Pelecanus erythrorhynchos

Large nesting and winter range in Canada, United States, and Mexico; several dozen colonies include more than 60,000 nesting pairs; population has increased greatly since the 1960s; highly vulnerable to disturbance; habitat protection remains a concern, as does increased incidence and severity of disease.

Nesting occurs locally in south-central British Columbia, Alberta, Saskatchewan, Manitoba, and southwestern Ontario south through northern California, Nevada, Utah, Colorado, South Dakota, and Minnesota; also on the central coast of Texas and sporadically in east-central Mexico (Tamaulipas) and central Durango, Mexico (Johnsgard 1993, Knopf and Evans 2004). During the nonbreeding season the range includes Florida, Gulf of Mexico coast south to northern Yucatan Peninsula, and central California south to southern Baja California and through western mainland Mexico to Nicaragua (AOU 1983, Knopf and Evans 2004). In North America, the highest winter density occurs in southern Texas (Root 1988); other important areas include the Gulf coast and Everglades region of Florida. In summer, white pelicans sometimes wander north of the usual range.

Coded range extent refers to breeding range.

Breeding occurrences include at least 27 colonies east of the Continental Divide and 15 west of the Divide; several additional colonies likely exist but have not been recently documented (King and Anderson 2005).

This species is highly sensitive to human intrusion into breeding colonies, which cause desertions and exposure of eggs and young to temperature extremes and gull predation (Knopf and Evans 2004). Loud and close passes by motor boats and low flying airplanes can cause bird to flee from nesting colonies or feeding or roosting areas (Knopf and Evans 2004).

Hydrological alterations by humans have resulted in a net loss of breeding and feeding areas (Murphy 2005), and these alterations remain an important potential limiting factor (Knopf and Evans 2004). Some hydrological changes have created or improved nesting habitat.

Diseases (particularly Type C botulism and West Nile virus) have caused significant die-offs and mortality in recent years and are a cause for concern (Rocke et al. 2005).

In some areas, pelicans fly long distances (hundreds of kilometers) from nesting areas to the closest suitable feeding areas, but may nevertheless breed successfully.

Ehrlich et al. (1992) noted that several nesting colonies were jeopardized by several consecutive years of drought, which may lower water levels and allow mammal predators (particularly coyote and raccoon) access to pelican breeding sites.

Shooting historically was a significant mortality factor and still is the greatest mortality factor resulting in band returns (Evans and Knopf 1993).

After the 1960s, hundreds of pelicans died yearly due to the ingestion of insecticides such as toxaphene, endrin, and dieldrin, and as recently as winter 1998-99, 800 American white pelicans died in Florida from poisoning by insecticides that were resuspended from flooded agricultural soils (Keith 2005). However, pesticides and mercury currently are not regarded as significant causes of reproductive failure or population decline (see Knopf and Evans 2004). However, there is concern that increased incidence and severity of disease in pelicans may be related to pesticide contamination (Murphy 2005).