Bird of the Month - Pacific Loon
By Andy McCormick
Pacific Loon: Gavia pacifica
Weight 3.1 lb (1400 g)
AOU Alpha Code PALO
A western U. S. specialty the Pacific Loon is most well known as a spring and fall migrant along the Pacific coast.
The Pacific Loon is a medium-sized waterbird smaller than Common Loon (G. immer) and about the same size or slightly larger than Red-throated Loon (G. stellata). In fall migration it is usually seen in its basic plumage marked by dark gray on the crown, hind neck, and back with a small amount of white showing on the sides as it sits in the water. Most adults in winter sport a thin black “chinstrap.” Juveniles do not show a chinstrap. Identification is aided by the clearly defined vertical separation between black and white on this loon’s neck.
In spring Pacific Loons migrate offshore in abundance and will be in their alternate (breeding) plumage with a pale gray head and back of the neck, black throat, and narrow white streaks on the sides of the neck. They have a checkerboard black and white back similar to that of Common Loons.
HIGH ARCTIC BREEDER
Pacific Loons greatly expand their range eastward during the breeding season as they nest across northern Canada on lakes surrounded by tundra or in forested country. They build a nest at the edge of water by pulling up vegetation from around the nest site. Usually two eggs are deposited and incubated for 24-25 days. Young leave the nest shortly after hatching but will return for rest periods. First flight will occur after two months growth (Kaufman).
Loons are placed in the genus Gavia from the Latin for seabird. Its species name pacifica reflects the U.S. range of the bird along the Pacific Coast. The name loon may be a corruption of the Shetland loom, their name for a guillemot, or a diver (Holloway).
WINTERS OFF CALIFORNIA AND MEXICO
Pacific Loons migrate along the Pacific Flyway usually staying off shore in deeper waters. However, they will forage on Pacific sand lance, Pacific herring, and other small fish during tide changes and areas with strong currents. They are regularly seen in October and November off Point No Point in Kitsap County during incoming tidal rips. Videos of Pacific Loons flying and foraging in the ocean can be seen at the Macaulay Library
In winter Pacific Loons are evenly distributed along the Pacific coast of the U. S. but most winter off Mexico and both coasts of Baja California. They prefer marine water beyond the kelp line but are also fond of bays, estuaries, and lagoon channels (Russell).
In the past fishermen in areas near Japan noticed that Pacific Loons fished cooperatively and used this knowledge to enhance their own fishing. Loons foraging on Pacific sand lance during strong tidal situations concentrated the fish in a small area where they were also preyed upon by sea breams, which the fisherman targeted as their primary catch. “For their role in fishing, loons were worshipped as messengers from heaven” (Russell).
POPULATION STABLE BUT BEARS WATCHING
The population of Pacific Loons appear stable although accurate numbers for these birds are difficult to obtain. They are “vulnerable from oil spills although casualties have been low or nonexistent in most events documented to date” (Russell). In the area around Prudhoe Bay, Alaska oil fields new bodies of water are created due to impoundment beside gravel roads and pads. Pacific Loons have used these areas to breed successfully. A 1996 study noted that 34% of 123 Pacific Loon nests were located on artificial impoundments (Russell).
References available upon request from email@example.com.