ANCHORAGE, Alaska (AP) - Lake Iliamna in Alaska is North America’s eighth-largest lake, but nobody would mistake it for the Pacific Ocean. Not even a seabird.

So when thousands of common murres were found dead at the southwest Alaska lake - part of a massive die-off of a species whose preferred winter habitat is at sea - seabird experts were puzzled.

“We’ve talked about unprecedented things about this die off. That’s another one,” said John Piatt, research wildlife biologist for the U.S. Geological Survey.

Murres occasionally land in fresh water, Piatt said.

“You figure it’s a...