Bewick’s Wren
The Bewick’s Wren (Thryomanes bewickii) is one of the many jaunty songbird species found in the family of birds known as Troglodytidae – 85 species in total. Wrens are generally seldom shy, energetic in their movements, and distinguished by short tails often cocked over their backs. The Bewick’s Wren is no exception.
Its range extends from southwest Missouri and southeast Kansas, through Oklahoma, Texas, New Mexico, Arizona, the southern edge of Colorado, and all but the northernmost part of Utah. It can also be found along the Pacific Coast, from the Baja Penninsula into all but the southeast part of California, extending east into the western edge of Nevada, then north along the western edge of Oregon and into the western two-thirds of Washington State.
The Bewick’s Wren was first introduced into the field of ornithology by John James Audubon in 1821, who named it for his friend Thomas Bewick, a British engraver. At that time, the species could be found throughout the Midwest and into the Appalachians. Now it rarely is found east of the Mississippi.
What it looks like
The Bewick’s Wren is a small, active, noisy bird found mostly in scrubby vegetation or open woodlands, but it also can be found near outbuildings of farms within its range. Its upperparts are brown to grayish-brown, with whitish throat and underparts. It has a conspicuous white line over its eye, and shows barring in the middle tail feathers and white spots on the edge of its tail. Both sexes are similar.
Breeding Behavior
Bewick’s Wrens are normally monogamous. During nest building, the pair will forage together. This courtship behavior may prevent them from breeding with other birds. Some pair bonds might extend into a second year; otherwise pair bonds are established in February or March, with nest building starting soon after. They are opportunistic cavity nesters, using a variety of sites such as nest boxes, old woodpecker nests, and even nooks or crevices in old buildings.
Both sexes build the nest – usually a cup nest within the cavity, but occasionally a dome is built over the cup. The female lays 3 to 8 eggs, followed by a 14- to 16-day incubation period. The young fledge the nest after another 14- to 16-days. Both parents feed the young, both in the nest and for another 2 weeks until the young are on their own.
Similar species
Carolina Wren
The Carolina Wren is larger with cinnamon colored underparts and lacks the white tail spots. There is some range overlap, particularly the eastern half of Texas, Oklahoma, and Kansas. However, most of their ranges do not overlap. The Carolina Wren is mostly an eastern bird, with its range extending throughout the southwest and lower Midwest states, the mid-Atlantic, Pennsylvania, the southern tier of New York, and the southern half of Massachusetts.
House Wren
The House Wren is smaller and appears uniformly brownish gray. It lacks the conspicuous eye line, and there is little contrast between its back and underparts. It breeds across most of the lower 48 states, with the exception of the most southern parts. During the winter, it migrates to the southernmost states, into Mexico and Central America.
Conservation status
Although the House Wren doesn’t have a strong resemblance to the Bewick’s Wren, the two species have a different type of relationship. The House Wren’s tendency to destroy nests of other species might be the reason Bewick’s Wrens range and numbers have declined over the last 200 years. During this time, House Wrens expanded west by taking advantage of human activity, including old agriculture fields and increased availability of nest boxes. As House Wren populations grew, they continued to outcompete Bewick’s Wrens for nesting sites, reducing the range of the Bewick’s Wren. Some are now advocating conservation methods ranging from reducing the number of nest boxes to outright destroying House Wrens as a way to try to restore the Bewick’s Wren populations in eastern states.
That’s it for this week. Next week I’ll talk about the Pine Grosbeak.
If you missed last week, click here to read about the Double-crested Cormorant.