In 1970, under a law that preceded the Endangered Species Act of 1973, the U.S. Fish and Wildlife Service listed the brown pelican as endangered. A recovery plan was published in 1983. Currently, the pelican is proposed for delisting.

Historical Status and Current Trends

There are two geographically and genetically distinct regional populations, or subspecies, of brown pelican that occur in North America. They are the California brown pelican (P. o. californicus), ranging from California to Chile, and the eastern brown pelican (P. o. carolinensis), which occurs along the Atlantic and Gulf coasts, the Caribbean, and the Central and South American coasts. Consumption of pesticide-laden fish, lack of food, and disturbances by humans were responsible for a marked decline in reproductive success, and consequently a decline in numbers of both brown pelican subspecies in the 1960s and 1970s. The eastern brown pelican remains endangered in Mississippi, Louisiana, Texas, Central and South America and the West Indies, but has been removed from the list in Alabama, Florida, Georgia, South Carolina, and North Carolina. Current information indicates that the California brown pelican has sufficiently recovered as a result of restrictions on the use of certain types of pesticides (organochlorines), and this news has prompted a proposal to delist this subspecies. A final ruling on this action is pending.

Habitat

The brown pelican is a warm weather species that thrives near coasts and on islands. The California brown pelican generally uses the rocky islands along the California coast for their group, or "colonial," nest sites. These islands typically feature steep, rocky slopes with little vegetation, and they must be without terrestrial predators or human disturbances. Nearby high quality marine habitat is also essential. Brown pelicans rely in part on the actions of marine predators such as sharks, salmon, and dolphins to force schools of fish to the surface where the pelicans can catch them. Pelicans will breed only in areas with enough food to support the breeding colony. Roosting and resting, or "loafing," sites where brown pelicans can dry their feathers and rest without disturbance are also important.

Life History

Brown pelicans build large, bulky nests on the ground or in bushes and lay an average of three eggs, which the parents take turns incubating. After 30 days, the eggs hatch and the helpless young require constant warmth and attention for several weeks afterwards. At about 12 to 13 weeks of age, when they are able to fly, the young are left to fend for themselves. Unskilled at obtaining food, many young pelicans don't survive this period. Juvenile birds typically leave the home colony and begin to reproduce at about two years of age. Pelicans are known to live for approximately 30 years, but the average may be much less than that due to predation, disease, starvation, etc.

Reasons for Decline

Brown pelicans received severe exposure to DDT and other contaminants through consumption of contaminated fish. As was the case with many birds, this exposure resulted in the production of eggs with thin eggshells that were unable to withstand the weight of the parent during incubation, resulting in crushed eggs instead of healthy chicks. As a consequence, the number of chicks produced each year declined dramatically, and the population was severely reduced.

Other factors, including local food shortages and human disturbance, also contributed to the decline of the species. Pelicans require undisturbed habitat and abundant supplies of fish, particularly during the breeding season. If nesting pelicans are startled while on the nest, their abrupt departure often crushes their eggs. If sufficient food supplies are not readily available, pelicans will abandon breeding colonies. Factors contributing to decreased food availability include commercial fishing and naturally-occurring increases in ocean water temperature.

Conservation Measures

In the early 1970s, the use of DDT was banned, and restrictions controlling the use of other pesticides were imposed in the United States. As a result, pelican reproduction improved. Sanctuaries, reserves, and natural areas have been established to protect nesting habitat and fledging areas from human disturbances and to preserve nearby marine resources. Reduction of contaminant levels, habitat protection, and conservation of food resources have led to the successful recovery of the California brown pelican population to self-sustaining levels, warranting the current proposal for delisting of this subspecies.

References

U.S. Fish and Wildlife Service. 1983. California Brown Pelican Recovery Plan. Portland, Oregon. 179 pp.

USFWS, Washington, D.C. Species Account: Brown Pelican.