Newswise — North America has lost an estimated 3 billion birds since 1970—a nearly 30% drop across species—mostly due to habitat loss and degradation. So when a team of researchers repeated a bird population study they did 30 years earlier in a very large commercial forest landscape in Maine, they were stunned to find more birds than before.

“When we started this project, we expected to add to the pile of bad news,” says Michael Reed, a professor of biology in the School of Arts and Sciences at Tufts University and co-author of the study. “So we were very pleasantly surprised to find that, for most of the bird species in our study, things were actually looking up.”

The research team wanted to see if bird populations and habitat use had changed over the decades, particularly given a shifting forest landscape. “Forest management practices in Maine have changed significantly since the early 1990s,” says Reed. Due to social pressure, clearcutting has become much less common in Maine. Today, most logging operations remove fewer trees per acre—returning to spots every decade or so—and spread their activity across a broader area

The study, published in Biological Conservation, found that 26—or more than half—of 47 species counted by the researchers had significantly increased in numbers since the early 1990s, while populations for 13 species (or 28%) had remained stable. That’s contrary to what happened across much of the continent, with the North American Breeding Bird Survey showing that 35—or 75%—of the same species analyzed had seen their numbers decline, both regionally and continentally, for the same timeframe.

But what makes the commercial forests of Maine so different from other forests in the northern Atlantic states and North America? And can we learn anything from them to bolster bird populations regionally and nationally?

“Numerous factors are likely behind the abundance of bird populations we see in northcentral Maine,” says Reed. “We can’t know what they all are, but we know at least one: It’s all forest up there.”

The original and current study took place in a 588,000-acre commercial forest nestled within 10 million acres of commercial, public, and protected forest landscape. Together, these woodlands create the largest contiguous tract of non-developed forest east of the Mississippi. The habitat is recognized worldwide as an Important Bird Area, an area officially recognized as critical for protecting bird species and biodiversity by a coalition of international bird conservation groups.

The remote forestland is also one of the darkest places left on the East Coast. “Most bird species migrate at night, orienting by the stars,” says John Hagan, the study’s senior author and the founder and president of Our Climate Common. “So it may be when birds flying at night get tired, they look down, spot a vast patch of darkness, and decide it’s a good place to land and raise young.”

Many of the bird species observed seemed more flexible in their habitat use than previously thought; the researchers have another paper on these findings in the works. This suggests that high-quality forest next to more average forest may still be appealing enough to attract and support more birds over time. Individual birds often return to breed where they were hatched, and many migratory species are drawn to areas where others of their kind are already present. As Reed puts it, this may mean that “the rich get richer” when it comes to birds in Maine’s commercial forests.

Much of the population growth came from more birds per acre, not more habitat. “You’d expect bird numbers to go up if there’s more habitat,” says Reed. “But we actually saw increased numbers for some species whose main habitat acreage stayed the same size or even decreased from the 1990s. For example, in places where we previously counted two ovenbirds singing before, we now counted four.”

Data from one species—the golden-crowned kinglet—suggests that how forests are managed may affect species’ ability to thrive. These tiny, round songbirds are declining sharply across much of North America, including in the commercial forests of New Brunswick, Canada. But just over the border in Maine, their numbers are rising.

In Canada, commercial forests are commonly replanted in neat plantation-style rows, creating simpler forests, with less understory and trees that are all the same age. In contrast, Maine’s commercial forests rely on natural regrowth, creating denser forests with a broader mix of tree species and ages. Reed and Hagan hypothesize this more natural approach may offer better shelter or support more of the insects that kinglets need to raise their young.

Despite the widespread increases, bird numbers for 14 species—about 30%—still declined in the study area. The researchers hope to more closely examine the pressures faced by these decreasing bird species, including species like the winter wren and the Canada warbler, to see if commercial forestry could do something differently to better support them. They are particularly worried about steep declines in mature trees—some more than 200 years old—and its impact on the bird populations. Hagan is now leading additional research to assess this conservation threat. The threat could be on their migration or overwintering grounds, in which case little can be done in Maine to improve their numbers.

Even though about two-thirds of U.S. forestland is available or used to produce industrial wood products, the research team believes theirs is the first bird survey to compare species population numbers in a commercial forest over a long period of time. And given the 521 million acres of commercial U.S. forestland, they hope it certainly will not be the last.

In the face of ongoing human habitat expansion and continental declines in bird populations, the team says it’s important to understand how all types of forest ownership may help create important sanctuaries for birds. “Birds also may be thriving in commercial forests in Michigan, Wisconsin, and Minnesota, which are managed similarly to those in Maine,” Hagan says. “Hopefully, someone will look to see.”

“Many people don’t expect places where you harvest wood to serve as valuable habitat because they are cutting trees down,” adds Reed. “But nobody thinks the goal of a farm is to cut down corn—it’s to grow it. And commercial forests grow trees.”

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How to Help the Birds at Home

You may not own an acre of land—never mind hundreds of acres—but you can still bring some qualities of Maine forestland to your own yard.

Plant a tree that is native to your area.Add native shrubs, which provide vital food and shelter for birds while offering multi-season visual appeal for you.“Leave the leaves” in the parts of your yard where you are creating understory. Nature abhors a leaf blower—and it means less yardwork and free mulch for you.Fight light pollution by reducing outdoor lighting to what’s truly necessary.Where safe to do so, leave dead trees standing. “Snags” provide valuable habitat for owls, woodpeckers, and cavity-nesting birds.Replace part of your lawn with native plants. Check out Douglas Tallamy’s book Nature’s Best Hope for ideas.