The Buzz of Bird Banding

A Black-Capped Chickadee (Poecile atricapillus) held in the hand of a wildlife biologist.

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There is nothing quite like the feeling of holding a wild bird in your hands. As a certain kind of stillness sweeps over, you notice your heart beating a little faster in your chest. A heightened sense of intimate privilege and incredible responsibility for well-being of the delicate creature resting in your palm flows through you. A symbol of freedom, itching to fly again, their bodies are strangely pliant as you twist your wrists to look at their undersides. Many are quiet, only looking at you with their heads cocked to the side. Others will chirp at you until released, unharmed. Birds have always felt out of reach, but holding one now makes you realize just how fragile they are. You release it and watch it fly back into the woods, then let out a breath you didn’t realize you were holding, your body still humming.

I followed a group of biologists and volunteers in Glacier National Park before the sun had breached the horizon down an unmarked trail. This group of early birds manages the Park’s MAPS station. Nationally started by the Institute for Bird Populations (IBP) in 1989, MAPS stands for Monitoring Avian Productivity and Survivorship. There are over 300 active MAPS stations in the U.S., Canada, and Mexico that do the same routine up to every ten days in the summer.

Each station puts up ten delicately threaded nets in areas songbirds are likely to fly through. After the first net is up, a 30-minute timer starts, and the group waits. Once the alarm goes off, the team makes the rounds to check each net for birds. The birds are processed and documented to help researchers keep track of them in the future and to contribute to the MAPS database. This cycle goes on for six hours. The earlier the sun is up, the earlier they start.

Wildlife biologists look through reference materials and data sheets while banding birds during the MAPS program.

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They are led by Lisa Bate, a supercharged wildlife biologist for Glacier who started the park’s MAPS station. I try to keep up with her as she moves from net to net, pushing through grass and wildflowers that go up to her waist. She is buzzing with energy, despite the fact that—as she later reveals—she has been awake since 2:00 am. While I’m distracted by the sunrise and meadow surrounding us, her mind is honed in on one thing: the birds.

“With this program, we can really learn about the survivorship of the adults and juveniles and learn if the populations are increasing or decreasing and where that is occurring. Bird numbers are declining for a lot of species and it’s important to track what’s happening, especially in a national park because they’re undeveloped and protected from extractive industries.”

—Lisa Bate, Glacier National Park Biologist

A Gray Catbird (Dumetella carolinensis) is evaluated by a wildlife biologist.

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Back at a folding table in the middle of the survey site, a Gray Catbird is examined. Its call sounds like an electronic cat’s meow and it’s one of the more vocal birds the group has caught. The Catbird is giving the biologists a piece of its mind by complaining about the hold-up with squawks and occasional pointing pecks at their fingers. The surface of the table is covered in reference charts, data sheets, a scale, and a book on molting patterns. The meows are ignored as data is quickly gathered but the bird’s leg is bare, meaning it hasn’t been captured by a MAPS station before. After measuring its leg, a silver band with a unique serial number is selected and secured onto the Catbird like a bracelet. The number is documented along with other information about the bird’s feathers, ensuring its health and age will be tracked for years to come. Then the bird is released.

When the rest of the group isn’t checking or untangling nets, they’re gathered around watching the birds - while occasionally digging into the home-made cookies Lisa brought. The sun basks everything in early light as the rest of the team is still a little loopy from sleep deprivation, including myself, which makes it all feel dreamlike. Bird after bird zips out of the nets and onto the processing table. Yellow warblers, golden-crowned kinglets, and song sparrows watch their handlers curiously while they list off measurements. Their feathers can reveal species, age, and sex. A measured turn of the wrist from experienced handlers shows the bird’s bellies, smooth and oblong. Gently blowing the feathers aside reveals a brood patch: a fleshy patch of featherless skin used to incubate eggs. It feels like seeing a bird naked and I cringe a little, but the birds don’t seem embarrassed. Only a few chirp at the puff of air ruffling the small feathers out of place. Their bodies are calm but still thrumming, a natural feature of something so small and made to fly.

The male American Redstart’s (Setophaga ruticilla) black and orange feathers look quite different from the drabber olive and yellow females.

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“It’s exciting when you start recapturing birds you banded in the past year or birds that have been banded elsewhere,” Lisa said. “Our birds can be picked up in Costa Rica or Mexico. With that information, we get to learn where Glacier’s birds are traveling to.”

Traveling avians are a large portion of Glacier’s over 270 documented bird species, which includes raptors, songbirds, shorebirds, and waterfowl. The American Redstart is one of these travelers; breeding in Glacier around June and July and then flying to Central America for the winter. In the morning I’m there, the group catches two females with gray heads, olive-green backs, yellow patches, and pale-yellow sides. The most frequent bird caught in 2024 was the Swainson’s Thrush, which have a similar migration pattern to the American Redstart. Dusty-brown with pale bellies and speckled necks, their songs sound similar to trilling flutes, adding to the symphony of the forest. Glacier’s MAPS program has documented at least 80 songbird species since it started, with four new birds to their database added in 2024. Although these birds are small, MAPS helps them contribute to a cause much bigger than themselves.

Glacier National Park’s MAPS program documented 29 different bird species in 2024.

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The risk of birdsong quieting to a whisper hangs over our heads. According to the Cornell Lab of Ornithology, nearly 3 billion birds have vanished since 1970, showing an across-the-board decline of birds in North America. Each bird in the hand of a MAPS station biologist sheds valuable insight on these population declines, furthering hope that causes can be located and solved. Our palms are much bigger than the body of a songbird but feeling the beat of their hearts is a reminder that while they are resilient, they’re still small enough to be vulnerable to sudden changes in their habitats, food sources, and temperatures. With a flap of their wings, they could ignite passion in anyone who pays attention to the beauty of their feathers and how they ripple through nature.

Funded by Glacier Conservancy, Glacier’s MAPS is a product of a community caring about conserving wild places.

Read more about MAPS in Glacier:

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  Birds of a Feather

  By evaluating the condition of birds, feather by feather, scientists can get a better picture of the health of an entire species.

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  Taking Flight

  Since its liftoff, more than 1,200 MAPS stations have collected more than 2.5 million bird capture records. About 300 are active today.