Front Cover: August 2019

American White Pelican by Edgar Allan Slothman

August 1, 2019 4 MIN READ Feature Articles, Front Cover

American White Pelican

The American White Pelican (Pelecanus erythrorhynchos) is a spectacular bird; a flock of these pelicans flying or soaring is a sight to remember. They alternately flap and glide in a synchronous manner, and usually fly in a long line, often in a V formation at the front. Flocks also soar on sunny days, sometimes to great heights. They are highly gregarious while nesting, foraging, loafing, and during migration.

American White Pelicans (White Pelicans) are unmistakable among North American birds. They are large and white-bodied with black primaries and outer secondaries that are in sharp contrast in flight to the white body and the rest of the wings. The bill is huge and bright orange as are the legs and feet. In the breeding season, adults also develop a conspicuous horny, plate-like structure on the top of the bill. Juvenile birds are similar to adults in appearance, but are tinged light gray on the wings and neck. White Pelicans show little or no geographic variation and no subspecies have been described.

DNA studies have thrown the Pelicaniformes into a muddle, suggesting that the Pelicanidae, which includes all of the world's pelicans, is more closely related to the New World vultures and storks than to other members of the former Pelicaniformes such as the frigatebirds, gannets, and cormorants. Sibley and Alquist's DNA studies (1990) led them to group the Pelicaniformes with the grebes, ibises, spoonbills, New World vultures, storks, penguins, albatrosses, and petrels to form the huge order Ciconiiformes. Subsequent studies however have reshuffled the families and orders to group the Pelicanidae with the herons, ibises and spoonbills, and two African single-species families: the Hamerkop (Scopidae) and the Shoebill (Balaenicipitidae). How's that for confusing? These nomenclatural problems are not settled and clearly need to be further sorted out.

White Pelicans breed in scattered colonies across southwest Canada and the northwestern quadrant of the United States as far south as northern California and Colorado. They are migratory except for a year-round colony in Texas and two in Mexico. They winter from California and western Arizona south along the coast to Baja California and El Salvador, or from west Texas east to Florida and south through central and eastern Mexico to the Yucatan. In Massachusetts, up to the middle of the twentieth century American White pelicans were rare, with only a handful of reports. In recent decades however, sightings have been nearly annual along the coast, particularly on Cape Cod and the Islands and at Plum Island on the North Shore.

White Pelicans are monogamous colonial breeders. Courtship and pairing occurs several weeks after arrival on the breeding grounds, which are mostly on low-lying islands. Courtship flights may follow or precede birds strutting single file with heads erect and bills down. Courtship displays include bowing with neck arched, wings elevated at the shoulders, pouch extended, and head swaying. They are generally silent even during courtship. Groups of newly-paired pelicans select a territory and nest site near other birds at the same stage of the nesting cycle, creating dense synchronized subcolonies that form the greater colony. Pelicans are territorial in the immediate vicinity of their nest, which both birds defend with bill jabbing; they give threat displays with head and bill forward, sometimes with the bill pouch extended ventrally. White Pelicans often share nesting islands with cormorants, gulls, and other birds.

The nests are usually on flat or gently sloping surfaces on the breeding island, usually in sparse vegetation, but occasionally among bushes or trees. The nest is a shallow depression with a rim of gravel or vegetation. Neither parent develops a brood patch, but both incubate the clutch of two chalky white eggs by covering them with the webs between their toes. Incubating birds may extend wings, probably for cooling, and may also flutter the gular pouch to aid in evaporative cooling. The young hatch in about one month. Their eyes are closed for the first day and they are naked, and although they can raise their heads, they are helpless. The chick that hatches first is usually more aggressive, gets most of the food, attacks and pecks the second chick, and drives it to the edge of the nest where it usually starves to death, a victim of siblicide. The surviving chick usually stays in the nest for two to three weeks. When the parents of a sub-colony begin to leave the nests unattended, the chicks wander and form crèches, where all of the young from the colony stay for about a month. Initially, young birds may leave the crèche to be brooded by the parents at night. The parents feed the chicks by regurgitating small fish. As chicks get older, they feed directly from the adult's pouch and eventually feed by reaching down the parent's throat. Both parents continue to feed the surviving chick until it leaves the colony after 10–11 weeks, about a week after its first flight.

White Pelicans feed mostly on fish that range in size from small schooling fish to large bottom feeders. While swimming or floating, they forage in shallow water by dipping their long bills into the water and scooping up fish in their large, flexible pouches. They raise their bills to facilitate swallowing. They are generally diurnal foragers, locating prey by sight, but also forage at night during the breeding season, when tactile location of prey becomes important. They often forage cooperatively, with flocks using coordinated movements, sometimes swimming and circling schools of fish or driving them into shallow water with bills dipping and wings flapping. They often synchronize their bill dipping. They never forage by plunge-diving as Brown Pelicans do.

Nesting White Pelicans are preyed upon by foxes and coyotes, nests are raided by gulls, and young are taken by hawks, eagles, and owls. Human disturbance can be a major problem, often causing colony abandonment. Nesting birds, for example, are often dispersed by the close approach of motorboats. When a disturbed adult leaves the nest, it may result in gull predation or, in hot weather, heat-related damage to eggs or chicks. Habitat loss is also a problem. White Pelican populations declined through the 1950s but have subsequently increased. Protective legislation and public awareness have helped to stabilize White Pelican populations, so there is hope for the continued presence of this most interesting species.

William E. Davis, Jr.