“What wild creature is more accessible to our eyes and ears, as close to us and everyone in the world, as universal as a bird?” - David Attenborough

To the dismay of many naturalists, bird populations are declining across the eastern United States. Many factors are contributing to the decline, including habitat loss and mercury pollution. 

Besides adding color to our world and a chirping melody to our morning routines, birds keep forests healthy by scattering seeds, pollinating plants, and controlling pests. The U.S. Forest Service studies birds and their habitats to understand why different species thrive in some places and not others. In Irvine, Pennsylvania, a dedicated group of citizen scientists—led by Forest Service biologist Scott Stoleson, PhD—helped collect data that led to a surprising discovery about the preferred post-breeding habitat of forest birds.

“I had come up with this project idea but didn’t have funds to hire assistants,” says Stoleson, who works at the Northern Research Station. “So I asked some local folks if they’d be willing to help band birds, and most of them were very excited about it. Some have been helping me for 13 years.”

The study focused on the time between summer nesting and winter migration—a period of a bird’s life that is not well studied. Volunteers gathered birds from mist nets, banded them, and recorded data including molt progression and body condition. 

The data suggests that after their chicks fledge, many forest songbirds relocate to clear-cuts where vegetation has begun regenerating rather than staying in mature forests. Clear-cutting involves uniformly cutting down most or all overstory trees. Without mature trees creating shade, understory plants can proliferate in these gaps, and many shrubs produce large crops of fruits and berries in late summer. Thus, although many songbirds require mature forests to breed, some of those same species are showing signs that clear-cuts are a preferable habitat after breeding season is over.

In fact, some of the forest birds appeared to be in better condition in cuts rather than mature forests, and 32 out of 33 bird species were caught in higher numbers within areas of clear-cutting.

"Humans have really changed the nature of mature forests in the Northeast," says Stoleson. "Natural processes that once created open spaces even within mature forests—such as fire—are largely controlled, diminishing the availability of quality habitat." 

About his work with citizen scientists, he says, “Banding birds or netting birds can be very time-consuming, so the more volunteers I have, the larger sample size I can attain and the more rigor the science has.”

If a net catches 30 birds or more, it would be overwhelming for only 1 or 2 scientists to handle, so having volunteers around is especially important when stormy weather becomes dangerous to the netted birds.

One of the project’s volunteers, Don Watts, is also a federally licensed bird bander who recently retired from the Forest Service. He confirmed that having more hands available to extract birds from the nets helps to minimize the risk of harming them. 

“We use these polyester nets that are 8-feet high, stretched between poles,” he said. “The birds can’t see the net, so they fly right into it and drop down into these 4-6” pockets in the net that they can’t get out of. We check the nets every 20 to 30 minutes and get the birds out, collect data, and band them. We can’t wait too long or else chipmunks or weasels could come along and eat them up. This keeps you busy when you have 8 nets up at once.” 

Other citizen scientists came from Penn State DuBois, where wildlife educator Emily Thomas volunteers with her students to teach them bird monitoring and banding. The Jamestown Audubon Nature Center also contributed many volunteers who were vital to the project’s success. 

As Stoleson pointed out, humans are altering the size, quality, and quantity of forest habitat in the Northeast. His research findings make it easier to understand where and why conditions are favorable to birds—and therefore where to focus conservation efforts. 

Stoleson’s mist netting study is completed, but he expects to be using more citizen science in the future. “As budgets shrink or at best stay stable while costs increase, we’ll find ourselves utilizing private citizens for help,” he says. “And it’s been my experience that many people are eager when they learn something in return.”

Research Publications:
Stoleson, Scott H.; Larkin, Jeffery. L. 2010. Breeding Birds Of Pennsylvania: Forest Communities.