The cause behind unusual bird behavior on Alaska's coastline has scientists on high alert.

Beginning in May, wildlife officials began receiving reports of dead and dying seabirds from the northern Bering and southern Chukchi seas, including in the vicinity of the Western Arctic National Parklands. 

National Park Service investigators found 100 carcasses in a 4-kilometer stretch of beach in late June, most of which were murres along the coast of the Bering Land Bridge National Preserve. Although, investigators say other species were found there and in Cape Krusenstern National Monument. 

Scientists say the culprit is starvation-- but they don't know why. There has been no evidence of disease, and tests are pending to determine if birds were exposed to harmful algal toxins. 

A Facebook post from Alaska National Parks outlines the birds in question.

The post says Northern Fulmars are appearing unhealthy, and the Common Murres are going closer to shore than usual.

Off the coast of Katmai and Kenai Fjords National Parks, scientists are seeing the Fork-Tailed Storm Petrels unusually close to shore in large numbers.

A July 8 report shows large numbers of the Storm Petrels feeding in abnormally shallow water. Two days later, a report showed the number of birds in the area was much less, and instead, there were carcasses.

Scientists will continue to investigate, according to the post.

A report on the National Parks Service website shows this die-off is not the first in Alaska seas in recent years.

Wildlife authorities are asking the public to report observations of sick or dead birds to the U.S. Fish and Wildlife Service by calling 866-527-3358. Be sure to note the location, time and date observed; type and number or birds; photos of sick/dead birds; videos of any unusual behavior, such as drooping their head or wings. Citizens are reminded to wear gloves and keep carcasses frozen if you collect them. 

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