The petition was submitted to the U.S. Fish and Wildlife Service.

The main U.S. breeding site for the yellow-billed loon is the National Petroleum Reserve-Alaska on the western North Slope of Alaska, the environmental groups said.

The Bush administration and the state of Alaska have high ambitions for future oil production from the 23 million-acre reserve.

Exploration is already underway in the reserve's 4-million-acre northeast section, and in January the Bush administration opened 8.8-million additional acres in the reserve's northwest corner to oil and gas leasing.

"This is not some strategic move on our part to try to hinder oil and gas development," said Mike Frank of petitioner Anchorage-based Trustees for Alaska. "There is a genuine concern that this species is seriously threatened, and that's why the petition was filed."

The yellow-billed loon also breeds in neighboring parts of Russia and Canada.

In Russia, there are threats to the species from commercial fisheries, which accidentally snare and kill the birds. Other threats come from general human disturbance, increased predation, marine pollution and the species' overall low population and low reproduction rate, the environmental petitioners said.

Seven of the petitioners are Russian organizations, and the environmental petitioners said they hoped for an international agreement to protect the bird in its entire range.

The species has already been granted special protections in Russia.

The yellow-billed loon is distinct from more common loons, and not just for its coloring, Frank said. "Experts say it appears to be much, much more sensitive to disturbance," he said. There are also gaps in information about the yellow-billed loons' migratory patterns, he said.

Karen Boylan, a spokeswoman for the Fish and Wildlife Service's Alaska office, said agency officials had not yet studied the petition and could not comment on it.

And the Bureau of Land Management, the federal agency that is overseeing oil and gas leasing in the petroleum reserve, is also studying the issue, a spokeswoman said.

"Wildlife is certainly something that we look at," said Jody Weil, a spokeswoman for the BLM's Alaska office. The yellow-billed loon is already considered a "species of concern," even though it is not formally listed under the Endangered Species Act, Weil said.