For years, MSRW has been capturing owls and other raptors and ‘banding’ them. Although many folks probably have a vague idea what that means, I thought this would be a good chance to go into details. Banding, or ringing as it is called in Europe, is putting a metal band with a unique number on the leg of a bird. At MSRW, and at other banding stations, the metal bands we use are distributed by the federal government for the sole purpose of scientific research. Information that we gather at the time of banding, such as date, location, age and sex of the bird, and various measurements, are all submitted to the Bird Banding Lab, which is a division of the US Geological Survey. Banders are required to have federal and state permits in order to band a bird. In order to receive a permit, a bander has to prove that they are trained to safely handle and band a bird, follow ethical guidelines, and have a valid research question that they are trying to answer with the banding project.
The first step in banding is to determine the correct band size for the bird in hand. Bands come in all sizes and so we use a ‘leg-sizer’ card (see photo below) to determine the band size that will be the best fit. In the case of Northern Saw-whet Owls, we know that they will require either a size 4 or size 3A band and so those are the two slots that we test on our owl in hand.
We use a ‘butt-end’ style of band on Northern Saw-whet Owls and smaller birds. These bands just open and close along a slit in the ring. As you can see from the photo, a saw-whet band is not very big. But then neither are saw-whets! We use a modified pair of pliers to open and close the band safely around the bird’s leg.
Larger owls are fitted with a ‘lock-on’ style band because they would be able to rip off the standard ‘butt-end’ type of band. With this band, we crimp the metal tab to create a ‘lock’ that strong bills can’t break. Long-eared Owls take a size 5 (males) or size 6 (females) lock-on band, while Barred Owls take a size 7B and Great Horned Owls take a size 8 or size 9. A third style of band, the rivet band, is used on larger raptors, such as eagles. As the name implies, the side tab is secured with rivets, which the eagle hopefully can not remove.
As you can tell, banding wild birds is considerably more complicated than banding the chickens in your yard! MSRW lead and master banders have years of experience and have each banded thousands of raptors. Even so, we are careful when banding each and every bird to ensure the bird’s safety and to learn more about their life histories and migration.
Season Totals (March 15 through April 15):
Northern Saw-whet Owl: 91 (84 new, 7 recaptures)
Barred Owl: 1