How on earth do you band a hummingbird?
It is a violation of federal law to catch a hummingbird unless you are a licensed bander. In fact, in addition to state and federal banding permits, hummingbird banders are required to undergo specialized training before working with these tiny birds. However, the basic approach is much the same as with any bird, and hummingbirds, despite their size, are not as fragile as one might assume.
The bird may be caught in an extremely fine mist net or a simple wire cage trap baited with a feeder. The bands, each of which are handmade by the bander using thin metal sheets supplied by the federal Bird Banding Laboratory, are printed with an alpha-numeric code unique to that bird. The bands are, obviously, extremely small; it takes 5,500 to weigh an ounce. The band is applied to the lower leg with a special pair of needlenosed pliers with a precisely milled hole in the jaws, which forms a perfectly round band. Proportionately, the band weighs about as much on the bird as a man's metal wristwatch weighs on him - it is not a hindrance at all.
Once the bird is banded, it is aged, sexed, a series of measurements are taken with digital calipers, and the hummingbird is weighed. (Most weigh 2.5-4.5 grams; a penny, by contrast, weighs 2.6g.) Then the bird is quickly released, none the worse for the experience. The band remains on its leg for life, so that if it is encountered again, its movement, life span and other critical information can be learned. Despite its small size, the number code on the band can sometimes be read with binoculars while the bird is perched at a feeder.