A colorful, threatened sea duck whose numbers plummeted in Alaska may be reintroduced to the southwest corner of the state.

Federal wildlife officials are taking public testimony on possible environmental effects of a plan to move breeding pairs of Steller's eiders to the Yukon-Kuskokwim Delta, where the birds once thrived.

Only 11 nests have been found there in the past 18 years. The birds' declining numbers on the delta figured heavily in a 1997 federal decision to declare the species threatened.

The U.S. Fish and Wildlife Service proposal calls for the release of Steller's eiders raised in captivity at the Alaska SeaLife Center in Seward. The agency says it's unlikely a subpopulation of Steller's eiders will re-establish itself without the introduction of captive birds.

Wild Steller's eiders continue to breed on tundra near coastlines in Arctic Russia and on Alaska's North Slope near Barrow, the northernmost community in the United States. The Alaska population is the only one listed under the Endangered Species Act.

Scientists in 1997 could not identify why Steller's eiders declined. Predation of young by ravens, foxes or gulls, hunting, ingestion of spent lead shot and changes in the marine environment were considered. The decline remains poorly understood, according to the agency recovery plan.

Steller's eiders are the smallest of four eider species and average just 1.8 pounds.

Breeding plumage of the males makes them stand out. They have white heads with a green tuft and a small black eye patch. Both sexes have a blue wing patch outlined in white. In late summer and fall, according to the Fish and Wildlife Service, males molt and turn a mottled brown, making them look like females and juveniles.

In fall and winter, most of the Pacific population from both Russia and Alaska flies to U.S waters of the southern Bering Sea and the north Pacific around the Alaska Peninsula and the Aleutian Islands.

The deadline to submit comments is Nov. 16.

The agency by early winter expects to decide whether the reintroduction plan would have a significant environmental impact. If officials decide there is not, they will move forward with the next phase of reintroduction. That could include additional propagation of birds, assessment of habitats and the actual release of birds and eggs into the wild.

The agency said in its plan that reintroduction may affect communities on the Yukon-Kuskokwim Delta and near Izembek Lagoon, part of the Izembek National Wildlife Refuge. The closest community to that refuge is King Cove, which has unsuccessfully pushed for a road through the refuge so residents can have land access to emergency flights at a nearby all-weather airport in the community of Cold Bay.

Explore further Arctic ducks combine nutrients from wintering and breeding grounds to grow healthy eggs

© 2015 The Associated Press. All rights reserved.