Are American White Pelicans rare?

The American White Pelican is a large waterbird that breeds in inland lakes and rivers across North America. With their bright white plumage, large bill, and huge wingspan, American White Pelicans are a striking sight wherever they occur. But just how common or rare are these iconic birds?

American White Pelicans are widespread across North America, but their populations can fluctuate dramatically between breeding seasons depending on water conditions in their breeding habitats. In some years, tens of thousands of breeding pairs may nest across the continent. In other years, their numbers crash as breeding sites dry up. So while American White Pelicans as a species are not necessarily rare, their populations are dynamic and they may be scarce regionally in some years.

American White Pelican Range and Population

The American White Pelican breeds primarily in interior wetlands of central North America. Their range stretches from central California to Minnesota and Louisiana in the United States, and through much of western Canada. Outside of the breeding season, American White Pelicans may wander widely across North America in search of food.

According to the North American Breeding Bird Survey, there are an estimated 136,000 American White Pelicans across their range. However, as a colonial nesting species, their populations are not evenly distributed. Breeding typically occurs in colonies ranging from just a few to thousands of pairs. The largest colony may hold over 30,000 nests in a given year. So while American White Pelicans number in the tens of thousands, most individuals nest in just a handful of very large colonies.

The United States Fish and Wildlife Service periodically conducts more detailed surveys of American White Pelican colonies. The most recent survey in 2016 tallied about 70,000 adults across 53 colonies. This was down 60% from a similar survey in 2005 and indicates a substantial population decline over the past decade. Reasons for the decline are unclear but may relate to habitat loss, disease, disturbance, and other factors. So while still numbering in the tens of thousands, American White Pelican populations do appear to be decreasing from historic levels based on recent surveys.

Regional Status

American White Pelicans may be most abundant in their core breeding range of the northern Great Plains and western North America. Major colonies occur at locations like Chase Lake National Wildlife Refuge in North Dakota, Marsh Lake in Minnesota, and Stum Lake in British Columbia. Each of these sites may host 7,000-15,000 nests in a given year.

On the other hand, American White Pelicans are much rarer and local in the southern and eastern portions of their range. In Louisiana, breeding typically occurs only at two locations—Lacassine National Wildlife Refuge and Rabbit Island in Catahoula Lake. Combined, these colonies may have just 1,500-3,000 nests per year. And in the Carolinas along the Atlantic Coast, breeding is irregular and typically involves fewer than 100 nests. So while American White Pelicans can be abundant at prime breeding sites in the northern Great Plains, their populations are relatively small and localized in other parts of their range.

Seasonal Abundance

The abundance of American White Pelicans also varies dramatically by season. During the breeding period from April to August, most of the population is concentrated at colony sites and the surrounding wetlands used for foraging. But outside of breeding, American White Pelicans disperse widely across the southern United States and Mexico.

For example, National Audubon’s Christmas Bird Counts record only around 2,000 American White Pelicans across the country in December and January. But by summertime, counts at individual colonies can tally 10,000-30,000 adults. So the pelican’s abundance swings wildly between the breeding season, when most gather at colonies, and the nonbreeding season, when the population disperses across a much broader region. Their rarity or abundance may depend simply on what time of year you are looking for American White Pelicans.

Population Threats and Conservation

While still numbering in the tens of thousands, American White Pelicans have undergone population declines over the past few decades based on survey data. These declines likely relate to several key threats:

– Habitat loss – Draining of wetlands and altering of river flows removes crucial breeding and foraging habitat. For example, the pelican population crash at Chase Lake National Wildlife Refuge in the 2000s coincided with drought-related habitat loss.

– Disease – Several disease outbreaks have impacted American White Pelican colonies, including Type C botulism, West Nile virus, and Newcastle disease. In 2013, a botulism outbreak killed over 5,000 adult and juvenile pelicans at nesting colonies.

– Disturbance – Pelican colonies are highly sensitive to human disturbance, which can cause nest abandonment and reproductive failure. Disturbance from recreation, natural resource extraction, and other activities remains a threat.

– Environmental contaminants – American White Pelicans are vulnerable to many pollutants that accumulate in aquatic food webs. Potential impacts range from eggshell thinning to impaired reproduction and development.

– Food web changes – As lakes experience eutrophication or the fish community changes, American White Pelicans may lose access to sufficient food resources to successfully breed.

To combat these threats, protections have been implemented at key breeding colonies. Many sites are now protected as national wildlife refuges or provincial parks with access restrictions during breeding. Conservationists also work to manage water flows and restore lost wetland habitats across the pelican’s range. But despite protections, American White Pelican populations remain vulnerable to future habitat loss, disease outbreaks, human disturbance, and bioaccumulated pollutants. Their long-term population trends will depend on continued and expanded conservation efforts across North America.

Conclusion

In conclusion, while American White Pelicans remain common and widespread across North America, their populations are dynamic, uneven, and have undergone declines in recent decades. Tens of thousands of adults still nest each year, but these are concentrated into relatively few huge colonies that are highly vulnerable to environmental fluctuations and disturbance. Pelican numbers also shift dramatically between the breeding and nonbreeding season as the population contracts and disperses. While locally abundant at prime breeding sites in summer, American White Pelicans are rather scarce across much of their range during winter. And although conservation measures have been implemented, American White Pelicans still face multiple ongoing threats including habitat loss, disease, pollution, and food web changes. Their long-term population trajectory likely depends on expanding crucial wetland protections and proactively managing breeding sites across North America. So while American White Pelicans remain common in some measures, their populations are prone to substantial fluctuations, face significant conservation threats, and have declined markedly in recent surveys. They should not necessarily be considered rare, but their numbers and distribution warrant continued monitoring and protection efforts.

American White Pelican Population Data

Population estimates from periodic surveys by the U.S. Fish and Wildlife Service. The surveys indicate a substantial population decline between 2005 and 2016.