds. May migrate singly or in loose flocks. Does not require running start from water during take-off like other loons, and is the only loon that can take off from land.
FEEDING ECOLOGY AND DIET
Feeds on variety of small freshwater and marine fish. Will feed invertebrates to small chicks, and will feed on invertebrates as adults when fish are scarce. When breeding in fishless ponds, will fly to the coast and other ponds to catch prey to bring back to the young.
REPRODUCTIVE BIOLOGY
Breeds from May to September, depending on latitude and climate. Incubation 24–27 days. Occasionally moves from breeding
pond to a larger pond or the ocean. Chicks are more agile on land than are adults, and have been seen traveling over a kilo-meter over land. Young can fly after 38 days. Predators include Arctic fox (Aloplex lagopus) and other mammals, jaegers (Stercorarius), and gulls (Larus).
CONSERVATION STATUS
Declining over much of its range, although the cause is unknown. Not listed on IUCN Red List of Threatened Birds.
SIGNIFICANCE TO HUMANS
Inuit legally hunt around 4,600 loons (of all species) each year for subsistence; the proportion that are red-throated is unknown.
