WHITE PELICAN—ANOTHER SUCCESS STORY

Just as happened with their cousins the Brown Pelicans, American White Pelican populations fluctuated greatly during the 20^th Century. Having bred at Moses Lake and probably Sprague Lake in the interior of Washington early in the century, by the middle of it they had disappeared from the state as a breeding bird.

As the second half of the century crept along, these pelicans remained in the state as nonbreeding visitors, sometimes as many as hundreds of them at fish-rich lakes of the Columbia Basin. Oddly, there is no evidence that American White Pelicans suffered from DDT poisoning as did North American Brown Pelicans. So there must have been other reasons for a general decline in their populations, and human disturbance of breeding colonies is considered a very likely factor.

However, late in the century a turn-around was observed, and White Pelican populations began to increase all across the range of the species. In the 1990s, a few breeding colonies were discovered along the Columbia River in the Tri-Cities area. The primary one now is on Badger Island in McNary National Wildlife Refuge, where as many as 1,000 pairs have bred. An injured flightless Bald Eagle spent the summer of 2013 there, and the pelican population may have suffered from that.

In 2010, a small colony formed on Miller Sands Spit, in the Lower Columbia River, reaching a few hundred pairs by 2012. The Army Corp of Engineers covered the nesting area with dredge spoil that fall, but small numbers continued to be seen the next summer.

A great number of nonbreeding birds, up to a few thousand, occur in the state every summer along the Columbia River and some of its tributaries. It would have been unheard of to see White Pelicans in the Yakima River 20 years ago, but now they feed all along its length. Small numbers even spend the winter along the Lower Columbia River, something never observed before the last few years.

The species has increased all over the continent in recent years. Counts made in 1998-2001 totaled about twice as many birds as in 1979-1981. Those counts, now 15 years old, estimated over 150,000 birds, a respectable number of individuals for a very large bird such as this. And the estimate is conservative, as some known colonies were not surveyed. Further surveys are to be carried out.

Brown Pelicans and their close relative Peruvian Pelicans are both confined to the marine environment. They forage by flying, often in small flocks, well above the water surface and diving into it when prey are sighted. American White Pelicans, on the other hand, feed like other species of pelicans all over the world.

American White Pelicans spend much time on fresh water, although they are equally at home on salt water, and large numbers winter coastally. When foraging, several birds move through shallow water, dipping the bill in the water rapidly to capture nearby fish. Sometimes a whole line of birds forms and moves forward steadily, individuals dipping their bills one after another as they herd schools of fishes ahead of them.

Like gulls and other fish-eating birds, they also collect at dam spillways where their prey is delivered to them, often too stunned to escape. Dams are usually not good for fish but often good for birds!

Dennis Paulson

CASPIAN TERNS – FABULOUS BIRDS BUT NOT ALWAYS APPRECIATED

The Caspian Tern (Hydroprogne caspia) is the largest of the world’s terns and one of the most widely distributed. The size of a medium-sized gull, it is a most impressive bird, with its striking silvery-white plumage, black crown, and big red bill. Its vocalizations are no less impressive, a loud rasping call that one could imagine pterodactyls made on their breeding grounds.

Caspian Terns breed on islands in lakes or bays, usually in colonies of hundreds to thousands of birds. The largest Pacific Northwest colony is on East Sand Island, at the mouth of the Columbia River, with about 10,000 pairs. This may be the largest colony in the world. The first eggs are laid in mid April, the first hatching about a month later and the first fledging about a month after that. Thousands of birds are still present in late July, but the colony empties shortly after that.

Most pairs lay three eggs, and when they hatch both adults are kept busy bringing in fish from surrounding waters. They fly well above the water, up to 10 meters or more, and dive when they see a fish near the surface, submerging their body completely. If they succeed, they head for the colony. The young have a high-pitched call, like most young birds, and in and around a colony the constant calling back and forth between parents and offspring brings to light the meaning of the word “cacophony.”

Terns are all fish-eaters, and big colonies of Caspians can only thrive where there are a lot of fish in the nearby waters. The Lower Columbia River is such a place, rich in many kinds of fish at the transition from fresh to salt water. Among them are salmon of several species. After their early growth in fresh water, salmonid smolts descend the river to spend some years in salt water before returning to spawn. It has been estimated that 100 million smolts come downriver each year, most of them released from hatcheries.

The terns, and other fish-eating birds nesting in the same area, are there to receive them. It has also been estimated that the tern colony on East Sand Island accounts for predation on about 5 million of these smolts. Although this is only 5% of the estimated smolt run, it is enough to greatly concern wildlife management personnel in both Washington and Oregon.

In fact, concern seems sufficiently great that the terns have been systematically persecuted. Over the past few decades, Caspian Tern colonies have formed at numerous sites along the Washington coast, and at each of them the birds have been hazed until the colony disbanded. Because they have been chased away from islands, they have tried to nest on rooftops and other humanmade structures, but each time they are discovered, they are soon displaced.

Because a few of the colonies on Columbia River islands are thriving, there are enough excess terns that they are still to be seen and heard flying over all of our coastal waters, but many of them fail to breed because they are not allowed to. Salmonid fishes are of great importance to the Pacific Northwest economy, and Caspian Terns are not; the equation does not favor the terns.

POSTSCRIPT (added 23 June 2011)

The largest PNW tern colony, on Sand Island at the mouth of the Columbia, has been severely disrupted by predators, especially Bald Eagles, and will probably fail this year. Fortunately, the terns are long-lived and will presumably breed next year, but the eagles are proving to be real villains in this case, disrupting colonies of terns and other seabirds severely enough that they pose a long-term threat to the populations of these birds. Anthropogenic changes may have made the situation worse, with a decline in other eagle prey and a reduction of the seabird colonies to few sites.

Dennis Paulson