MARKING BIRDS WITH ALUMINUM AND COLOR BANDS
Every bird that we capture for our research (like the Blackpoll Warbler pictured here) receives an aluminum band. On the aluminum band is a unique 9-digit number, printed in tiny font, that allows anyone who recaptures the bird to ascertain its identity and history. Without recapturing him, you wouldn’t know how old he is or where he was initially captured, and you wouldn’t have access to any other data collected by past research studies.
That’s where color bands can be useful. Color bands are small, lightweight (<0.1 g), plastic colored-markers that attach to a bird’s leg along with the bird’s aluminum band. The placement of the aluminum band, and the colors and order of the color bands, serves as a unique ID that can be read without having to recapture the bird. Banded birds usually have one aluminium band and up to three color bands like the Grasshopper Sparrow pictured below. We use very simple colors for the plastic bands: green, red, blue, yellow, white, orange, and hot pink.
HOW DO I READ COLOR BANDS?
It can be challenging to read the color combo on a moving bird–especially a Song Sparrow in the middle of bush–but that’s half the fun! It’s easy to get the top band confused with the bottom band and to reverse the left and right legs–especially if you see the bird from both the front and the back. Therefore, it’s best to describe the aluminum and color bands’ placement using the bird’s legs. For the Grasshopper Sparrow to the right, one would say that he is marked red over aluminum on the bird’s right leg; white over blue on the bird’s left leg.
TIPS FOR READING COLOR BANDS
- Take your time, and sketch or write down the colors and their placement while you observe them.
- A scope can be really helpful, but binoculars will more than suffice.
- The aluminum band appears silvery in good light, but it can look whitish in low light.
- Be aware: sometimes birds are marked with two bands of the same color on the same leg.
- The most common mistake: confusing the bird’s left and right legs when reporting the colors.
- In low light, the following colors look very similar: red/orange, green/blue, white/yellow.