Maine birds are in trouble as species dwindle across North America

Maine’s location and diverse wildlife habitat have long made the state a hospitable home for hundreds of different bird species. But as climate change alters habitats, some birds aren’t being found here anymore — and experts say that humans need to help change that.

There are 233 distinct birds breeding in the state, according to the Maine Breeding Bird Atlas, a five-year project completed last year by the Maine Department of Inland Fisheries and Wildlife. Among them are 33 newly confirmed species that have arrived since the first atlas was conducted in 1978-1983.

Despite that, some Maine bird species are in rapid decline. Last month, the wildlife department added five birds to the list of endangered or threatened species in the state, bringing the total number to 48 species of concern. The list includes five kinds of sparrows, five types of swallows and five varieties of warblers, among others.

Of particular concern in Maine is the saltmarsh sparrow, which was added this year to the state’s list of endangered birds. Four others — the bank swallow, Bicknell’s thrush, blackpoll warbler and cliff swallow — are newly listed as threatened species.

The five species were the first additions to those lists since 2015.

“We hate to see a bird get listed, put on the endangered species list, but at least that will get more attention, hopefully receive more funding, that more needs to be done,” said Doug Hitchcox, a naturalist at Maine Audubon and the outreach coordinator for the Maine Breeding Bird Atlas.

Maine’s changes follow a national trend identified in an eye-opening 2019 study of North American birds published in the journal Science that found that in the previous 50 years, North America had lost nearly 30 percent of all bird species. The Cornell-led study found that 90 percent of the 3 billion birds lost in a 50-year span belonged to only 12 families, including sparrows, warblers, finches and swallows.

Ken Rosenberg, a senior scientist at the Cornell Lab of Ornithology and American Bird Conservancy and the lead author of the study, said a key factor is how humans alter natural ecosystems.

Habitat eradication or disturbance and effects of climate change are determining what birds eat, where they live and breed, and whether they will survive challenges, both natural and manmade, experts said.

Gov. Janet Mills last month signed into law a bill requiring the wildlife department to review listed species and others under consideration every four years and report back to the Legislature’s Committee on Inland Fisheries and Wildlife. Before that there was no prescribed time frame for conducting reviews.

The saltmarsh sparrow is among the Maine birds whose plight is well understood. Their particular coastal habitat — salt-hay marshes — is already limited in size, but the threat of rising ocean levels caused by climate change threatens to shrink it. There are only 15 salt-hay marshes, all of which are located in the southern part of the state, said Danielle D’Auria, the wildlife department’s waterbird specialist and acting bird group leader.

“They’re very vulnerable to the extreme high tides that end up flooding their nests,” she said of saltmarsh sparrows. “As the sea level rises, that’s more extreme.”

The state has worked to identify ways to restore or improve those marshes, but the extensive residential development that already surrounds them means they cannot expand naturally and will likely disappear from Maine.

“[Saltwater sparrows] have been given a lot of attention recently, because they’re actually slated to go extinct in the next 50 years,” D’Auria said.

Hitchcox said some birds are disappearing faster than others, particularly what he called an alarming trend with flight birds that eat insects.

“They’re dependent on insects that are not quite at the bottom of the food chain, and if their populations are tanking, that’s a major indicator of the health of our ecosystem,” Hitchcox said.

In that group are the threatened bank swallow and cliff swallow, along with the endangered saltmarsh sparrow.

D’Auria said bank swallows have declined 99 percent overall, 10.9 percent per year in Maine, in the last half-century.

“That is a crash. They have just vanished suddenly over a very short period of time,” said Bob Duchesne of Old Town, an Outdoors contributor for the Bangor Daily News who is a longtime birder, guide and conservationist.

Saltmarsh sparrows have experienced a 10.6 percent annual drop in Maine since study began in 1998, while cliff swallow populations shrunk 6.9 percent per year from 1966-2019.

Duchesne, who formerly took bird seekers to view bank swallows at a spot behind the Medway post office, isn’t sure there are any still living there.

Some of the bird population changes have happened without explanation. For instance, cliff swallows and bank swallows have experienced a 99 percent decline since the 1960s, but there is no clear understanding of what has happened, D’Auria said.

Likewise, birds such as bobolinks and meadowlarks, once plentiful, are few and far between. Duchesne believes the fields where those birds nest are now being mowed earlier in the year.

“They don’t have successful nesting if they’re mowed over,” he said. “And we’re seeing a lot of that, so the grassland birds have crashed as well.”

Duchesne’s observations in the field are confirmed by trends being established by scientific study.

D’Auria said the conversion of traditional farmland to overgrowth, housing development and other uses such as solar farms have shrunk available habitat for many birds.

Another coastal bird being watched closely is the iconic Atlantic puffin, which is not in trouble yet, but at risk because of the rapid warming Gulf of Maine and corresponding changes in fish populations.

“Many millions of tourism dollars come into the state from people who want to see puffins,” Hitchcox said. “Maine’s the only state that has Atlantic puffins nesting, so that’s a big draw.”

Some of the same environmental factors hurting Maine bird populations also likely are responsible for the arrival of new birds. Warming temperatures, from the Arctic all the way to South America, are altering how far birds migrate and where they spend their summers and winters.

“With a lot of our birds we’re seeing this northward range expansion as a result of climate change,” Hitchcox said.

Migrating birds also are dealing with changes happening in their wintering areas, while migration alone subjects them to threats from window strikes, power lines, vehicle strikes and, the top bird killer, outdoor cats.

“Cats are the biggest problem,” Hitchcox said. “Cats are not a natural part of the landscape.”

But the news for Maine birds isn’t all grim.

Waterfowl are faring well, along with wading birds such as great egrets and sandhill cranes, ospreys, peregrine falcons and raptors such as the cooper’s hawk.

Corvids, such as crows, ravens and blue jays, also are on the rise. The merlin, a raptor, also has pushed east and is now more common in Maine. Red-bellied woodpeckers, rare in the state as recently as the 1980s, are breeding in southern Maine.

Bird experts remain hopeful that education, habitat management and conservation efforts can help some species rebound under the right circumstances.

That’s what happened with the bald eagle, which was nearly wiped out in the 1960s and 1970s because of pesticides like DDT. It was added to the species protected by the Endangered Species Act in the 1970s, building on a framework designed to protect it. The species rebounded from the brink of extinction. In 2007, bald eagles were removed from the list of endangered or threatened species.

Waterfowl, which rebounded in part through better management practices and conservation efforts, also are a success story.

“Once we figured out how to manage the various uses there — having hunting seasons with bag limits and that huge piece of the land conservation, which is largely from duck hunters having to buy duck stamps — now the population of ducks and geese, all the waterfowl, are increasing,” Hitchcox said.

Birds in Maine face continued changes as they attempt to nest, breed and survive. Scientists hope that through continued study, including projects like the Maine Breeding Bird Atlas, they can better identify the factors affecting the decline of birds and find ways to make sure some of them don’t disappear for good.