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Red-throated Loon

Although it's usually not in its namesake breeding plumage while in Washington during winter, the Red-throated Loon gives some strong ID clues.

Length: 25 inches

Wingspan: 36 inches

Weight: 3.1 pounds (1,400 grams)

AOU code: RTLO

By Andy McCormick

Red-throated Loon, by Gary LuhmThe Red-throated Loon is named after the inverted triangular red patch on its throat in breeding plumage. It is winter when the bird is seen in Washington waters, however, and then its throat and the side of its face are white. (See right.)

Still, at any time of year the Red-throated Loon has a unique appearance that aids identification. In flight it keeps a low profile: Its head and bill are small and its long, thin neck is lower than its back, giving it a fairly distinctive humpbacked look. While sitting on the water, this loon’s spine is structured so that its bill is held up at an angle. This is best seen in profile.

Photos: Red-throated Loon in non-breeding plumage (above) and in breeding plumage (below), both by Gary Luhm

Light and Quick

Despite sharing the genus Gavia, Latin for seabird, the Red-throated Loon has unique features that separate it from the other four loons worldwide that share the genus. The Red-throated is smaller and lighter than all the other loons. It breeds farther north.

Unique among the loons, it takes flight more quickly and does not need a long running start at takeoff. It can also take off from land (Kaufman). It is the only loon that forages away from its nesting pond and, like some alcids, it carries fish back to its young (Barr, et al).

The species name stellata refers to being adorned with stars, and refers to the white speckling on the back in non-breeding plumage (Holloway).

Red-throated Loon (Breeding), by Gary LuhmThe Red-throated Loon is a breeding bird of the Arctic tundra and coastal plain. It has strong site fidelity and often uses the same nest for many years. Pairs are thought to mate for life, but this has not been proven.

Because the Red-throated Loon does not need a long run along the water to take flight, it often breeds on freshwater ponds and lakes smaller than those used by other loons. Its nest is constructed of a mass of vegetation and may be on the shore or floating on the water.

Typically two olive-colored eggs with dark brown spots are deposited. Incubation, mostly by the female, lasts about four weeks. The hatchlings take to the water in about a day and take first flight in another seven weeks.

Best Seen in Bad Weather

The Red-throated Loon makes its diet primarily of marine fish, usually caught along the coast or in tidal estuaries. In winter it is almost always seen on the ocean, and good looks can often be had in harsher weather when it tends to move closer to shore and forage in shallow water.

The world population of Red-throated Loons is estimated at around 100,000 individuals (Barr, et al). The western Alaskan population dropped about 50 percent from 1977 to 1993 (Alderfer, Barr et al).

The cause of the decline is not known, but scientists have some theories. For one, the Pacific Loon population is larger than that of the Red-throated, and the two species compete for space in breeding areas. Also, oil spills are a threat to Red-throated Loons, and large numbers of the birds are caught in fishing nets worldwide. Acidification in ponds is another possible cause of decline.

For references, email Andy McCormick: amccormick@eastsideaudubon.org

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