Role reversal: Avian flu makes birds a menace to cats

A healthy cougar doesn’t drag its tail in the mud.

That’s why Mark Elbroch, a big cat expert with the nonprofit Panthera, was alarmed when a game warden called him to see a young male mountain lion, emaciated, on the Olympic Peninsula. It was December, and the big cat was in a cow pasture near Sequim.

“It was so weak it couldn't pick up its tail,” Elbroch said. “It was dragging through the mud and the water that was out in this field.”

Elbroch guessed the cat probably hadn't eaten in about a month. It was standing in the field in daylight – cougars are normally stealthy and seldom spotted.

Wildlife officials decided to put the cougar, a young male, out of its misery. Elbroch said that was the right decision: “A week later or so, we get the results, and it was avian flu.”

Soon after, another young cougar died.

“Lo and behold, it’s avian flu that killed him, too,” Elbroch said.

A week after that, 20 big cats, including five African servals, four bobcats, four cougars, and two lynxes died from avian flu at the Wild Felid Advocacy Center, a nonprofit sanctuary for displaced wild cats on Harstine Island in South Puget Sound.

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Researchers in the state are racing to learn more about the virus before the next outbreak hits. The U.S. Food and Drug Administration is investigating the Harstine Island outbreak. Possible infection sources include the cats’ food or bird droppings.

Captive cats in sanctuaries eat raw meat, mostly poultry and beef, but also rabbits, rodents, and other donated raw food, according to Washington State Veterinarian Amber Itle.

“Meat and food sources have been tested with all negative results,” Itle said in an email.

Heat kills avian flu, but raw food can transmit the disease.

Portland-based Northwest Naturals recalled its raw-turkey cat food in December after an indoor-only cat in the Portland area contracted avian flu and died.

“We found two dead cougars. There could be a lot more out there,” Washington Fish and Wildlife Commission member Melanie Rowland said of the secretive big cats.

There’s still a lot Elbroch and others don't know, including whether mammals can transfer the form of the virus now circulating on the Washington landscape to each other.

Here’s what we do know:

“It’s now in our wildlife populations. It’s not just being carried here. It plays out, then it disappears, and then it’s reinvigorated with the next migration of birds,” Elbroch said.

Scientists and volunteers with the Olympic Cougar Project said they have the opportunity now to study bird flu in wild animals – to hopefully prevent it from spreading to people.

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Bird flu has been around a long time, with the first U.S. outbreak hitting East Coast live-bird markets in 1924. It has become a devastating problem for America’s industrial-scale chicken farms in just the past few years.

Scientists think it had not taken a major toll on American wildlife until recently.

But on those big chicken farms, the virus mutated and evolved into something much deadlier for poultry and wildlife alike.

“The risk to wildlife has dramatically increased,” said Katie Haman, a veterinarian with the Washington Department of Fish and Wildlife.

A falcon in Whatcom County became the United States’ first confirmed wild bird to succumb to the highly pathogenic avian influenza in 2012, and major outbreaks hit the state’s wild birds in 2022.

In the summer of 2023, Haman walked down a rocky beach on Rat Island, a half-mile-long wisp of sand and shrubs near Port Townsend and the northeast tip of the Olympic Peninsula. It was teeming with birds.

She was seeing if the major colony of Caspian terns there was infected with avian influenza.

Caspian terns are the world’s biggest tern, easy to spot from a distance by their black caps and almost comically large red bills. They aggressively defend their breeding colonies, like the one on Rat Island, sometimes attacking people who wander too close.

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Rat Island is closed to the public during breeding season to prevent such hostile encounters.

But these feisty feathered friends had no defense against a recent invader. The highly pathogenic H5N1 strain of bird flu tore through the colony.

“What we found was a tremendous number of dead birds and sick birds,” Haman said. “It was devastating, to be honest.”

To study the massive outbreak, and protect the health of visitors to adjacent Fort Flagler State Park, she and her team collected carcasses.

“We were bagging them up in industrial-size waste bags and carrying them off the island by Zodiac,” Haman said. “It was many, many trips back and forth with the Zodiac piled full of garbage bags of carcasses.”

They tallied 1,101 dead Caspian tern adults and 520 dead chicks.

In a study published in December, the researchers reported that avian flu had killed more than half the colony’s terns – or one-eighth of all Caspian terns on the West Coast – in a matter of weeks.

This flu had mutated enough to cause a major outbreak where it hadn’t before.

The scientists believe terns arriving from a colony near the mouth of the Columbia River – where workers have been protecting threatened salmon by making the fish-eating terns nest elsewhere – brought the deadly virus with them.

The researchers also found 16 dead harbor seals on Rat Island, in the first detection of the highly pathogenic flu in seals on the West Coast of North America.

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That raised concerns for other mammals, including the region’s endangered orcas.

“These terns that were resting in places where the seals were resting, they gave the seals the virus,” said Joe Gaydos, a wildlife veterinarian with the nonprofit SeaDoc Society on San Juan Island.

Gaydos said the virus did not spread from mammal to mammal.

“Now, in other places, Peru, it got into sea lions, and it went from one sea lion to the next to the next, and it just killed thousands of them,” Gaydos said.

For now, scientists say the risk to orcas appears very low, since, unlike seals, they don’t come ashore, where bird poop accumulates.

“So long as there's no really large active outbreak in the Salish Sea, the [orcas’] risk of exposure is really minimal,” Haman said.

The H5N1 flu has killed thousands of wild geese and ducks in Washington, as well as smaller numbers of eagles, hawks, falcons, owls, ducks, geese, swans, crows, ravens, sparrows, gulls, pelicans, cranes, and shorebirds, according to the U.S. Department of Agriculture.

Mammals that have fallen to the avian flu in the Northwest include raccoons, bobcats, coyotes, mice, skunks, and foxes.

Wildlife diseases are hard to fight directly. Though an avian flu vaccine exists and has been used on extremely rare California condors, there’s no feasible way to vaccinate or treat large numbers of wild animals.

Helping wildlife against other threats they face, like habitat loss, pollution, and predation by introduced species, can boost their odds of survival when disease strikes.

“There are other things that we can do to make species more resilient, right? We can increase their habitat quality,” Haman said.

Cougar populations in Washington are generally stable, though the estimated 200 isolated cougars of the Olympic Peninsula face risks from their lack of genetic diversity.

Gaydos said one of the best actions to help wildlife is to keep domestic cats indoors.

“Your cats are always better off to be inside, right? Cats kill a lot of birds. They could definitely get the virus as well.”

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To further help cats avoid the deadly flu, experts also recommend avoiding giving them raw food, just as they recommend that people not drink raw milk.

Gaydos said drawing attention to bird flu, as he and other experts do, is hard.

“I think a lot of people don't want to hear about it, unfortunately,” he said. “We are completely pandemicked out. But I think it still behooves us to pay attention to what's going on.”