Hummingbirds are tiny and vibrant visitors to bird feeders, but considering they’re so small, researchers must rely on special means to study them.
Birds can be difficult animals to study, especially when it comes to tracking their movements. Unlike deer and bears, which can be fitted with heavy GPS collars and tracked via satellite, birds require smaller, lighter tracking devices. If birds are fitted with a tracker that’s too large or too heavy, it can make flying difficult, or even prevent them from flying altogether.
In some cases, like with hummingbirds, there are no GPS trackers small enough to safely attach to these species. So, researchers rely on another method to track these small flying critters: lightweight identification bands.
Lisa Young and Terry Tolbert are part of the Hummingbird Monitoring Network, where they spend much of their time capturing Utah’s hummingbirds, often in front of an interested crowd of people, and attaching numbered ID bands to their legs.
“We band every two weeks at three different stations while hummingbirds are in the area. Right now we're in migration season. We're looking at different things like population levels with resident birds, and also migrating individuals and some of their characteristics,” Young said. “One of the really neat things about banding birds is if you catch someone else's bird, or someone catches your bird, and then they document the band number each bird receives…it's an individual unique number that they get, so we can kind of track it if someone else gets the birds. Each band has a letter and then five numbers.”
Madison Lawrence, a previous bander with the project, explained that hummingbird bands are so small that instead of coming pre-made like most bird bands, hummingbird bands have to be made on site.
“They come in a long metal strip. And we have a couple of sizes here, and the smallest comes at 5.4 millimeters. That's pretty small. We have this chopper, and then once we have those chopped into sizes, we bring it over to this clamp. I don't know you call it…a metal clamp, and you just slide in there and clamp it down, and then that's basically it,” Lawrence said.
Considering hummingbirds are so small, special care is taken to make sure the birds aren’t harmed when being banded.
“So I'm going to measure her leg. The most important thing is the health and the safety of the birds as we collect that data that we need,” Young said. “And the pliers are specially made so that they exactly correspond to the band size so that there’s no injury to the bird, it will only close to the correct size that is measured.”
Young said even though hummingbirds are small, the birds they’ve banded sometimes travel quite far.
“The farthest that one of our rufous hummingbirds has been British Columbia, and all the way down to near Tucson in the Chiricahuas. That's quite the range,” Young said.
In addition to attaching a band to the hummingbird’s leg, Young spends some time examining the bird’s feathers for wear, measuring the length of its bill, and weighing it. To my surprise, she also pulls out a drinking straw and uses it to gently blow on the hummingbird she’s holding.
“So birds don't have feathers on the abdomen, the breast and the neck,” Young explained. “So I'm gonna see how much fat she has to see kind of her condition for migration.”
She blows on the bird again, pushing aside its feathers and revealing little yellow pockets of fat that show through its delicate pink skin, and then calls out a number indicating the amount of fat on the bird for a volunteer to write on a data sheet.
Hummingbirds have evolved hovering flight, which allows them to hover near flowers to easily drink from them. Young explained that they have other adaptations too, like their long beak that comes equipped with an extra-long tongue.
“Hummingbirds have really long tongues because you know some of the flowers that they drink from are tubular shape. And so to account for that length, their tongue actually goes out the back of their head and up their skull. So when they drink, you'll see their head bobbing because the tongue is sliding in and out of location on their skull,” Young said.
While hummingbirds are too small to track with more sophisticated technologies, researchers like Young can still learn a wealth of information and share their enthusiasm about these fascinating and vibrant birds with a simple identification band.