Brown creeper

Did You Know?

• Brown creepers forage by zig-zagging upward from the bottom of a tree trunk, then flying down to the bottom of another tree.
• They mainly eat small arthropods found in the bark, but sometimes eat seeds in winter.
• Both parents help feed the chicks and remove fecal sacs from the nest.

Description

The brown creeper’s upper body is brown with pale speckles, helping it blend in with tree bark, while its belly is white. It has a slender, slightly curved bill and a long, stiff tail that props it up as it climbs upward. Males have a bill that is a bit bigger than females’. This bird is smaller than a white-breasted nuthatch but larger than a golden-crowned kinglet. It measures 4.7 to 5.5 inches long, weighs 0.2 to 0.3 ounces, and has a wingspan of 6.7 to 7.9 inches. Its calls are very high-pitched, short, and often urgent, sounding like “see” or “swee.” The song follows a rhythm like “pee pee willow wee” or “see tidle swee,” using notes similar to the calls. In California, songs have four to nine syllables, except in the San Bernardino Mountains, where they have nine to thirteen syllables, all within the same two-second span. Because it avoids open edges, has camouflaged feathers, and uses high-pitched sounds, this species is often missed during surveys compared to other birds.

Distribution, habitat and range

Brown creepers are both migratory and year-round residents in North America. Their breeding habitat is mature forests, especially conifers, in Canada, Alaska and the northeastern and western United States, and they are non-breeding in the southern part of the United States. They are permanent residents through much of their range; many northern birds migrate to the southern half of the United States. Brown creepers have occurred as vagrants to Bermuda and Central America's mountains in Guatemala, Honduras and the northern cordillera of El Salvador. Since 1966 the brown creeper has experienced a yearly 1.5% population increase throughout the northeastern and northwestern (Pacific coast) regions of its range. The first breeding brown creepers in the Northwest Territories were detected in 2008, in the Liard Valley, which may be a result of northern range expansion. As a migratory species with a northern range, this species is a conceivable vagrant to western Europe. However, it is intermediate in its characteristics between common treecreeper and short-toed treecreeper, and has sometimes in the past been considered a subspecies of the former, although its closest relative seems to be the latter. Since the two European treecreepers are themselves among the most difficult species on that continent to distinguish from each other, a brown creeper would probably not even be suspected, other than on a treeless western island, and would be difficult to verify even then. Brown creepers prefer mature, moist, coniferous forests or mixed coniferous/deciduous forests. They are found in drier forests as well, including Engelmann's spruce and western larch forest in eastern Washington. They generally avoid the rainforest of the outer coast. While they generally nest in hardwoods, conifers are preferred for foraging. Breeding brown creepers generally require trees of a large diameter, whose deeper bark furrows support large amounts of bark-dwelling invertebrates such as spiders. They also require continual renewal of snags, with a preference for balsam fir in their New Brunswick breeding range. Brown creepers have been recorded breeding in the dry season (January–February) in Chalatenango Department, El Salvador, a behaviour unusual to insectivorous birds and shared in the region only by the golden-fronted woodpecker.

Conservation status

While brown creeper numbers have dropped across much of North America, Washington State appears to be an exception. There, the state's breeding bird survey has recorded a slight, though statistically insignificant, uptick since 1966. As is common with many of Washington's birds, the Cascade Range splits the species into two distinct subspecies. In Wyoming, the bird shows a clear preference for large, unbroken, mature forests of spruce, fir, or lodgepole pine. This makes it susceptible to logging, climate shifts, or the conversion of these trees to Ponderosa pine, though Wyoming does not list it as a major concern. In New Brunswick, even moderate forestry harms the species. Local conservation work there prioritizes preserving unmanaged patches within mature forests that offer plenty of trees and snags. The ivory-billed woodcreeper has been seen pulling brown creeper chicks from their nests and discarding them.