An Imperial Beach Hidden Gem And DigIB Bird Of The Week, The American White Pelican
Aug 06, 2020 02:42PM
By Paul Spear
This weekly column provides photos of birds photographed locally in the Tijuana Estuary or on IB's beaches along with background on the bird.
American White Pelican (Pelecanus erythrorhynchos)
This week’s “Bird of the Week” is the American White Pelican (Pelecanus erythrorhynchos), one of the largest birds in North America, with a 9-foot wingspan. They are similar to the Brown Pelican in shape but much larger, and very different in habits. They generally occur far inland, feeding cooperatively in shallow lakes, and not diving from the air for fish like Brown Pelicans. Despite its great size, they are spectacular fliers, with flocks often soaring very high in the air, ponderously wheeling and circling in unison. Their colonies are vulnerable to disturbance and habitat loss, with total populations declining through first half of 20th century, but with a substantial increase since the 1970s.
American White Pelicans inhabit lakes, marshes, and salt bays. In breeding season they move inland, nesting on isolated islands in lakes, and feeding on shallow lakes, rivers, and marshes. Feeding areas may be miles from their nesting sites. They also breed locally on coastal islands such as the Coronados. Flocks in migration stop on lakes, and rivers. In winter they inhabit mainly along the coast, on shallow, protected bays and estuaries, and also on large lakes in warm climates.
These white pelicans forage by swimming on the water surface, dipping bill into water and scooping up fish in their pouches. During breeding season they do much of their foraging at night, locating fish by touch during frequent dipping of bill, and by day, probably locating their prey visually. They sometimes forage cooperatively, lining up and driving fish toward shallower water. Their diet consists of mostly fish, primarily eating "rough" fish of little value to humans, crayfish, and salamanders.
Their bills are huge and flat on the top, with a large throat sac below, and, in the breeding season, this is vivid orange in color as is the iris, the bare skin around the eye, and the feet. In the breeding season, there is a laterally flattened "horn" on the upper bill, located about one-third the bill's length behind the tip. This is the only one of the eight species of pelican to have a bill "horn". The horn is shed after the birds have mated and laid their eggs. Outside the breeding season the bare parts become duller in color, with the naked facial skin yellow and the bill, pouch, and their feet an orangy-flesh color.
Apart from the difference in size, males and females look exactly alike. Immature birds have
light grey plumage with darker brownish nape and remiges. Their bare parts are dull grey. Chicks are naked at first, then grow white down feathers all over, before moulting to the immature plumage.
American White Pelicans are colonial breeders, with up to 5,000 pairs per site. The birds arrive on the breeding grounds in March or April. Nesting starts between early April and early June. The nest is a shallow depression scraped in the ground, in some twigs, sticks, reeds or similar debris have been gathered. After about one week of courtship and nest-building, the female lays usually 2 or 3 eggs, sometimes just 1, sometimes up to 6.
Both parents incubate for about one month. The young leave the nest 3–4 weeks after hatching. At this point, usually only one young per nest has survived. They spend the following month in a crèche or "pod", moulting into immature plumage and eventually learning to fly. After fledging, the parents care for their offspring some three more weeks, until the close family bond separates in late summer or early fall, and the birds gather in larger groups on rich feeding grounds in preparation for the migration to the winter quarters. They migrate south by September or October.
These huge white birds can be found near the river mouth in the Tijuana Estuary during the winter months, and are a joy to see. Look for this species and many others while walking our beaches and the great trails in the estuary. Happy birding!
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