The melody of birds at Acadia National Park is fading, and new research sheds light on why this is happening. Over the last fifty years, the park has grown quieter, partly because of climate change.
The sweet song of the Swainson’s thrush is becoming rarer, replaced by the harsher sounds of the red-breasted nuthatch. Some birds, like the bay-breasted warbler and the olive-sided flycatcher, have vanished. There’s a noticeable gap in the sounds of the forest.
Gillian Audier, a 26-year-old researcher, captured this changing landscape by recording the songs of birds last summer. “Visitors might not notice the decline, but it’s clear to those who remember what it used to be like,” she explained. The historical records show the woods used to be much louder.
Audier is affiliated with the Schoodic Institute, which collaborates with Acadia. Last summer, she retraced the footsteps of Ron Davis, who documented these forests back in 1959. Her findings revealed that 2025 will have fewer forest birds compared to Davis’s count. The most common bird, the black-throated green warbler, is now heard only a third as often.
“It’s still beautiful,” Audier said. “But it feels less alive.”
This decrease isn’t obvious to casual visitors. Many might think the forest is just as vibrant because they are unaware of its past. This “shifting baseline syndrome” means people accept a degraded environment as normal.
While climate change plays a big role, it’s not always apparent through direct bird loss. The Gulf of Maine, which affects Acadia’s weather, is warming nearly three times faster than the global average. As temperatures rise, the region’s unique cool-adapted trees, like the red spruce, are threatened.
By 2050, Acadia’s average temperature might increase by as much as 8 degrees Fahrenheit, according to a 2024 report from the National Park Service. This rising warmth doesn’t directly harm all birds, but it can disrupt food sources. For migratory birds, insects and plants might bloom or hatch too early, leaving them without enough to eat.
Audier spent months learning the sounds of 50 bird species. She rose before dawn to position herself at Davis’s historical recording sites. There, she quietly waited, logging various bird songs. Her meticulous work revealed that three of the top five birds recorded in the past were no longer common.
Audier’s observations coincide with a broader trend: A 2019 study by Cornell University found that North America has lost one in four adult birds since 1970. This decline isn’t unique to Acadia; similar issues are noted across other forests as well.
Although the forest may seem quiet, Audier still uncovered moments of beauty that remind us of its past. She discovered sea urchin shells on the forest floor and recorded the hum of lobster boats blending into the background of bird calls.
Her research is part of a larger narrative. In 2024, Camilla Seirup updated Davis’s tree inventory. Interestingly, Seirup found that the red spruce, once seen as vulnerable, is more resilient than expected in the face of climate change. However, Audier’s findings suggest that Acadia’s songbirds are much more susceptible.
In a poignant moment, Audier met the now-ninety-year-old Ron Davis. They shared stories about their love for Acadia and its unique forests. He expressed delight that new scientists, like Audier, are building on his work to assess climate change impacts.
Though her fellowship at the Schoodic Institute has ended, Audier continues to monitor shorebirds in Massachusetts but often reflects on her Acadia experience. A research paper detailing her findings is on the way, promising to contribute further to our understanding of these changing ecosystems.
For anyone interested in the ongoing relationship between climate and biodiversity, fascinating insights can be found in the full report by the Gulf of Maine Research Institute here.
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Acadia National Park,Climate Change
