Spring 2000 Table of Contents

Who's That?

Backyard birders may wonder “Who’s that?” when tiny, quick-moving members of the Wren family arrive on their property in the spring. These assertive, noisy birds hardly fit our definition of a reclusive troglodyte, but they actually make up the family Troglodytidae. One Native American term for wren translates to “big noise from little size.” The Anglo-Saxon word “wren” carries a connotation of lasciviousness, perhaps because of the males’ polygamous behavior.

Whatever we call them, wrens are fun to get to know, especially since some species readily use or even prefer human-made nest boxes.

Washington is home to six species of wrens. Three are particular to special habitats not usually found in backyard sanctuaries, as noted in their common names -- Marsh wren, Canyon wren, Rock wren. But the other three are relatively common in the open woods, dense shrubbery, or gardens that many backyards include.

The Winter wren (Troglodytes troglodytes) is the smallest at about 3-1/2 inches in length. It also has the shortest tail, a mere stub in comparison to other birds but like most wrens it cocks that tail in a perky upright position. Also like most wrens, it has a chunky body, slender and slightly curved bill for insect-eating, and basic brown plumage.

Along Washington’s coast, the Winter wren is a year-round resident. But in the rest of the state it moves in for spring and summer breeding and migrates to the southwest for the winter. (Perhaps southern birders created its common name?) The male arrives in April, usually a week or two before females. He busily builds several nests, usually low in dense brush, often streamside. A mating female chooses a nest, and then the male shows the remaining nests to another female for a second mating.

Most common is the House wren (Troglodytes aedon), a spring and summer resident of Washington that winters in or near Mexico. Its larger size (4-1/2-inch length) is gained mostly in its longer tail. Otherwise it looks very similar to the winter wren, perhaps with less prominent barring on the belly.

Its common name comes from its nesting affinity for birdhouses, or house porch lights, cans, hats, boots or nearly any cavity-like, man-made item that appears to provide some measure of security. House wrens have even been known to nest in the pockets of pants hanging on a clothesline!

The early-arriving male House wren cleans out a nest site, which may include destroying another bird’s nest and nestlings, then builds a foundation with twigs. He repeats this in several sites within his half-acre or so territory, all the while warbling loudly. When a female arrives to inspect the sites, his song changes to a high, squeaky one and he performs wing quivers and flutter flights to entice her. When she chooses a nest, she lines it with soft grass and feathers. The male brings her food while she incubates eggs.

House wrens often have a second brood, sometimes with the same mate but sometimes not. The male repeats his nest cleaning and building and courting rituals, and the female leaves her first brood for the male to feed so that she can start the second.

The Bewick’s wren (Thryomanes bewickii) is more distinctive in appearance, with its long, sideways-flitting tail edged in white spots, its light colored breast, long white eyebrow, and larger size (up to 5 inches). A year-round resident, it is most commonly found in western Washington but has been noted regularly throughout the state.

The Bewick’s (pronounced like “Buick’s”) wren was named by John James Audubon to commemorate his friend Thomas Bewick, an English naturalist and wood engraver. Although all wrens are prolific and loud songsters, the Bewick’s wren has one of the most beautiful voices. It begins high and rapid, changing to a lower register, ending in trills.

These wrens also readily uses nestboxes, taking as much as ten days to build very sturdy nests. Like most wren species, egg incubation lasts about two weeks, and nestling care before fledging lasts about another two weeks.

These six weeks or so of high-energy wren courting, nesting, and rearing can be among the most fascinating for backyard birders, especially those who make and place nestboxes suited for them. Follow the directions in the Backyard Wildlife Sanctuary packet’s “Nest Boxes For Birds” pamphlet for building the right size house for wrens.

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