If you should see some movement on the bark of the tree, it will not be your eyes playing tricks, but a small bird hunting for an insect or spider hiding in the bark. The Brown Creeper is a fairly common bird within is range in the lower forty-eight states and Alaska. This small family of birds has only nine members in the world and only one species in North America. Creepers are very well camouflaged to blend in with tree bark; only movement will give away his presence.
Roughly five inches in length, much of which is its tail, this small bird is not well known among non-birders. The bird’s profile is slender including a relatively long tail with barbs on its tip to allow the bird to prop itself against the bark much like a woodpecker uses its tail. The upper plumage of a Brown Creeper is brown streaked while the underside is white. Some variation with the underside plumage occurs in birds on the west coast and Southeast Arizona. These birds are more buffy beneath.
The creeper’s bill is long and curved like a wren’s bill. These long, slender bills are designed to probe into tiny cracks and crevices in tree bark. The thin bills also allow the birds to extract the insect from its apparent safe hiding place. In teaching how to identify birds, I recommend starting with bill size and shape as indicators of what the bird likely eats and hunts.
Knowing the creeper’s behavioral habits can be very helpful in identifying this elf. His movement is always upward and he generally works all sides of a limb while foraging for food. After reaching the apex of his climb, the creeper flutters down to the base of a nearby tree and resumes his upward movement. Nuthatches, another group of bark hunters, more often work down the tree trunk or limbs. Warblers, particularly the Black and White Warbler, appear to walk tree trunks and limbs rather than scoot over the bark in short intermittent movements. Many of the wren species also forage for spiders and insects in the bark, but not in any consistent pattern.
Brown Creepers are winter residents in our riparian habitats along river and creek bottoms. They can be solitary, but more often they will form small flocks with titmice, chickadees, warblers, kinglets, nuthatches and other insect foragers. Small birds tend to form flocks in the non-breeding season as a way of feeling more protected in larger numbers rather than being solitary.
Hearing the bird’s call may be the best way to know of its presence, because the birds blend in so well with their surroundings. Their call is a high pitched “seee.” Golden-crowned Kinglets also have a similar, high pitched call. These calls are so high pithed that they can be difficult to hear. Especially if background noise of wind and sounds created by leaf movements interferes.
Some years we do not see large numbers of creepers, but I was encouraged this week when I saw one working the pecan trees along my creek. My experience has been that the creepers are not skittish when approached. I have also noted that well camouflaged birds and animals who rely on this form of protection often allow close approaches.
Many of you may not have heard or seen Brown Creepers, but be vigilant for them, if you have large trees in your yard or have woodlands on your property along a creek or river. When a flock of small birds shows up, scan the trunks and limbs of the large trees and look for movement. You might be treated to a pleasant surprise by finding a Brown Creeper.