Introduction

The Carolina Wren is an energetic, generalist species that frequents homes and gardens, as well as wilder habitats. Found mainly in the eastern United States and Central America, it is most common in the southern United States where every patch of woods seems to be inhabited by this nervous, often shy permanent resident. A small bird with rusty upperparts, cinnamon underparts, a distinct white eye-stripe, and a loud and varied repertoire, it is more likely to be heard than seen. Males and females are identical in plumage, but males are often slightly heavier and have longer bills, wings, and legs.

Insects and spiders make up the bulk of this wren’s diet. Although they generally feed on or near the ground, foraging individuals sometimes climb trunks and branches like a creeper (Certhia) or nuthatch (Sitta). A strongly philopatric species, the Carolina Wren maintains territories and pair bonds year-round. Both sexes help build the nest, which is usually domed and within 1 or 2 m of the ground. In natural settings, individuals prefer to nest in open cavities, but around homes and gardens they often build in nooks or unused receptacles. Multiple nestings of four to five eggs are common, and three broods are sometimes raised in a season. Males contribute substantially to the care of nestlings and fledglings.

As climate has warmed, this species has expanded northward substantially since the late nineteenth century. Cold winters with ice and snow can have devastating effects on local populations, but they often recover within a few years. Although considerable work has been done on the vocalizations of this species, little has been published on other aspects of its biology. How strongly it competes with other wren species, for example, remains unknown. Classification of its subspecies needs clarification. And the apparent monogamous mating system of this wren warrants study; most wrens, including the House Wren (Troglodytes aedon), often sympatric with the Carolina Wren, are polygynous.