Of course, I'm not talking about a tree-climbing pervert, I'm talking about the Brown Creeper, a small "beetle-shaped" insectivore that is wonderful adapted to life on the vertical, exploring the cracks and crevices of tree trunks and branches. Its tail feathers are stiffened like a woodpeckers to provide a support it can lean back down on, and its compact body shape keeps its centre of gravity close to the trunk. Its toes are not organised like most woodpeckers, with two backward facing toes, but rather in the style of most songbirds, with three forward facing toes and one backward facing toe. However the back toe has been equipped with an elongated claw to facilitate its life clinging to bark. Its bill is long, slender and curved to allow it to efficiently extract insects from the cracks and crevices as it explores. The upper-parts of the Brown Creeper are a dull brown in colour, mottled with white, creating an incredible cryptic effect where the bird simply blends in the bark is it moves about.
If you sit and watch one you'll, you can easily notice a pattern to its behaviour. It will fly to the base of a tree and then slowly work its way up the tree, picking out insects along the way. When it gets up high, rather than working its way back down again, as the Nuthatches can often be seen to do, it will instead fly to the base of a different tree and start the cycle all over again. It is a captivating bird to observe and listen to, a real treat to come across when walking through the woods, and one you can see surprisingly often if you stop and look. They are easily missed, but if you live in North American, they are probably found in your local patch of woodland.