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

BROWN PELICANS IN WASHINGTON

When I moved to Washington in 1967, Brown Pelicans were rare in the state. Formerly common and widespread on all coasts of the US, their populations had crashed over a period of decades. Only after some time and much research did the cause become clear. Beginning soon after the Second World War, DDT was developed as the first of the modern synthetic pesticides. Within a short time, it had been liberally applied to crops all over the continent and to settled areas to combat the mosquitoes that transmitted diseases such as malaria.

DDT accumulates in tissues and becomes concentrated as it passes up the food chain. Fish picked it up from the water and passed it on to the pelicans that ate them, concentrating the chemical in pelicans more and more. One of its byproducts, DDE, interferes with calcium metabolism and as a consequence, the birds weren’t able to produce sufficient calcium for their eggshells. The thin-shelled eggs cracked when the adults attempted to incubate them, and reproductive success dropped precipitously all around our coasts.

The consequences of using this pesticide became so obvious that in 1972 the Environmental Protection Agency banned its use in the US. Fish took up less of it, eventually pelicans were pretty much free of it, and their nesting success improved greatly.

By the end of the 20^th Century, Brown Pelicans had become common again on the Pacific coast and were coming up to Northwest waters in numbers never seen before. Now thousands of them visit our outer coast every summer to take advantage of fish populations apparently greater than those around their breeding grounds in southern California and Mexico. A small number of birds make their way all the way down to southern Puget Sound, and a few even stay through the winter now.

Our pelicans are a good mixture of adult birds with white heads and dark underparts and juveniles with brown heads and white underparts. They roost in large flocks on sand islands, jetties and piers and launch into the air to feed after long sessions of resting and preening.

This unmistakable bird is an aerial plunge diver. Single pelicans, sometimes in groups, fly several meters above the water and, when they spot a fish or school of fish below, they fold their wings and drop like a plummet, piercing the water with their long bill and almost completely submerging. When the bill reaches one or more fish, it opens and water rushes into the huge pouch. The pelican lifts its head and lets the water drain out, keeping the fish inside to be swallowed.

Heermann’s Gulls, breeding in the Gulf of California, also move north along the Pacific coast, becoming common in Washington waters while the pelicans are here and then moving south again in late fall.

When a pelican dives, it may be accompanied by one or more of these kleptoparasitic gulls. If a fish falls out of a pelican pouch, a gull is often there to grab it.

Dennis Paulson

YAQUINA HEAD, PARADISE LOST?

The islands off Yaquina Head in Oregon have always been just right for nesting seabirds. Isolation from the mainland gives them safety from mammalian predators, a very important feature for colonial birds. Colonies of nesting birds would be sure to attract predators such as coyotes, foxes, raccoons, and other carnivorous mammals, but apparently most of these mammals are not inclined to swim to offshore islands, so birds that nest on these islands are relatively safe.

These are scenes from Yaquina Head on 6 May 2011. A great colony of Common Murres has been there for many years, occupying the tops of several of the islands. In addition, large numbers of Brandt’s Cormorants nest among the murres and on lower ledges, and Pelagic Cormorants and Pigeon Guillemots fill in other parts of the islands.

The colony was flourishing during our visit, probably several thousand murres and good numbers of the other species. But the colony faced threats like never before. Bald Eagles have continued to increase every year since the banning of DDT in North America, and they are proving very effective predators on colonial nesting birds. Once the birds began to lay eggs, eagles disturbed the colony daily, taking both adult and young murres as well as eggs, and the massive disturbances caused by their presence enabled crows, ravens and gulls to take additional eggs and young.

Unexpectedly, Brown Pelicans proved almost as great a threat. Immature birds, not old enough to return to breeding colonies, stayed at Yaquina Head through the summer and visited the murre colony regularly. Walking and flapping through the colony, they picked up dropped fish and then began picking up young birds to get them to disgorge their fish. If that wasn’t enough, they also began to swallow the chicks whole. Many more chicks fell from their nesting ledges and drowned in the surf. Further disturbance was caused by Turkey Vultures that visited the colony.

During 372 hours of monitoring the colony in 2011, observers from the Hatfield Marine Science Center recorded 186 disturbance events, during which 1034 eggs, 142 chicks, and 70 adult murres were taken. Depredation rates were three to ten times higher than in previous years. Researchers estimated that no more than 28% of murre pairs successfully raised chicks to fledging age. Cormorants, much more spread out and with larger chicks, appeared to suffer much less mortality.

Interestingly, not only Bald Eagles but also Brown Pelicans and Turkey Vultures are increasing in the Pacific Northwest in recent years, perhaps all as a result of the removal of DDT from the environment. A new balance may be struck as one set of species becomes less common as previously rare species increase. How will we protect the murres now that we have protected their predators?

Dennis Paulson