Seattle is in smoke. What’s happening to the birds?

You haven’t been the only who’s wondered what happened to the birds. The wildfire smoke descended on this region, and just like that, for some of you, the birds you used to see in your backyard mostly disappeared.

That’s the report from some bird enthusiasts. Others haven’t noticed much change.

On the Facebook page for Western Washington Birders, which has more than 11,000 members, fans of the flying creatures on Sunday discussed what they saw happening.

Lorraine: “Living in Skagit right now, and always a plethora of birds/bird sounds. Deathly quiet … not one crow/eagle or anything since the smoke descended.”

Laurel: “The only birds I’ve seen since the smoke set in has been the family of crows that nest here in our yard (NE Seattle). And even they aren’t the normal level of raucous and active. Otherwise, it’s very still.”

In all kinds of ways, we live in ominous times.

And now the birds?

It’s true that this is the migratory season, and Joe Buchanan, a biologist with the Washington Department of Fish & Wildlife, says that songbirds such as warblers have begun their trek to northwestern Mexico and further south.

As for the year-round birds that he normally sees around his Olympia neighborhood, he says, “I haven’t noticed anything different. They’re still calling and singing.”

Still.

On Western Washington Birders, members have been posting photos of recent birds they’ve seen — goldfinches, California scrub jay, a pileated woodpecker.

But for other birders, things just don’t feel right as wildfire smoke envelops our area.

On Washington Tweeters, a site run by the American Birding Association, Scott Atkinson, of Lake Stevens, wrote about what he witnessed Monday at a 6- by 15-foot pond in his front yard.

“It has been a frequently-visited spot during the hotter months, as songbirds come to bathe and drink. Today, however, we had an unprecedented ‘mobbing’ of about 75 birds, mostly Pine Siskins, landing at the pond’s edges, and in the adjacent shrubs, in what appeared to be animated and stressed behavior,” he wrote.

In a phone interview, Atkinson says the wildfire smoke hanging over the area has lowered temperatures, so it wasn’t as if there was a heat wave.

The birds were flying around rapidly, trying to get to the pond, he said. “I had never seen anything like it.”

What happened with the birds that haven’t migrated? The answers are elusive, because, says Buchanan, with air pollution, “the magnitude and impact on bird populations are completely unknown.”

If you want better answers, they’re not there.

At the University of Washington, Olivia Sanderfoot has tried to find research papers on birds and, specifically, fire smoke pollution. She found only one, on the effects of the 2015 El Nino fires in Southeast Asia.

“I hope there are other papers, but I haven’t found them,” she says.

Sanderfoot is a fourth-year Ph.D. student at the University of Washington School of Environmental and Forest Science. Her dissertation is on birds and particle pollution, including fire smoke.

Her work has included putting together in a paper the various findings since 1950 on what air pollution of various sorts — from aerosols to heavy metals — does to birds.

It does plenty.

Respiratory distress and illness, with damage to lungs. Increased toxins in vital organs. Changes in behaviors such as homing. Laying fewer eggs.

She and colleagues have placed microphones and cameras in areas in Washington where there is a likelihood of wildfire smoke. They are measuring if there’s a decrease in bird sounds when it’s smoky.

Slowly, as they compile such numbers, a picture can be built of what’s going on.

But as for where the birds have gone in recent days, “My best guess is that birds are going to hang out more in interior spaces, reduce their activities and hunker down until it gets better, and it feels safe for them to forage,” she says.

On Wednesday, the National Weather Service posted that air quality across the region is expected to remain unhealthy to very unhealthy into Thursday. It said that region-wide smoke will continue through the rest of the week.

The plight of the birds in recent weeks is particularly ominous from New Mexico, and parts of Colorado, Texas and Arizona.

In a phone interview, “I’m guessing hundreds of thousands” of migratory birds, “if not higher,” died in recent weeks in those areas, says Martha Desmond, a professor at New Mexico State University’s Department of Fish, Wildlife and Conservation Ecology.

She talks about numerous dead birds getting picked up as road kill.

“We had people reporting the birds were lethargic and running around the ground, foraging for bugs,” says Desmond. Normally the birds would be getting insects in trees and shrubs.

“I had someone call and tell me they hit 10 birds while he was driving in the morning in northern New Mexico,” she says.

Desmond says autopsies will be done on the birds. “Maybe we can detect damage in their lungs or is there something else?” she says.

The researcher can only guess as to what caused the mass deaths.

Maybe the birds had inhaled smoke from the wildfires. Maybe the wildfires made them change the course of their migration and depleted all their fat resources. Maybe they then landed in parts of New Mexico that had been very dry, and there weren’t many insects for them to eat.

Sanderfoot, 27, says she enjoys going out to look for birds.

“It’s a peaceful activity that has brought me a lot of joy. Birds have given me so much renewed purpose in life,” she says.

And now they’re in trouble.

“It’s sad. It’s incredibly difficult for me,” she says.