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What Do The Leg Bands Mean?

Dear Bird Folks,

I live on a pond where Mallards sometimes come into my yard to eat bird seed. Recently I noticed one male Mallard had two bands on its legs. I tried to attract him closer by sprinkling a little seed near the house, so I could read the numbers on the bands, but no luck. Oh well. Thanks.

– Amy, Hatchville, MA


You know Amy,

Ordinarily I wouldn’t have answered your note because you never asked a question. However, you brought up bird banding which is a very interesting topic, at least it is to me. And second, you live in “Hatchville.” How could I not write to someone from Hatch-ville? That’s the birdiest named town that we’ve had since last year, when we received a letter from a lady who lives in Birdbathburg. Ever been there?

Very few procedures have provided avian researchers with more information than the banding of birds has. The answers to the most commonly asked bird questions are based on information gathered by bird banders. What are the impacts of development, pesticides and hunting on bird populations? How long do birds live? Where do they go in the winter? Do they mate for life? Are my neighbor’s feeders stealing my hummingbirds? Without bands we wouldn’t have answers to any of these questions and we wouldn’t know how much we should glare at our neighbors.

The first person known to use metal leg bands was Henry the IV of France. His banded falcon disappeared one day while it was attacking a bustard (easy now). Henry’s falcon was found the very next day, but not in France. It was 1,350 miles away, in Malta, where it was spotted eating goat cheese and figs. Until that day neither Henry the IV, or any of the other Henrys knew that falcons had such range.

The first North American to use bands was our old pal John James Audubon. He tied silver threads to the legs of young phoebes and noted that they returned to the same neighborhood the following spring, where he promptly shot them. Maybe.

Today bird banding is much more than a guy tying silver threads on legs. It is an important data gathering tool that is regulated by the Interior Department’s Bird Banding Laboratory in Laurel, MD. All banders must be trained, licensed and have a degree in bandology.

Banders use a whole assortment of methods to catch birds, from traps to plucking babies out of nests. Songbirds and birds of prey usually “catch themselves” by mistakenly flying into carefully placed, and hard to see, mist nets. Flocking birds, like shorebirds and waterfowl, are good candidates for the dramatic rocket nets. Just as the name implies, net carrying rockets are shot over flocks of roosting or feeding birds, creating a noisy and stressful few minutes for both the birds and the researchers.

Once a bird is captured it is typically weighed, has its wings measured, plumage inspected for molting and parasites, and then is asked a series of personal questions. In addition, notes are recorded as to the date, location, and the bird’s age and sex. Recently another step has been added. In an effort to gain knowledge of possible avian flu carriers, captured birds are also swabbed. I won’t tell you what part of the bird is swabbed, but most of us would not want to be either the swabber or the swabbee.

After the paper work and swabbing fun have been completed, a numbered aluminum leg band is placed on the bird’s leg. The newly decorated bird then flies off, cursing as it goes. The bird’s collected info, along with its own individual band number, are eventually sent to the big computer at the Bird Banding Laboratory. Through the numbers on the band each individual bird can be either tracked for science or called in for jury duty.

Over the years Cape Cod has been at the forefront of bird banding, starting in the 1920’s with the pioneering work of Oliver Austin, then with the legendary Jonnie Fisk, and continuing today with the Museum of Natural History’s outstanding master bander, Sue Finnegan. The Mallard that is in your yard, Amy, was most likely banded by either the state or federal Fish and Wildlife services. They may have been trying to figure out which Mallards are permanent residents, which are migrants and which Mallards actually know where Hatchville is. If you are ever able to read the leg bands or if you ever find a band, either by itself or on a dead bird, report the numbers to the feds by calling 800-327-2263 or by punching up They will respond by telling you when and where that bird was first banded and what kind of company it has been keeping.

If you don’t ever see that Mallard again, Amy, don’t worry, it’s probably fine. It’s either migrating back north, nesting locally or has been called away for jury duty.