Remember those leg bands that we put on birds so we can tell them apart? Getting them on the birds requires some specialized equipment. (Plus a permit! Do not try this at home!)

First, you need bands.

Size 0 (left) and size 1 US Fish & Wildlife aluminum bands

Color bands too, if you’re color-banding. My color bands haven’t arrived yet, so I don’t have a picture.

But wait: how do you know what size bands to use? Too-small bands won’t fit; too-large bands might slide down too far, over the bird’s foot, and prevent it from using that foot. So you need a leg gauge to measure each bird’s leg.

Leg gauge

You measure a leg by fitting the gauge slot over the widest dimension of the leg. For a junco, I might try 1C and find that the leg doesn’t fit; try 1, and it fits; try 1B, and find that there is extra space. Then I would choose a size 1 band.

In practice you often already know what size leg a species has. You can consult the Pyle guide, or ask your local bird banding station. It’s good practice to check, though, especially if your species has some variation. Juncos can be size 0, 1C, or 1, so I’ll be measuring each bird to make sure I choose the right size band.

To get the band on, you use banding pliers.

Banding pliers

These look scary, but they never touch the bird. First you insert the pin (the sticking-up bit) into your band and open the pliers enough to open the band. (Notice, in the picture of the bands, that they are all fully closed circles: you have to open them to fit them onto the leg.) Then you put the open band on the bird’s leg, and use the circle indents in the pliers to close the band in a perfect circle. We’re very careful about this, because an incorrectly-closed band—one where the edges don’t match up perfectly—can irritate the bird’s leg.

Just to be safe, we have one last tool: band removal pliers.

Band removal pliers

These look even more like a torture implement than the banding pliers, but they too are used on the bands, not the birds. If a band doesn’t close properly, you can use this to open the band and remove it. This way we make sure that we never let a bird go with an imperfect band.