The Deepwater Horizon oil spill has many Great Lakes experts worrying about migratory birds making the trip home. But they say it’s too early to tell the fate of birds wintering in the Gulf.
Minnesota’s state bird — the common loon — and the endangered piping plover are among many Great Lakes species that ride out the winter months along the southern coast.
Although many have left for home already, some birds may still be in the region, where toxic oil is threatening habitats and food sources.
Experts aren’t sure what will happen to them.
“I think it’s the non-lethal effect of the spill that will be the most difficult for us to assess,” said Jack Dingledine, a piping plover recovery program coordinator with the United States Fish and Wildlife Service.
The oil spill’s immediate impacts are clear — hundreds of the agency’s members are rehabilitating birds coated in thick oil, Dingledine said. But it will take years of monitoring bird populations to understand the full impact of the spill.
Minnesota’s common loon population, the largest in the lower 48 states, winters along the southern coast from November until late April and early May, according to migration dates from a state bird group.
That’s around the same time when the Deepwater Horizon oilrig exploded and started leaking oil.
Baby loons stay in the Gulf until they’re old enough to make the flight, said Pam Perry, a nongame wildlife expert for the Minnesota Department of Natural Resources.
There are loons there now, and they may be affected by the spill, she said.
Once toxic oil coats birds’ feathers, they can’t swim or dive.
“They become hypothermic,” Perry said.
Oil can also contaminate the food chain. Birds that get sick from contaminated food aren’t able to migrate, Perry said.
“If they’re sick or contaminated, they aren’t coming back. They won’t be able to make the flight,” she said.
The American Bird Conservancy, a national non-profit organization, released a list of 10 sites most threatened by the oil spill, including wildlife refuges, parks and an Air Force base, along the coasts of Louisiana, Alabama, Mississippi and Florida.
Minnesota’s common loon is found in every location, according to the conservancy.
“We don’t know how it’s going to affect Minnesota loons. But we certainly are concerned; it’s our state bird,” Perry said. “This is really an important species for Minnesota.”
The department will continue to track the bird’s population through a state-monitoring program, she said.
Experts are also worried about the impact of the oil spill on the Great Lakes piping plover, a small, critically endangered shorebird that winters along the southern coast.
Last year, there were 71 breeding pairs in the population, Dingledine said.
The recovery program coordinator isn’t sure how the spill will affect bird numbers or migration. But its small population makes it a top concern, he said.
The agency has a bird-banding program that allows scientists around the country track the migration of the plover, which is known to winter in areas affected by the spill, Dingledine said.
Some birds stick to the coasts of Georgia and South Carolina.
“We’re still hopeful that those birds will not be affected,” he said.
The banding system will come in handy when the agency conducts studies on birds affected by the oil spill, Dingledine said.
In addition to extensive studies on how birds survive the spill, the agency will look at how food resources are contaminated and develop a protocol for testing levels of exposure in bird blood, he said.
Check out the American Bird Conservancy’s map of globally important bird areas and which ones are affected by the oil spill.