A female cardinal bites the finger of Princeton University grad student Trey Hendrix as he holds her moments before release in April.  Hendrix had gently removed the cardinal from a mist net used to capture birds for banding or other research projects. AP Photo/Carolyn Kaster

One of my favorite fall memories is participating at a bird-banding station when I was a college student in Baltimore in the late 1970s. The banding station was located at a park on a peninsula jutting out onto the western portion of Chesapeake Bay. This point of land beckoned to southbound migrants seeking landfall as they completed a nocturnal migratory leg over the Chesapeake.

We captured the birds using mist nets. Our nets were 10 meters long and two meters high. Each net has several lines running the length of the net that support loose pockets. The thread of the net is thin and difficult to see. Birds fly into the net and softly land in one of the pockets with their head and wings lightly tangled.

At this banding station, we were running about 20 nets, spread out along the park trails. We opened the nets before sunrise and monitored them regularly so that a bird would be in the net for 15 minutes at the most.

The banding crew then has the responsibility of removing the birds by simply freeing the wings and backing the bird out of the pocket. Some birds like sparrows and warblers are easy to extract, requiring only 10 or 20 seconds for a skilled bander. Some birds like cardinals and grosbeaks show their displeasure by biting a finger hard enough to make blood flow. Chickadees are among the most difficult to remove because they wrap their long toes around multiple threads. One has to free the feet before you can tend to the head and wings.

Most birds were captured by eight o’clock or so, but we generally kept the nets open until 10 or 11 a.m. Fifty to 100 birds would be a typical catch. I remember one morning when we had a huge fallout of birds. As we were opening nets, a cry went out “close the nets.” In a matter of 10 minutes, we had caught over 100 white-throated sparrows in just a few nets. Opening all the nets would have overwhelmed us.

Once extracted, a bird is put into a small cloth bag and taken to the banding table. Each bird is fitted with an aluminum band bearing a unique nine-digit number. The bands are provided by the Bird Banding Lab, a federal agency in the U.S. Geological Survey. With the bird in hand, a band is opened, placed around a bird’s lower leg and then closed with specially made pliers. The bird is then released.

At the very least, the species, sex and age of the bird is recorded along with the location and date. Banders may record other data as well such as weight, fat load, wing length and molting status. The species, sex and age data along with the band number are reported to the Bird Banding Lab.

The Bird Banding Lab serves as the central repository for all banding information. If another bander captures a previously banded bird or if someone finds a dead bird with a band, an email to the Bird Banding Lab will allow the observer to know when and where the bird was banded. The Bird Banding Lab also notifies the original bander that one of her/his birds was recaptured.

To band native birds, one must obtain a banding permit, possible only after extensive experience in assisting a licensed bander. My experience at that station qualified me to get my own master bander permit. I regularly banded birds in my research projects before I retired.

Because pigeons or rock doves are not native species, one does not need a banding permit to band them. As a result, pigeon fanciers often band their birds with particular color bands so they can be easily identified. These band combinations are not regulated by the Bird Banding Lab so one must consult pigeon fancier clubs to try to track down the owner of a sighted racing or homing pigeon.

In the next column, we’ll explore the value and limitations of bird banding in learning about our feathered friends.

Herb Wilson taught ornithology and other biology courses at Colby College. He welcomes reader comments and questions at whwilson@colby.edu