By Lee Franks
“No bird more deserves the protection of man than Bewick’s Wren. He does not need man’s encouragement, for he comes of his own accord and instills himself as a member of the community, wherever it suits his taste. He is found about the cowshed and barn along with the Pewee and Barn Swallow; he investigates the pig-sty; then explores the garden fence; and finally mounts to the roof and pours forth one of the sweetest songs that ever was heard.”—Robert Ridgeway 1889; 92-93.
The first recognized Bewick’s Wren (Thryomanes bewickii) collected by J.J. Audubon on its wintering ground in Louisiana in 1821, was described by Audubon and named for his friend, Thomas Bewick, a British engraver. A century ago, Bewick’s Wren was beloved as the “house wren“ of the Appalachians and the Midwest. Today, the species has all but disappeared east of the Mississippi River and has declined in western parts of its range, including California,
The Bewick’s is the most common wren in the Bay Area, especially in shrubby areas, and it prefers the undergrowth areas of Edgewood. These year-round singers are always more abundant than they seem to be, and they frequently nest in the boxes installed throughout the wooded areas of the Park. The mission in this wren’s life appears to involve the investigation of all suspicious noises, which makes it an easy bird to attract.
Recognized by its white eyebrow and breast and long, white-spotted tail (which it wags from side to side). Their upperparts are brown to grayish brown; throat and underparts are whitish. They have a slender down curved bill.
When foraging, this bird uses short, quick hops between perches. It’s highly active, usually pausing only 1-2 seconds at a time. Its main food is arthropod larve and adults (beetles, wasps, caterpillars, butterflies, moths, flies), which it gleans from leaves, branches and trunks of lower strata of weeds, brush, and trees.
It also probes at crevices in branches and trunks, and flips and probes (but does not scratch) dead leaves on the ground. Generally forages solitarily.
Their flights are generally short, 1-2 meters; but longer when chasing intruders or commuting to and from feeding nestlings. In scolding intruders near nests, darts from branch to branch. Adults roost individually at sunset in unmodified depressions, niches and cavities in trees, posts and nest boxes. Young birds roost together for about one month.
Bewick’s use territories for courtship, mating, nesting, and feeding. Territory size and shape vary with distribution of vegetation and with the number of birds. They defend territories by countersinging, chases, and sometimes fights.
The territorial song of this wren resembles that of the song sparrow and generally consists of three distinct parts; a high, quick opening of 2 notes, then lower notes, and ending with a high trill. Listen to some sounds here.
Individual repertoires range from 9 to 22 song types. They often will repeat each song 20-50 times before singing another song. Only the male sings. During the breeding season, the male sings from many high perches in all parts of his territory. Autumn songs are given while foraging on or near the ground. Both sexes use call notes for contact purposes while foraging.
The male initiates nest building, usually in March, but both sexes participate in building. The Bewick’s wren is a cavity nester, so they make use of the nest boxes in the wooded areas of the Park. It takes about 7 days to complete a nest.
The first egg is usually laid between the first and third morning after nest completion. Their clutch size is 5-6, which get incubated over a period of 14-16 days. The female does the brooding, but both parents feed the brood.
Nestlings depart their nest 14-16 days after hatching. These young birds remain together and are fed by their parents for about 2 weeks after fledging. At about 5 weeks of age the young disperse.
The Birds of North America No 315, 1997; E. Dale Kennedy and Douglas W. White.
Birds of San Francisco and the Bay Area; Chris C, Fisher and Joseph Morlan.
Ornithology of Illinois, Robert Ridgeway, 1889