Gavia stellata

This is a clearly distinct taxon at the species level.

Not globally threatened; still numerous though may be declining locally (Hoyo et al. 1992).

Breeding in North America occurs on Arctic coasts and islands from Alaska to Ellesmere Island, south along the Pacific coast through the Aleutian Islands to Queen Charlotte and Vancouver islands; inland to central Yukon, southern Mackenzie, northeastern Alberta, northern Saskatchewan, around Hudson Bay, and along the Atlantic coast to southeastern Quebec. In Eurasia, the breeding range extends from Greenland, Iceland, and Arctic islands and coasts south to the British Isles, southern Scandinavia, northern Russia, Lake Baikal, Sakhalin, the Kuril Islands, Kamchatka, and the Commander Islands (AOU 1998). During the nonbreeding season, the range in North America extends from the Aleutians south along the coast to northwestern Mexico; and from southern Newfoundland to northeastern Florida and the Gulf Coast; in Eurasia south to Mediterranean, Black, and Caspian seas, and along the western Pacific coast to China and Taiwan (AOU 1998).

This species is represented by a large number of occurrences (subpopulations).

PREDATION: Predation is major cause of nesting failure (Eberl and Picman 1993). Predators include arctic fox, wolf, glaucous gull, jaegers, snowy owl, and probably other carnivores and raptors.

FLOODING: Flooding of nests and desiccation of ponds leading to stranding, abandonment, or predation may be minor factors of nesting failure (Eberl and Picman 1993).

CONTAMINATION: Given the fish diet, this species may be susceptible to mercury contamination in areas with acidified lakes. Eggs in Sweden, for example, revealed extremely high mercury levels (6.2-14.2 parts per million, dry weight). Residues of chlorinated hydrocarbons and heavy metals also found in tissue samples of birds found dead in Germany, 1980 to 1984 (Heidmann et al. 1988). Red-throated loon also may suffer from decline in food (fish) abundance due to lake acidification in some areas (Eriksson 1994).

HUMAN DISTURBANCE: Substantial numbers may drown as a result of entanglement in fishing nets in winter range (see Johnsgard 1987). As many as 73 percent of nests suffered from human-related disturbance on Igloolik Island, Northwest Territories (Forbes et al. 1992). Red-throated loons are sensitive to human intrusion and may abandon disturbed breeding lakes (Forbes et al. 1992, Hoyo et al. 1992).

Additional hazards include lake eutrophication, water level fluctuations (McIntyre 1994), and oil spills, especially near foraging areas. At least 201 birds found oiled in coastal Britain in 1970s (Hoyo et al. 1992).