Jeepers, Brown Creepers are creeping up trees all over the country! These small cryptic birds are common throughout the United States and are winter residents up and down the High Plains. But despite the fact that Brown Creepers are far from rare, it’s quite likely you’ve never seen one.
     It’s their sneaky way of moving around that makes Brown Creepers easy to overlook. They creep almost exclusively on tree trunks, flying to the base and traveling upwards on a spiral path. Once they get about halfway up the trunk, they fly to another tree’s base and start over.
     Creepers are related to nuthatches, another bird known to creep. But nuthatches travel over bark in any direction — up, down, or sideways. Brown Creepers only creep up.
     What nuthatches and creepers have in common is obvious when they take flight: both are small with stocky bodies, long bills, and short, rounded wings. They differ in the shape of their tails. Nuthatch tails are stubby, rounded fans; Brown Creeper tails are long and thin, and are used for support in the climb. From the way they move, you might think Brown Creepers were related to the woodpeckers, for they like woodpeckers use their tails as a third point of purchase on a tree.
      Another way they differ from nuthatches is in the shape of their bills, for creeper bills are curved — or, in proper bird-speak, decurved, which means curving downward. They use these thin curved bills like a set of tweezers to pluck out tiny insects and eggs from the cracks and fissures in the bark.
     Their coloring also helps them hide, as they are a mix of mottled brown and tan that renders them almost invisible against the bark. When they fly they reveal a cream-colored stripe on their wings that follows the curve of the wingtips, visible from above or below. They are light underneath, as nuthatches are, and the rump and tail-feathers show a red-orange color that is hidden when the bird is perched.
     Another thing they have in common with woodpeckers is the fact that they molt their tails — losing all but the central tail-feathers.
     In summer they eat insects and spiders, and tiny insect eggs. In winter their diet expands to include nuts and seeds — any little tidbit they can find in the furrows of a tree. According to the Sibley Guide to Bird Life and Behavior, “It is challenging for creepers to glean enough food to survive during cold winter days, when using energy efficiently is important.” Like certain other tiny birds, they often roost together in winter for warmth. It’s not uncommon for half a dozen creepers to share the same crack or crevice, huddling together to survive. When it warms up, they spread out to begin their solitary creeping after food.
     When breeding season comes, the female creeper spends a great deal of time building the nest, which is sometimes described as a “hammock.” This motley collection of bark, moss, feathers, and spider cocoons is slung across a crack or crevice, or behind a loose section of bark. Construction of the hammock can take the female creeper as long as a month.
     For me, Brown Creepers represent those many common birds we can live our whole lives around and never notice. Though their numbers may be small, they live wherever trees are found and go about their secretive lives beneath our very noses. Keep your eyes open and you may discover the Brown Creepers in your own neighborhood.