Brown Creepers –insect-eating, bark-gleaning, little brown birds — are occasionally spotted as they circle their way upwards around and around a tree trunk, probing under bark with their thin, curved beaks for their next meal. Because they are so well camouflaged it is easy to miss them. Your chances of becoming aware of their presence are increased if you become familiar with the high, thin but surprisingly rich song males sing to establish territories on their breeding grounds this time of year. Although they continue to sing through the nesting period until their young have fledged, male brown creepers are most vocal early in the season, when they are staking out their territory. You can hear their song by going to http://www.allaboutbirds.org/guide/brown_creeper/sounds and clicking on “sound.”
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Can you find the brown creeper that’s on the trunk of this black cherry tree? This is cryptic coloration, a form of camouflage in which an animal blends into its environment, at its finest. A forager of insects and spiders tucked away behind and in the crevices of bark, the brown creeper starts its search at the base of a tree, climbing upward and often spiraling around the trunk until it nears the top. It then flies to the base of a nearby tree to begin the process again. As W.M.Tyler wrote in 1948 in Bent’s Life Histories of N.A. Birds, “The brown creeper, as he hitches along the bole of a tree, looks like a fragment of detached bark that is defying the law of gravitation by moving upward over the trunk, and as he flies off to another tree he resembles a little dry leaf blown about by the wind.”