The massive die-off of seabirds has made its way to Alaska's Lake Iliamna, North America's eighth-largest lake. Thousands of common murres were found dead at the southwest lake, leaving experts puzzled as to what caused the event.

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

Piatt said that although murres occasionally land in fresh water, to have such a large amount of them do so is unprecedented.

"You figure it's a misguided individual," he said. "To have 6,000, 8,000 birds in the lake is pretty mind-blowing, really. I've never heard of any such a thing anywhere in the world."

The strange occurrence began in March 2015, when dead common murres began to make their way onto Alaska beaches, all of them showing signs of starvation. Following the storms in late December, 8,000 were found at the Prince William Sound community of Whittier, and with the recent findings the total death count has hit 36,000.

Despite these high numbers, not all of these birds wash ashore and few beaches have been surveyed due to Alaska's large coastline, meaning there could be many more deaths that have gone unnoticed.

Randy Alvarez, a commercial fisherman and member of the Lake and Peninsula borough assembly, believes that the birds likely made their way to Alaska after being unable to find food in the Pacific. With Iliamna's population of salmon smolt, they probably found a new source of food.

Alvarez said that typically, he and his friends catch smelt, a small silvery fish, in standard winters, but that this year has been bad for them as well.

"This was the worst anybody had ever seen it for smelt," he said, suggesting that it could stem from the third straight year of higher temperatures in the North Pacific and expressing worries that salmon might have a rough time as well. "I think something is not right."

Federal agencies are currently working together to determine the exact cause of the murre deaths and are examining numerous possibilities including starvation, weather, parasites and disease.

Wildlife biologist Sarah Schoen is one of the experts examining the common murre corpses and said that one had an empty stomach as well as emaciated pectoral muscles, which allow it to fly.

"As the bird starves, the body eats the muscle for energy," she said. "The muscle becomes more and more concave."

Despite signs pointing to starvation so far, there are numerous other factors that likely played into the deaths of the birds, and further research will need to be conducted to uncover them.

"This is the thing about this die-off," Piatt said. "We don't even know what we don't know."