Natural Connections: An in-depth look at bird banding
"The location-based information made available by a band teaches us about birds’ migration habits, such as if they tend to summer and winter in the same area year after year and the dates of their migrations," writes Olivia Rataezyk.
Editor's note: Olivia Rataezyk is from Seattle, Washington and studies biology at Kenyon College in Ohio. On campus, she divides her time between a research lab studying birds (her favorite animal) and her college’s art gallery. Olivia just finished her tenure as a summer naturalist intern at the Cable Natural History Museum.
CABLE — The sun was hot in the Moquah Barrens as I trekked up a hill to meet Jim Bryce and watch him band birds as part of my Wisconsin Master Naturalist Volunteer Training. I had some experience with this process through my school; I work in a lab that occasionally catches and bands birds in our area.
As we watched Jim carefully arrange small metal bands, a handheld scale, a ruler and pliers on his table, I thought back to my last experience with bird banding. On a warm morning in May 2021, my lab mates and I loaded into my friend’s minivan with the necessary supplies. At our research site, I helped hoist a mist net between two tall poles. About the size of a volleyball net, mist nets are made of such fine filaments that they disappear into their surroundings.
Within a few minutes, birds started flying into our net, and we began extricating them and putting them into small, cloth bird bags for transportation back to our lab. At a small table, we measured their weight as well as the lengths of their wings, beaks, legs and tails using tools similar to Jim’s. This data became the foundation of the project’s database. We also slipped simple plastic bands onto the legs of each bird. Each one got a unique combination of up to three colored bands that became the bird’s “name.”
The goal of this study was to figure out if the GPS tags that researchers often attach to birds have any impact on their flight or fitness. Each individual was first filmed without a tag, then fitted with a homemade mock-tag made from aluminum foil and electrical tape and filmed several more times over 10 days. We measured how each bird’s flight changed as they adjusted to wearing the extra mass and also tracked their body condition. The colored bands allowed us to easily identify each bird so that we knew who we were filming and measuring. Using the data we collected, we determined that these tags temporarily decreased flight velocity in our subjects.
In the Barrens, we followed Jim around to his three mist nets to watch him extricate the birds. At his ancient folding table, he talked us through the process as he measured each bird and selected a band sized for their species. Instead of color bands, Jim uses tiny metal bands stamped with unique numbers. The U.S.G.S Bird Banding Laboratory issues these bands to certified bird banders and manages banding data for future reference.
Metal bands rarely fall off, so unless the numbers get worn to the point of illegibility, the band will be useful indefinitely. As he wrote down band numbers in his worn logbook and used special pliers to close the band around a bird’s leg, Jim talked about how rare it is for him recapture a banded bird. Each one holds a special place in his memory.
Recaptures may be rare, but they are a main goal of the U.S.G.S. banding project. When a banded bird is recaptured, their new captors can check the band number to discover past information, like where and when the bird was first banded. Birds are sometimes caught across widely varied locations.
Or, just as tellingly, birds can be recaptured in the same location. That’s happened for Jim twice at this site. Both a male clay-colored sparrow and a male yellow warbler found their way onto his banding table two years in a row. Each of them had migrated thousands of miles over many months and then returned to the same territory for another breeding season.
The location-based information made available by a band teaches us about birds’ migration habits, such as if they tend to summer and winter in the same area year after year and the dates of their migrations. Recaptures can also provide body condition information that creates a partial record of a bird’s health over the course of their life.
The color bands I worked with in the college lab wouldn’t be useful for the broad mark and recapture studies Jim was contributing to, but they are useful for their own reasons. They allow us to work with large groups of temporarily captive birds while making it easy to keep track of the data we collect. That study gave us more information about how GPS tags — yet another way to study birds — impact flight and health. Taken together, all of these different ways to mark and study birds give us valuable tools to answer questions about bird behavior.
I hope you enjoyed learning more about banding as much as I did. I think this is a fascinating practice, which is especially useful since this fall I’m headed back to school where I hope to continue to do bird research this year!
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