Small Seabirds Washing Up Dead on Northwest Beaches

Hundreds of a small, blue-footed seabird called the Cassin’s auklet have been washing up dead on Northwest beaches. So far, scientists don’t know exactly why.

Diane Bilderback is a volunteer with COASST, a University of Washington citizen science project. Until this fall, she had found very few Cassin’s auklets washed ashore.

“That’s when we started seeing not only dead birds come ashore, but a few living birds. They were washed ashore in some of the high storms, and then shortly later they would die,” she said.

Bilderback and her husband found 10 dead auklets during their November survey of their assigned one-mile of beach near Bandon on Oregon's south coast. They found about the same number again in December. On New Year’s Day, she counted six dead auklets on another section of beach near town.

A bit farther up the coast, near North Bend, Ken and Cathy Denton were seeing similar numbers of dead auklets.

“We’ve seen a lot of common murres, but those are common,” Ken Denton said. “This is the most we’ve seen of something else.”

Cassin’s Auklets are small black and white migratory birds, about six inches long. Most nest in colonies off British Columbia and then travel south to feed in the current off of California, Oregon and Washington.

All three states are seeing elevated numbers of dead birds. In 2014 COASST counts from Oregon and Washington put the number of dead auklets at more than 800 – the second-highest mortality of all the species recorded. That number is likely much higher since each stretch of beach is surveyed only once a month.

COASST participants in Oregon process Cassin's auklets on a
seabird survey in late December.
Credit: L. Doyle/C. Willoughby/COASST

Volunteer counts indicate Oregon's north coast has seen the highest number of Cassin’s auklets wash ashore. Tests by the National Wildlife Health Center show they were young and malnourished and likely died of starvation, not disease or exposure to a toxic substance.

But why now? And why this specific species of bird?

Scientists say the Cassin’s auklet population boomed this year. And it’s the birds that hatched this year that are ending up dead on West Coast beaches.

“New birds are just like any young wildlife, not as good as survival,” said Julia Parrish, COASST executive director.

Young birds are less capable of surviving the winter storms that pound the coast.

“So part of what we think we’re seeing is the aftermath of a really successful breeding year in British Columbia.”

But Parrish says that can’t explain the whole story. She speculates that something could have changed in their food source – for example, it could have come closer to shore.

In this scenario, the number of young birds dying could very well be proportional to previous years. But the carcasses would be more likely to wash ashore and be counted before being scavenged.

But this is a hypothesis – and one that’s not easily tested because of weather conditions offshore.

For now, Parrish calls the die-off of Cassin’s auklets unusual but not cause for panic.

“We don’t think right now it’s something that would seriously impact the population,” she said.

But usually, she says these single-species die-offs, or wrecks, don’t happen over such an extended period of time.

“This has been on and off for two and a half months, and that gives us pause,” Parrish said.

A sample of Cassin’s auklets that washed ashore in December is currently being tested by federal wildlife scientists.