Anyone who has walked Homer’s beaches the past few weeks has seen a horrid event. Every few yards along the tidal wrack line, the white chests of dead birds stand out among kelp and driftwood. Some of the seabirds have been scavenged, a new food source that’s caused an influx of bald eagles not seen on the Homer Spit since the death in 2009 of Jean Keene, Homer’s Eagle Lady who used to feed eagles.

Something is killing Alaska’s common murres. In the summer of 2015, the murres also suffered a complete colony collapse and failed to breed.

Almost all the dead birds are murres, seabirds that in the summer swim in huge rafts near Gull Island or offshore. On a still summer evening, huge flocks can be seen flying just feet above the ocean surface. With big, duck-like feet, black backs and white breasts, they look like penguins. On land they’re helpless, but on sea they can swim and dive deep.

Bird experts advise beach walkers to leave carcasses alone.

Many of the murres appear emaciated and have starved to death, but scientists studying the die off don’t yet know what’s causing the murres to starve.

Not only are murres starving, they’re not breeding. Surveys of breeding colonies in Kachemak Bay and on the Barren Islands last summer showed no murres set up nests. Murres usually have a breeding success rate of 50 to 60 percent.

“We had complete reproductive failure, which is really rare for murres,” said Heather Renner, a bird biologist with the Alaska Maritime National Wildlife Refuge.

Hundreds and even thousands of murres have washed up dead on Alaska beaches in Kodiak, Homer, Anchor Point, Kenai and Whittier. In Seward, Anchorage, Palmer, Wasilla and Talkeetna, people also have been finding live, stranded birds in yards or on rivers and lakes — way outside the normal winter range for murres. By January, murres usually have migrated out to sea.

The Bird Treatment and Learning Center in Anchorage has taken in 220 murres since Jan. 1, said Katie Middlebrook, avian rehabilitation coordinator. At the Alaska SeaLife Center in Seward, 87 stranded murres have come in, said Laurie Morrow, education director and interim director of communications. Morrow said live murres have shown up as far inland as Mile 12 Seward Highway.

On New Year’s Day, a retired U.S. Fish and Wildlife Biologist counted 8,000 dead murres on a 1-mile stretch of beach in Whittier.

“That number is totally off the charts,” Renner said. “This whole region is having through-the-roof numbers in the last couple of days.”

Lani Raymond, a Homer birder who has volunteered with the Coastal Observation and Seabird Survey Training program since 2009, did her monthly COASST survey of a ¾-mile stretch of beach along Mud Bay heading east from the access road to the beach from the old airport parking lot. She counted 118 dead murres and also saw hundreds of dead sea stars.

“It’s really bad,” Raymond said. “It’s really depressing. The day we did the 118 murres and all those star fish, I was really upset.”

One day a month, COASST volunteers walk local stretches of beaches to look for dead birds. They count, tag and photograph dead birds and report information to the national COASST program in Seattle. Raymond said there have been so many dead birds they’ve been counting and photographing every 10 birds.

“Usually you go for a walk. You might find a bird, but often you don’t,” she said. “Right now it’s the pits, really the pits.”

Renner said local COASST volunteers have reported similar numbers as Raymond’s survey, with some sections having from 400 to 800 birds per kilometer. People have seen birds in woods above the high tide line, floating with debris in the Homer Harbor and even on the road.

COASST volunteers first noticed an increase in dead murres starting in July, when surveys showed about 2-3 dead birds per kilometer. Julia Parrish, a fisheries professor at the University of Washington, Seattle, and executive director of COASST, called that amount “elevated.” In an interview in July, she said a big die off would be like one seen at Kayak Island near Prince William Sound, with 1,000 dead birds per kilometer.

“That’s knee deep in birds,” she said then.

“You’re there,” she said in a phone interview on Tuesday.

Parrish said the recent numbers are 10 to 100 times the normal amounts. The average numbers for Alaska are 2-4 birds per kilometer — and continuing.

While scientists don’t know what’s causing the murres to starve, they do know this:

— A few birds of other species like auklets and guillemots have been found dead, but the vast majority are murres.

— There is no evidence of toxins in murre carcasses studied.

— None of the murres have avian influenza or cholera. If they did, other bird species also would be dying.

— For scavengers like eagles, crows and ravens, the murres appear safe to eat, and there have been no reports of scavengers getting sick.

— Murres also have been dying in above-average numbers in areas of the Washington and Oregon coast, but the rate of die off has dropped.

— The North Pacific from California to Alaska has seen an above-average warm ocean, an effect called “the Blob.”

— There also have been increases in harmful algal blooms, including in Kachemak Bay.

— The age of dead murres found varies, with 2- 3-year-old birds found as well as older murres. Murres can live up to 40 years.

Big storms could have contributed to the die off, stressing the already emaciated birds. Those storms also could have pushed the murres further north or could have tossed birds already dead out at sea up onto catcher beaches like at Mud Bay.

The big question in the murre die off is “Why are the birds starving?”

“It’s more a matter of ruling things out rather than having a best guess,” Renner said.

Parrish said she didn’t think it’s the harmful algal bloom that has been going on for 8 months.

“Is it the prey base, the krill, the forage fish, things like sand lance, the herring, that have rearranged themselves?” she asked. “Winter living as you know is tough in Alaska. These are scrappy birds. They’re used to it. Something else is going on.”

Normally after murres fledge in August or early September, the murres head out to sea, Renner said.

“Something’s going on. It’s causing a redistribution of murres,” she said.

The best guesses so far are that murre starvation is food source related and warm water related, Renner said.

“What the exact mechanism is, we’ll probably never know,” she said.

One theory is that warming ocean temperatures have caused prey fish to swim deeper, making it harder for murres to fish.

“That seems a bit of a stretch, because we know murres can dive pretty deep,” Renner said.

However, fishermen reported increased numbers of bait fish in Kachemak Bay, with fish so plentiful that it drew more humpback whales to the bay.

How the die off affects the total Alaska murre population also is unknown. Renner said murres number in the millions. Murres did breed in 2014, even though it also was a warm summer. Murres are indicators of environmental change, though.

“They’re telling us something is going on in the marine ecosystem,” she said. “The harder part is figuring out exactly what this means.”

For people walking the beaches and seeing so many dead birds, that can be troubling.

“Death is part of the ecosystem,” Parrish said.

For scavengers who rely on carcasses to get through the winter, that can be a good thing.

“It’s a very emotional things to be watching right now,” Morrow of the SeaLife Center said. “Science might be learning something, but we might not be able to mitigate it before it’s run its course.”

Michael Armstrong can be reached at michael.armstrong@homernews.com