Periodic Status Review for the American White Pelican in Washington (2016)
 
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Periodic Status Review for the American White Pelican in Washington (2016)

Category: Threatened and Endangered Species - Status Reports

Date Published: October 2016

Number of Pages: 30

Author(s): Derek W. Stinson

EXECUTIVE SUMMARY:

The American White Pelican (Pelecanus erythrorhynchos) is a large colonial nesting bird that eats mostly non-game fish, such as carp, suckers, and sticklebacks, as well as amphibians and crayfish. The species was listed as a state endangered species in Washington in 1981. They are not listed under the federal Endangered Species Act, but are protected under the Migratory Bird Treaty Act.

American White Pelican (or 'white pelican') numbers and range were reduced throughout the 19th and early 20th century due to habitat loss, persecution, and pesticide contaminants, especially DDT. In more recent decades, populations have recovered from pre-1970 declines; western colonies contained an estimated 42,692 breeding adults in 2014. Despite overall improved status, the white pelican remains a species of moderate conservation concern, primarily because of the concentration of birds on relatively few breeding colonies, and their vulnerability to disturbance, water level fluctuations, disease, and history of 'boom and bust' productivity.

Concurrent with range-wide increases, the numbers of American White Pelicans observed in Washington have increased substantially in the last 30 years. Historically, white pelicans bred in eastern Washington on Moses Lakes, and perhaps at Sprague Lake and a few other sites. There are no published records of nesting after 1926, but several hundred pelicans were seasonally on Moses Lake into the 1940s. In 1994, after an absence of breeding for ~50 years, a breeding colony was established in the Columbia River north of the mouth of the Walla Walla River. Since that time, the colony has grown steadily, and 3,118 white pelicans were counted in aerial photos in May 2016. In 2010, another colony formed on Miller Sands in Oregon waters of the Columbia River estuary. Aerial photographs from May 2016 contained 492 adults and 351 nests, but the colony was abandoned in June. Inland waters of eastern Washington also support significant numbers of non-breeding (1–2 year old) white pelicans, especially along the Columbia River from The Dalles to Chief Joseph Pool. During summer, up to 2,000 birds are observed in the Potholes region; smaller numbers remain in winter, but most winter in southern California.

Although white pelicans eat mostly carp and suckers, they sometimes consume fish resources that are of conservation concern or have recreational value. White pelicans are large conspicuous birds that have increased in number and many observers assume they are impacting salmonid runs. However, based on smolt PIT tag detections, the pelicans nesting at Badger Island and Miller Sands, do not seem to be an important source of mortality for out-migrating juvenile salmonids in the Columbia and Snake rivers. There is some evidence that impacts on salmonids may be more significant at certain times and places in tributaries such as the Yakima River.

Although white pelicans have recovered substantially, populations remain somewhat vulnerable and Washington still only hosts a single colony. White pelicans are highly sensitive if disturbed by humans or predators on breeding colonies and prone to desert or leave eggs and young exposed to predation. Other factors affecting white pelican populations include diseases, severe weather, and loss of breeding and foraging habitats due to water level changes.

Given the increase in numbers and the new colony in the Columbia River estuary, the white pelican may no longer fit the definition of endangered in Washington, as defined in WAC 232-12- 297: Endangered species are, "seriously threatened with extinction throughout all or a significant portion of its range within the state." It is recommended that the American White Pelican be down-listed to state threatened in Washington. A threatened species is, "likely to become an endangered species within the foreseeable future throughout a significant portion of its range within the state without cooperative management or removal of threats."

Suggested Citation:
Stinson, D. W. 2016. Periodic status review for the American White Pelican in Washington. Washington Department of Fish and Wildlife, Olympia, Washington. 22+iv pp.