For the house wren, “survival of the fittest” is a take-no-prisoners proposition. With a wingspan of less than 6 inches and a body weight on par with that of two quarters, Troglodytes aedon makes up with aggression for what it lacks in size.
Back in the 1920s, the cavity-nesting songbird’s combative ways earned the species quite a reputation. Its harassment and fatal attacks on adult avian neighbors—exacerbated by the tendency of some bird-lovers to hang too many birdhouses in close proximity—were credited as a primary cause of nest failure among bluebirds, tree swallows, and chickadees. Even so, the species had its defenders. “Many birds are so free from special vices or virtues that their economic status is decided upon the basis of their food habits alone,” observed ornithologist Waldo Lee McAtee in 1926. “Were this true of the house wren, the species would receive a very high appraisal, for it is almost exclusively insectivorous, and that, too, in chiefly commendable directions.”
For gardeners intent on minimizing insect pests and cueing the spring soundtrack, the house wren has clear appeal. Easy to attract, it boasts a voracious appetite for beetles, caterpillars, and leafhoppers. An enterprising male will transform even an old boot or terra-cotta planter mounted on a fence post into a welcoming home—sometimes building several nests simultaneously as he courts prospective mates. As he labors, he chortles a complex tune, repeating it as often as 11 times every minute to establish and defend his territory. Females sing less often, chiefly in response to their mates.
Both sexes sport muted brown plumage with faint barring on their wings and tails, which they hold cocked perennially at attention. Their breeding range spans the continental United States and extends northward into Canada, making the species the most widely distributed of the order Passeriformes—or perching birds—in North America. They fledge one and sometimes two clutches—between 3 and 11 eggs at each go—before migrating to Central and South America for the winter.
House wrens thrive in hedgerows and woodland edges. To re-create such habitat in the suburbs, build a brush pile or two where the birds can forage safely for bugs and collect nesting material. While adults take new mates each season, they frequently return to territories they’ve inhabited previously.
Originally published in Organic Gardening Magazine, April/May 2014
Photo: (cc) JulianLondono/flickr