Less goldfinch climate and landscape modifications expand north as new habitat

A new study published in the Journal Ornithology shows that Lesser Goldfinches, a small songbird traditionally discovered in the southwest, expands northwards through the Pacific Northwest at an unprecedented rate, providing insight into how species adapt to environmental changes.

Washington State University researchers and Cornell Lab of Ornithology participated in two initiatives in the Cornell Lab (Project FeederWatch and Ebird) to analyze data from birdwatchers tracking species movements. This study found a dramatic increase in fewer Goldfinch populations in Washington (110.5%), Idaho (66.3%) and Oregon (16.9%) between 2012 and 2022.

“When I first arrived in eastern Washington, I was pretty new to bird watching and fewer goldfinches were new to me. I was looking at groups of 30 or 40 at a time, and I thought it was normal.

“What’s fascinating is how these birds adapt to human-modified landscapes,” Maron said. “They don’t just move north randomly, especially along the river, passing through urban areas where temperatures are warm and both native and non-native plants provide food.”

This study identified the maximum annual temperature, annual rainfall, urban development and proximity to major rivers as key factors associated with northward expansion. The authors pointed out that there are few goldfinches that frequently appear in bird feeders in the backyard, but when they saw how bird feeders affect facilities, bird feeders played a minimal role in establishing new populations.

“There was no significant connection to the bird feeder,” Maron said. The first individuals who arrive in the new area may go to the feeder as they have easy access to food, but Maron explained that “it will not be enough to maintain the entire population.”

The river emerged as an important corridor for expansion. “There are really a lot of weed plants and seeds in these rivers,” Maron said. “We, as people, like living along the river, so we disrupt the soil and it really creates this kind of chain of conditions that are perfect for them.”

Once established in new regions, Goldfinch populations remain stable. “Our results suggest that this species can colonize new environments fairly quickly,” says Jordan Boursma, co-author and research associate at Cornell Lab of Ornithology. “It’s not just that fewer Goldfinches are exploring these new realms… they’re moving, usually transforming into stable populations and even increasing their population.”

Less Goldfinch may be migrating north in response to the climate and habitat changes reported in this study, and in fact, Cornell Lab for ornithology eBird Status and Trend Projects shows that fewer Goldfinchs are decreasing in the southern parts of that range.

This expansion shows that some species can adapt to environmental changes, but Maron warns against a wide range of generalizations. “What we really show is that we know that many species are decreasing due to these changes.

“This species has proven to be significantly adaptable to changes in the environment,” Boersma said. “Understanding how birds respond to climate change and urbanization can help us predict how they will affect other species.”

“When we understand how wildlife responds to environmental changes, we have the better ability to make informed decisions about urban planning, conservation and climate adaptation,” Maron said.

This study was made possible by thousands of participants who provided observations through Project FeederWatch and eBird. These participatory science programs provide researchers with valuable long-term data on North American bird populations.