Basis for Listing

The American white pelican is distributed across the interior of western North America. The species experienced a decline in the 1970s to an overall population size of around 62,000 birds. In the 1980s, the total North American population increased to an estimated 150,000 birds. However, these birds congregate to breed in a limited number of significant colonies: 50 in Canada and only 18 in the United States (NatureServe 2008). Although colonies have remained stable or increased in the eastern part of the white pelican's range, there have been major population declines in the far western states. In the 1980s, only five colonies were found in an area that previously supported 23. Fluctuating water levels have been cited as the principal cause of the decline. The species has been on the National Audubon Society's Blue List since 1972, and some ornithologists have proposed that it be considered threatened under the federal Endangered Species Act.

The American white pelican formerly ranged throughout much of Minnesota, with nesting documented as far east as Aitkin County in 1904. The species declined in the late 19th and early 20th centuries, largely due to human persecution (Wires et al. 2005). There were no reports of nesting in the state after 1878 (Roberts 1932) until 70 nests were found at Marsh Lake in Big Stone and Lac qui Parle counties in 1968. Nesting was limited to less than 10 colonies in the early 1980s, and the species was subsequently listed as special concern in 1984. In the 1990s, nesting was confirmed in several additional areas. Large numbers of non-breeding adults are also regularly seen on other Minnesota lakes throughout the summer. Although there is evidence of an increasing population in Minnesota, it might best be viewed as a recolonization of its former range (Wires et al. 2005). Colonial breeding habits and occupancy of a small number of breeding sites make white pelicans particularly vulnerable to decline, meriting special concern status. The Marsh Lake colony is the largest known colony in North America, giving it continent-wide significance (Wires et al. 2005).

  Description

The American white pelican is one of Minnesota's largest birds, with a length of 1.2-1.8 m (3.9-5.9 ft.) and a wingspan of 2.4-2.9 m (7.8-9.5 ft.). The bird's size, white plumage, black wing tips and outer secondaries, and large, orange bill distinguish it from any other species. Although the pelican is awkward on land, it is graceful in flight.

  Habitat

The American white pelican selects large, shallow bodies of water that are rich in fish, in both treeless and forested areas. Nesting sites are usually on a flat, bare island, isolated from predators and human disturbance.

  Biology / Life History

The American white pelican is a short- to middle-distance migrant, with the exception of some year-round resident colonies in Texas and Mexico. Migration is triggered as lakes and rivers freeze in the breeding range. Wintering grounds for the species include the Gulf of Mexico, for pelicans which nest east of the Rockies, and the coastlines of California and western Mexico, for pelicans which nest west of the Rockies. Flocks of American white pelicans migrate together in formations. Pelicans are also gregarious when breeding, foraging, and loafing (Evans and Knopf 1993).

In their breeding territory, pelicans forage at lakes, marshes, or rivers that may be over 50 km (31 mi.) from their nesting islands. American white pelicans prefer to forage for fish, their main food, in shallow water and commonly practice cooperative foraging. To do this, they gather in a line, flap their wings, and synchronize bill dipping to drive fish toward the shallows or other areas where the fish are more easily caught. They may also steal fish from gulls, cormorants (Phalacrocorax spp.), or other pelicans. Typically, American white pelicans eat "rough" fish of little commercial value (Evans and Knopf 1993).

American while pelicans are a monogamous species, and most likely pair each year on their breeding grounds. Adults begin breeding when three years old. They perform a variety of flying and walking courtship displays, and select a nest site within a dense colony. Colonies are mainly located on isolated islands, also occupied by gulls and cormorants. A pelican colony can consist of thousands of birds (Evans and Knopf 1993). After courtship, each pair builds a nest by scraping gravel, soil, or vegetation to form a shallow depression. The bottom of the nest may contain little or no insulation. A clutch of two eggs is common. Both males and females take turns to continuously incubate and guard the eggs until they hatch, usually about 30 days later. The young are altricial. The first chick to hatch frequently harasses the younger sibling, causing it to leave the nest early or move to an area of the nest where it is fed less often. Second chicks often die of starvation, predation, or exposure. Adults feed chicks by regurgitating food into their beak pouch, where it is made accessible to the chicks. Parents continuously brood nestlings for about 17-25 days. As parents begin leaving nests unattended, groups of chicks huddle together for warmth, forming a pod or creche. These pods may also serve as protection from predators (Evans and Knopf 1993). The young walk from the nest at about 26 days, and fly after 62-63 days.

