Marin County
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Common Loon, breeding
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Duck-like Birds |
Common Loon Gavia immer
Description ADULT In summer has iridescent greenish black head and neck; note two rows of white stripes on neck. Blackish upperparts have checkerboard-like pattern of white spots on mantle and smaller white spots elsewhere. Underparts are white and bill is dark. In winter, has dark gray upperparts and whitish underparts; note dark half collar. Pale gray bill has noticeably darker culmen. JUVENILE Similar to winter adult, but upperparts are brownish gray, scaly-looking on back.
Dimensions Length: 28-36" (71-91 cm)
Habitat Fairly common on large lakes in breeding season. In winter, favors rocky coasts and large lakes inland.
Observation Tips Most fish-rich lakes within breeding range support a pair in summer.
Range Plains, Rocky Mountains, Great Lakes, Northwest, Eastern Canada, California, Texas, Western Canada, New England, Florida, Alaska, Southwest, Southeast, Mid-Atlantic
Voice Utters evocative, wailing cry and eerie yodeling sound on breeding grounds.
Similar Species Yellow-billed Loon G. adamsii (L 34-35 in) has similar summer and winter plumage. Pale yellow bill is straight, with paler culmen (concave and dark in Common); bill and head are held tilted upward. Juvenile is similar to winter adult with scaly-looking back. Locally common high Arctic breeder. Scarce on east coast in winter. Pacific Loon G. pacifica (L 24-26 in) is smaller, with a daintier bill. In summer, has black back with white checkerboard-like pattern of white spots, white underparts, black throat, and otherwise gray head and neck, with black and white stripes on side; in winter, has mainly dark upperparts and white underparts, throat, and front of neck. Breeds in Arctic, west from Hudson Bay. Winters mainly on Pacific; rare in East.
Discussion Elegant waterbird. Long, pointed bill held horizontally or only slightly elevated. In flight, head and neck held outstretched and feet and legs trailing behind (true of all loons). Dives for fish. Sexes are similar.
