Study: Amid declining bird populations, these Maine forests show encouraging signs

HALLOWELL, ME - A recently published multi-decade study (PDF) in northern Maine suggests that maintaining large blocks of intact forest habitat helps to boost the prospects of some birds, even as bird populations decline across the U.S. and around the globe. 

Since 1993, 55% of the bird species surveyed in the area showed population increases

“These findings affirm that intact, ecologically diverse landscapes that include forests of many ages are key to the survival of some bird species, especially as stressors like climate change and sprawling development put greater pressure on wildlife across the board,” said Peter McKinley, senior conservation biologist at The Wilderness Society, a co-author of the study. “The timber industry has a part to play in maintaining the extensive areas of natural landscape that are needed to head off extinctions in some species. Collaboration with conservation partners and state and federal agencies helps complete the picture by enabling the protection of more mature forests in the landscape mix. It’s an important lesson about how much we need cooperation to meet modern conservation challenges.” 

McKinley and other researchers looked at a vast stretch of Maine’s northern woods known as the Wabanaki-Acadian ecoregion, the largest undeveloped forest tract east of the Mississippi River and an internationally known hotspot for birds. Surprisingly, and contrary to national bird population trends, just over half of the species they surveyed showed increased abundance compared to 30 years ago.  

The study contrasts northern Maine’s patchwork of primarily commercial forest interspersed with ecological reserves, which includes Katahdin Woods and Waters National Monument, to nearby areas in Eastern Canada that have a less varied forest makeup. The study concludes the former may provide higher habitat quality for many birds. 

In all, 55% of the 47 bird species surveyed showed increased abundance in the landscape since 1993—ranging from black-throated green warblers to hairy woodpeckers to ruby throated hummingbirds.  In contrast, 17% of species declined while 28% remained the same.  

Meanwhile, the authors noted, North American breeding bird populations have declined by about 30% since 1970—some 3 billion birds lost, with much of that decrease likely driven by habitat loss. Another study of U.S. bird populations, published in March 2025, identified dozens of species that are trending sharply downward, with habitat loss once again a major culprit.  

The study serves as a piece of much needed good news at a time of serious threats to biodiversity. It also backs up the need to conserve even more mature and old-growth forests, a habitat type that is associated with some of the species that declined. 

The new findings are another indication of the importance of conserving large intact and interconnected landscapes (including mature and old-growth forests). As climate change worsens, this is a key piece of the puzzle to ensure the adaptation and survival of species, ecosystems and the human communities that rely on them. 

Contact: max_greenberg@tws.org | newsmedia@tws.org