In Utah, the only known breeding colonies of the American White Pelican, Pelecanus erythrorhynchos, are located in the northern portions of the state, specifically within the Utah Lake/Great Salt Lake ecological complex. There is a record of pelicans nesting on Rock Island, Utah Lake in 1904 (Goodwin 1904) and two records of pelicans nesting in greasewood hummocks southwest of Farmington Bay WMA in 1973 and 1974 (C. Jensen, pers. comm.). Historically, pelicans were identified as nesting on Egg Island in 1850 by Howard Stansbury and perhaps on Badger Island in the 1880s (Dr. H. A. Whytock). Beyond these records, the majority of nesting has taken place on Hat Island and Gunnison Island. Pelicans have not nested on Hat Island for several decades. Gunnison Island persists as the only colonial nesting site for American white pelicans in Utah and currently ranks as one of the largest breeding colonies in North America. During spring migration, the breeding season, and fall staging and migration periods, American White Pelicans can be observed at many reservoirs throughout the state.

American White Pelicans migrate from northern breeding areas, but are year round residents in Texas (Chapman 1988) and Mexico. Populations breeding west of the Rocky Mountains move southwest into California and due south to the west coast and central states of Mexico (Behle 1958). Spring returns occur in late February in Nevada and in early March in Utah (Behle 1959, Alcorn 1943). Further north in Yellowstone and Canada, birds arrive in April and May (Diem 1967).

Autumnal departure seems to be drawn out from October through December. In Utah, at least three factors seem to play a role when birds depart: 1) the opening of the fall waterfowl hunting season, 2) availability of fisheries, 3) and ice up. Behle recorded banded birds from the Great Salt Lake being recovered north in Idaho (1958). Recent satellite telemetry studies of pelicans radio tagged at Pyramid Lake, Nevada also suggest that some birds fly north after the breeding season to the Intermountain area. One bird made a flight from Pyramid Lake to Bear River Bay, Utah in the course of a day (Fuller et al. 1998).

The primary food is fish. Fish are often sought in water less than 2.5 m deep (Anderson 1991). American White Pelicans are diurnal and nocturnal foragers. Capture rates are higher during day and at the leading edge of foraging flocks, than at night (McMahon and Evans 1992a). Cooperative foraging is often employed in shallow water. Several to hundreds of pelicans can be observed to not only cooperate but also coordinate strategies to capture fish. They drive fish to shallows and often encircle and concentrate prey, then dip their bills into the water and scoop fish into their gular pouches (for details see Anderson 1991, McMahon and Evans 1992b). They forage mainly on "rough" fish, which are often small (less than one-half bill length).

The breeding range of American White Pelicans extends from the park lands and prairies of Canada into the mountain states, to the Gulf Coast of Texas and Mexico. Preferred nesting habitats are islands, especially those associated with fresh water lakes. Preferred foraging areas are shallow lakes, marshlands, and rivers. Breeding colonies are often 50+ km from foraging areas. Low site fidelity and high mobility appear to be adaptations American White Pelicans have made to take advantage of temporarily rich food supplies (Evans 1972, Knopf 1976).

American White Pelicans are highly social. Nesting in colonies, using cooperative flight and foraging strategies, pelicans are among the most gregarious of avian species. These birds are often observed sleeping, roosting, and sun bathing together. They are monogamous. Pair formation occurs after arrival in Utah the last week in March (Knopf 1979). Nest building occurs in less than 5 days. For the colony as a whole, nest initiation extends over 3 months in Utah (Knopf 1979). A two egg clutch is produced within a week of nest completion, with an incubation period of 30 days. Nestling attendance by a parent occurs to 3 weeks of age, after which time young congregate into pods. Young from various sub-colonies often combine to form larger pods.