  Conservation / Management

Destruction of breeding and foraging habitat, as well as human disturbance, are considered the most important limiting factors for American white pelican populations (Evans and Knopf 1993). Human disturbance is a common cause of colony desertion by white pelicans, particularly during courtship and at the beginning of incubation. During later incubation and brooding, adults may leave eggs or young unattended if disturbed, resulting in their greater exposure to storms, temperature fluctuations, or predation by gulls. Common agents of disturbance include motorboats and low-flying planes. People may also harass or kill pelicans if they believe, incorrectly, that pelicans eat game fish (white pelicans eat mainly "rough" fish). Disturbance to pelicans may also occur as people try to eliminate double-crested cormorants (Phalacrocorax auritus ) from an area. Studies or censuses on American white pelicans should be conducted from a distance whenever possible, using blinds and aircraft. Research within colonies should be minimized and conducted during fair weather with moderate temperatures. Public education and enforcement of migratory bird protection laws are necessary to protect breeding colonies (Evans and Knopf 1993). Flooding and drainage are also a concern for this species. High water can destroy pelican nests, while lower water levels may allow mammalian predators greater access to islands used for nesting. Fluctuating water levels may also destroy foraging habitat.

  Conservation Efforts in Minnesota

In the 1980s, nesting of American white pelicans was limited to just two sites in the state. Population estimates were approximately 1,000 pairs on Marsh Lake in Lac qui Parle and Big Stone counties (1986) and 25-50 pairs on Crowduck Island in Lake of the Woods County (1983). The Marsh Lake American white pelican colony had grown steadily from the initial 65-75 pairs present in 1968. A statewide survey of white pelicans was conducted in 2004 as a collaborative effort between the Minnesota DNR and the University of Minnesota with funding from the State Wildlife Grant Program. Pelicans were found to be nesting at 16 sites, three of which had not previously been known. The number of nesting pairs statewide was estimated to be 15,824, with more than 13,000 of those nesting in the Marsh Lake complex in Big Stone and Lac qui Parle counties (Wires et al. 2005). Other large colonies were found at Minnesota Lake in Faribault County, at Lake of the Woods, and at Red Lake in Beltrami County. Only one historic site, Pelican Lake in Wright County was inactive, apparently because of high water levels. Non-breeding birds were also observed in most western counties. The large number of non-breeders may have included birds dispersing from the Chase Lake colony in North Dakota, which was abandoned during the 2004 breeding season.

Known colonies should be censused about every three years, with an emphasis on determining reproductive success. Monitoring at the Marsh Lake complex is particularly important because of its continental significance, but aerial surveys are recommended to avoid disturbance. Other important colonies for monitoring are Lake of the Woods, Minnesota Lake, Red Lake, and Pigeon Lake. Ground surveys of these colonies can be conducted if the following conditions are met: gulls are not present, visits are less than one hour, nesting is well underway but chicks are not yet mobile, and weather is mild (Wires et al. 2005). Marsh Lake, Pigeon Lake, Lake Johanna, Leech Lake, and Lake of the Woods colonies have been nominated as Important Bird Areas, a program of the National Audubon Society. Additional protection should be sought for all nesting islands and other American white pelican breeding and foraging areas.

  References and Additional Information

Evans, R. M., and F. L. Knopf. 1993. American White Pelican (Pelecanus erythrorhynchos). Number 57 in A. Poole and F. Gill, editors. The birds of North America. The Birds of North America, Inc., Philadelphia, Pennsylvania.

NatureServe. 2008. NatureServe Explorer: An online encyclopedia of life [web application]. Version 7.0. NatureServe, Arlington, Virginia. . Accessed 9 June 2008.

Roberts, T. S. 1932. The birds of Minnesota. Volume 1. University of Minnesota Press, Minneapolis, Minnesota. 691 pp.

Wires, L. R., K. V. Haws, and F. J. Cuthbert. 2005. The Double-crested Cormorant and American White Pelican in Minnesota: a statewide status assessment. Final report submitted to the Nongame Wildlife Program, Minnesota Department of Natural Resources. 28 pp.