Hounded by hunters and fishermen, driven to near-extinction by chemical pollution, the brown pelican has survived a century of human abuse — only to face another challenge from the giant oil spill threatening to devastate the Gulf of Mexico marine environment.

 

The odd-looking seabird with a distinctive pouch beneath its foot-long bill was removed from the federal endangered species list only last November. Now its recovery could be undermined by millions of gallons of oil polluting the Gulf since an April 20 rig explosion.

 

So far, no brown pelicans are known to have died from causes related to the spill. That's likely to change if the oil fouls their nesting and feeding grounds along coastal and barrier islands, officials with the U.S. Fish and Wildlife Service say.

 

The plight of Louisiana's state bird is emblematic of dangers the disaster poses for the region's wildlife.

 

"I would not say there's going to be any species wiped out because of it, but it's a very serious situation," said Bob Love, coastal resources administrator for the Louisiana Department of Wildlife and Fisheries.

 

The brown pelican is particularly at risk because it dives beneath the water's surface to forage. Not only could pelicans eat tainted fish and feed it to their young, but their feathers could become oil-soaked, causing hypothermia or drowning.

 

Also in harm's way are at least 12 Gulf species listed by the federal government as endangered or threatened, including birds, sea turtles and the sperm whale.

 

Officials say they don't know the death toll from the spill, although state wildlife veterinarian James LaCour said 10 oil-soaked bird carcasses have been found in Louisiana. A total of 154 sea turtles, most identified as the endangered Kemp's ridley variety, and 12 dolphins have washed ashore in recent weeks, but it's unknown whether oil killed them.

 

Three oily brown pelicans have been found alive. Two other pelicans have turned up dead, but the cause is uncertain.

 

Another danger: The oil could kill vegetation that anchors the marshy islands where many pelicans nest, hastening erosion that has already rendered some of their former habitat unsuitable.

 

Biologists say it will take months or years to assess the damage to wildlife, and caution against underestimating it because no massive die-offs have taken place. Many fish and birds may be avoiding the oil slick, but that will become harder if it reaches coastal marshlands where a multitude of creatures spawn, nest and feed.

 

Federal scientists are watching vulnerable species for signs of distress. Of particular interest is the brown pelican, thousands of which were slaughtered a century ago by hunters who coveted its plumage and commercial fishermen who believed pelicans were gobbling too many fish.

 

They nearly went extinct in the 1960s. Eating fish contaminated with the pesticide DDT caused them to lay eggs with thin shells that broke under mother birds' weight during incubation. After the chemical was banned in 1972, they bounced back and now total about 650,000 worldwide, including 400,000 in Peru.

 

The estimated population in the northern Gulf region is about 40,000.

 

"They're still just clinging to existence," said David Ringer, a National Audubon Society spokesman as he watched crews lay protective boom around small islands in the path of the oil slick.

 

Pelican Island, so named because so many of them once nested there, was awash in birds — royal terns, black skimmers, laughing gulls and many more. But only a couple of brown pelicans could be seen, gliding just above the water's surface in their constant hunt for fish.

 

The roughly 10-acre islet has shrunk by about 50 percent over the past decade. Like other coastal wetlands, it is eroding from storms and rising sea levels, while levees prevent the Mississippi River from depositing fresh sediment.

 

Brown pelicans seek elevated spots with short grasses for nesting. When they washed away, the birds abandoned Pelican Island for other places — some of which are eroding as well, and the pace may quicken if oil kills vegetation holding sediment in place.

 

"It could be the strikeout punch," said Gregory Butcher, bird conservation director for the Audubon Society.

 

Despite their gangly appearance — their long necks, stubby legs and wingspans that often exceed 7 feet prompted Butcher to jokingly liken them to to B-52s — they are nature's perfect anglers, winging above the sea with keen eyes seeking schools of menhaden or minnows. They suddenly plunge and emerge with huge mouthfuls, straining out water through the pouches beneath their bills.

 

The pelicans might ingest enough oil to sicken or kill them, depending on the amount, said Wes Tunnell, coastal ecology and oil spill expert at Texas A&M University-Corpus Christi. Oil also causes matted plumage, making it harder to stay afloat when they rest on the water's surface and boosting the risk of hypothermia.

 

If oil coats the waters around islands and marshes, it could cause prey fish numbers to plummet, said Aaron Pierce, a shore bird specialist at Nicholls State University in Thibodaux, La.

 

"Even if the pelicans can avoid the sheen, they must be able to forage within a reasonable distance to keep their chicks alive," said biologist Paul Leberg of the University of Louisiana at Lafayette. "We've been very lucky the oil has stayed so far offshore."

 

Some advocates want the government to return the pelicans to the endangered species list. But scientists generally say it's too early to decide, and Philip Kloer, a spokesman for the U.S. Fish and Wildlife Service, said re-listing is not being considered for now.

 

Scott Walter, a Louisiana-Lafayette wildlife biologist studying brown pelicans on Gulf barrier islands, said he will try to determine how the oil spill affects their reproduction.

 

Restoring their endangered status, Walter said, might become necessary if food contamination and habitat loss cause a population crash.

 

"They're in a very precarious position," he said.

 

Copyright 2010  AP News