Lesser Goldfinches Expand North as Climate and Urbanization Open New Habitats.

Lesser Goldfinches, a small songbird once limited to the American Southwest, are extending their range northward through the Pacific Northwest at an exceptional pace, according to recent findings published in Ornithology. The study sheds light on how certain wildlife species are adapting to changes in climate and land use.

Researchers from Washington State University and the Cornell Lab of Ornithology analyzed data collected through citizen science initiatives—Project FeederWatch and eBird. These programs, powered by thousands of birdwatchers, enabled scientists to track bird movements across large geographic regions over time. Their analysis revealed a sharp increase in Lesser Goldfinch sightings between 2012 and 2022: populations grew by 110.5% in Washington, 66.3% in Idaho, and 16.9% in Oregon.

Mason Maron, lead author and a graduate of Washington State University, was initially surprised by the prevalence of the birds in eastern Washington. “I was seeing flocks of 30 or 40 at a time and assumed it was typical,” he recalled. “But local birders told me these birds weren’t here a decade ago. That’s when I started digging deeper.”

The expansion isn’t random, Maron explained. Instead, the birds appear to be following warmer river corridors and urban areas where food is plentiful and conditions are suitable. “They're adapting to landscapes shaped by human activity,” he said. “Both native and non-native plants in these areas are providing food, and warmer urban climates are helping them survive.”

The researchers identified several factors driving the birds’ movement: maximum annual temperature, annual precipitation, urban development, and proximity to major rivers. Interestingly, although Lesser Goldfinches frequently appear at backyard bird feeders, these did not play a major role in sustaining new populations.

“Feeders might help early arrivals, but they’re not enough to support a growing community,” Maron said.

Rivers, however, were identified as essential pathways for dispersal. “Rivers carry the seeds of weedy plants that goldfinches love, and people tend to settle along rivers, disturbing the soil in ways that benefit these plants—and by extension, the birds,” Maron added.

Once established, the birds tend to remain, forming stable or growing populations. “This isn’t just exploratory behavior,” said co-author Jordan Boersma from the Cornell Lab of Ornithology. “They’re moving in and staying.”

While their northward movement appears to be a response to environmental shifts, data from eBird’s Status and Trends project suggests Lesser Goldfinch populations are simultaneously declining in the southern parts of their original range.

Despite their success, the researchers warn against assuming all species will adapt similarly. “Some animals thrive under new conditions, but many are struggling,” Maron emphasized. “This study doesn’t suggest a trade-off. It just shows that adaptability varies widely.”

Understanding how birds like the Lesser Goldfinch respond to environmental pressures helps scientists forecast how other species might fare. “This kind of research informs conservation, city planning, and climate strategies,” Maron concluded.

The findings highlight the importance of long-term, community-driven data collection in understanding how wildlife navigates a changing world.

Source:https://phys.org/news/2025-04-lesser-goldfinches-north-climate-landscape.html

This is non-financial/medical advice and made using AI so could be wrong.