When a heat dome enveloped the Pacific Northwest in 2021, baby hawks, unable to fly, threw themselves out of their nests, attempting to reach the cooler forest floor. Millions of shellfish dried up and died. And conservationists had to scoop up endangered young salmon out of rivers and into indoor tanks to keep them cool.
Maine hasn't faced a heat dome on that scale. But given the changing climate, Maine CDC Environmental Epidemiologist Rebecca Lincoln is worried it's only a matter of time.
"This absolutely could happen here. It is Portland, Maine, and Portland, Oregon. The climates are really similar. The populations are really similar. The sort of mix of urban and rural is similar," she says.
As human-caused climate change warms the planet, summers are getting hotter. The number of days over 90 degrees is expected to at least double across parts of Maine by 2050.
During a heatwave, Mainers can head to the beach, the movies, a cooling center or turn on the AC if they have it. But Maine's wildlife don't have that option. On days where the mercury is high and the heat index is even higher, birds, fish and mammals can be at risk.
Extreme heat exacerbates the issues wildlife are already facing: drought, habitat loss and the spread of disease. Development prevents animals from being able to flee to cooler areas. Others are likely to take new risks by venturing places they normally wouldn’t, in search of shade or water — this is often why animals, from turtles to moose, are found crossing roads in summertime.
At the Center for Wildlife in York, Executive Director Kristen Lamb checks on a painted turtle in recovery after being run over by an SUV.
"So, we do aluminum tape across the fracture," she says.
Turtles don't usually move locations in summertime — they're supposed to pick a spot a stay put.
"They go up Maine, they go up to camp," says Lamb, laughing.
That this guy was on the move likely means it was searching out a colder body of water, Lamb says.
The team rescues about 2,500 animals each year, and field roughly 15,000 calls on their animal rescue hotline. In the summer, the hotline can field 50 calls per day, and they admit 30 animals per day on average.
Lamb opens the door to a cubby containing a group of baby birds. She says the Center admitted these 17 young in the week after a heatwave.
She starts dolling out tiny mealworms into their open, gaping mouths.
"So when we open the door, it's almost like mom returning back to the nest, that sound of her wings flapping back, landing back, they would start that frenzy. The same happens here when it's feeding time and when we open the door," Lamb says.
Chimney swifts use their own spit as glue to attach their nests to hard surfaces.
"They have special glands that makes their saliva like a cement," said Lamb.
But extreme heat can cause their nests to come unglued and fall down. Lamb says people were finding nests full of baby birds in their fireplaces during the heatwaves this summer.
Lamb says, in general, most animals are trying to expend as few calories as possible during extreme heat.
"Gulls that are on the hot beach, you can see them start to open-mouth breathe. North American porcupines seek a cool patch of the earth and literally spread their entire bodies out. We call it a sploot," she says. “They are basically trying to not move during those hot days.”
But not moving means not feeding themselves or their young.
“It’s basically like a loss of work day," she says.
If there are too many hot days in a row, it can start to impact reproduction, the ability to fight off illness, and other critical functions. And it's not just birds, mammals and reptiles.
Heat poses a significant threat to Maine's shellfish, says Ari Leach, a nearshore resource scientist with the Department for Marine Resources, because the intertidal zone is already a high stress environment.
"Some clam species will experience mass mortality during heat waves, particularly the soft-shell clams are impacted negatively when it comes to spawning," she says.
DMR's nearshore program has recently started a long-term climate study of 12 different clam flats up and down the coast. Leach says, over time, they'll monitor temperatures at the sites. But she says she's already noticed shellfish in distress this summer.
"For example, I saw a couple of soft-shell clams that were just laying on top of the mud with their siphons extended," she says.
Not normal behavior she says. And during heat waves, harvesters are reporting die-offs of soft-shell clams, too — they think it could be the high salinity of the ever-shrinking pools of standing water.
"When we see these periods of extreme temperatures, especially, you know, consecutive days in a row. It just makes the shellfish that more susceptible to becoming contaminated," she says.
Leach says they hope to run the shellfish study for the foreseeable future. But even with the right data, there's not much they can do to save distressed shellfish during heatwaves.
Back at the Center for Wildlife, we say goodnight to the baby birds. Lamb tells me she doesn't think people always realize how closely connected humans and animals are. Take the chimney swift.
"Parents and a nest of young can consume 12,000 insects in a day when they're growing. So if we think about that connection to human health, agriculture, forestry, even our favorite, you know, flower gardens and veggie gardens, if we took out one family of chimney swifts, that's like 100,000 insects more within a week," she says.
At the federal level, the Trump administration has proposed changes to the Endangered Species Act that wildlife advocates say would significantly weaken protections and threaten progress made towards species recovery.
Several executive orders have instructed officials to change the act to make it more "business-friendly," which could mean skipping environmental reviews typically done before greenlighting new energy projects. Final changes have not yet been made.
The state Department of Inland Fisheries and Wildlife is currently drafting its once-a-decade wildlife action plan. While it does take climate change into account, it doesn't specifically plan for extreme heat.
This story was reported as part of a collaboration between the Portland Press Herald and Maine Public.