BIRMINGHAM, Ala. - Thousands of baby pelicans grunt and hiss at their parents in tightly packed nests on Gaillard Island, a feathered paradise situated off the coast of Alabama.
The 1,300-acre, man-made island is hosting more than 50,000 birds this summer as nesting pairs gather to raise babies. That number would be considered high in any year, but it's a particularly surprising sight a year after oil from the BP spill fouled surrounding waters.
The Deepwater Horizon rig explosion spewed more than 168 million gallons of oil into the Gulf of Mexico over three months, the largest spill in U.S. history. But so far, there is no evidence of deformities or ill health among the young on Gaillard Island.
Scientists speculate that the baby boom probably results from an abundance of fish left undisturbed in waterways where the federal government banned commercial and recreational fishing last summer, providing a feast for shore birds.
In a speech this spring, the executive director of the nearby Dauphin Island Sea Lab said the fish populations in that part of the Gulf were larger than he had ever seen.
The population of the pelicans, terns, laughing gulls, egrets, ibis and little blue and tricolored herons nesting on Gaillard Island is determined by the food supply, said Roger Clay, a wildlife biologist with the Alabama Division of Wildlife and Freshwater Fisheries.
"If something was wrong with the food, the first place it would show is with the birds," said Clay, also known as the "the pelican guy."
That fact was painfully true in the 1960s and 1970s when the agricultural chemical DDT caused birds to produce deformed eggs. Many species, including the brown pelican, teetered on the brink of extinction.
A fondness for pelican feathers in women's hats in the 1900s resulted in over-hunting and decimated populations. The four nesting pelicans on Gaillard Island in 1983 were the first sightings of the birds in years in Alabama.
The number of pelican pairs has grown since then to an average of 4,000, but this year looks to be nearly 5,000, Clay said.
"The pelican has made a terrific comeback," said Celeste Hinds, field trip coordinator for the Mobile Bay Audubon Society, which monitors the bird population.
"So far, we have seen very little impact from the oil spill, and we are pleased that it has not affected the nesting habits of the brown pelican," Hinds said.
Clay said nearly every shore bird commonly found in Alabama nests on the island, which was created with dirt from a dredged shipping canal. Far enough from land to prevent predators such as feral cats and raccoons from reaching shore, the island provides protected habitat for ground nesters.
People are not allowed either, but many boats circle the two-mile island for some of summer's best bird-watching.
Each nesting pair typically raises two youngsters, even in a three-egg pelican nest. The first two baby birds to break the shell generally out-compete the last arrival.
Pelican parents do little to protect their young, but the babies hiss, scream and aim their beaks at the eyes of intruders. Nests sit close to each other as a defensive measure.
The royal terns prefer 12 inches of space between nests and raise two young per nest. About 3,000 pairs inhabit the island, along with approximately 1,000 more pairs of Caspian, sandwich, gull-billed and common terns.
Bursting with birds, the island is hosting its maximum number of pairs. Clay began his weekly visits to the nests three years after the island was formed in 1983. He said the population peaked in 1992, with some years, such as this one, booming with babies.
"One year does not make a trend, so I hate to jump to any conclusions, but I am taking this as a positive sign," he said.
(Editing by Colleen Jenkins and Ellen Wulfhorst)