The name “brown creeper” sounds creepy, which is reason enough to write about this species for Halloween. Although brown creepers are year-round residents in Maine, they are seen more often once the leaves fall. Creepers also forage over a greater range of habitats in the offseason. They can pop up anywhere, so Halloween is a particularly good time to look for creepy creepers.
The tree creeper family contains 10 species worldwide, but the brown creeper is the only North American member. It ranges over a vast expanse from Alaska to Newfoundland to the elevations of Central America. Most other members of the creeper family are Eurasian birds of the northern forest, but one species creeps down into sub-Saharan Africa. All are small and brown. All have thin, down-curved bills that they use to probe under bark for insects and spiders. Creepers supplement their insectivorous diet with small seeds and vegetable matter.
Brown creepers are nonmigratory, though they will move to lower elevations in a harsh winter or wander when food supplies dwindle. Their brown coloration and mottled pattern strongly resemble the bark under their feet, so they are usually heard before seen. Fortunately, they’re noisy. They frequently whistle a reedy “seet” as they forage, calling attention to themselves. The sound is similar to call notes made by golden-crowned kinglets and white-throated sparrows, but it is slightly longer and reedier, dipping faintly in pitch as it finishes. Once the bird is heard, it is simple to find because it is likely to be creeping mouse-like up a tree trunk where the motion is easily detected.
Brown creepers aren’t great flyers, so they rely on their camouflage to save them from predators. When threatened, they will freeze against the tree trunk, even spreading their wings in order to better blend with the background. They will remain motionless until the threat has passed.
Unlike nuthatches, brown creepers can only ascend a tree. They hop up the trunk, with both feet letting go at each leap — a strategy that prevents a downward movement. They also have stiff, spiny tails that they use to brace against the rough bark, which would be a useless attribute in a head-first descent.
Once a creeper has reached the top, it will fly to the base of the next tree and begin the spiral ascent again.
Though I suspect they raise a family in my yard, I’ve never seen a brown creeper nest. Most people haven’t. It took naturalists more than a century to figure out that creepers suspend nests behind loose flaps of bark against the trunk of large trees, blending color and texture into virtual invisibility. Such an elaborate nest can take a week or two to build, with the male delivering materials and the female handling the construction. Brown creepers use sticky stuff, such as spider egg cases, to glue the bits and pieces together. Some nests are so elaborate that they have an entrance and an exit. Given that they are limited to climbing upward, they enter from the bottom and exit from the top.
The typical nest contains four to eight eggs, and creepers attempt only one brood each year, starting early. I usually hear their ethereal little song when snow is still on the ground. To me, it’s the tinkly song of a silvery bell. To others, it’s “see-see-see-sisi-see.” I like my version better. Creepers are intensely territorial, and they sing as much as they must in order to protect a territory of up to 15 acres. Courtship consists of chasing each other, fluttering wings, and exposing their white underbellies. The male continues to bring food to the female until the eggs hatch, then both mates raise the young together and remain a pair for several weeks after the kids are gone. Eventually, the territorial instinct and family bonds diminish. In late summer, unrelated creepers may roost and forage together. Brown creepers often move around with foraging flocks of golden-crowned kinglets, chickadees and nuthatches, appreciating the safety in numbers.
Brown creepers have been known to visit feeders, especially for suet, but I’ve never seen it. Theoretically, it might be possible to attract them with suet or peanut butter smeared into a tree trunk. That seems like a lot of work to me. If I want to see one, I just take a walk down my road and listen. It’s usually not long before I exclaim, “Jeepers, Creepers.”
Bob Duchesne serves as a Maine Audubon trustee and vice president of its Penobscot Valley Chapter. Bob developed the Maine Birding Trail, with information at www.mainebirdingtrail.com. Bob can be reached at firstname.lastname@example.org.