wren, small, plump perching songbird of the family Troglodytidae. There are about 60 wren species, and all except one are restricted to the New World. The plumage is usually brown or reddish above and white, gray, or buff, often streaked, below. Wrens are similar to sparrows but have longer, slender bills and usually perch with their tails cocked straight up. They are valuable insect destroyers. Among the best singers are the canyon, Carolina, and winter wrens. Most wrens nest in natural holes and cavities; house wrens, which range over most of the United States and S Canada, will nest in boxes built for them and in crannies about dwellings. Also found in North America are the cactus, rock, and marsh wrens. The common European wren is a winter wren. Wrens are classified in the phylum Chordata, subphylum Vertebrata, class Aves, order Passeriformes.