Bewick's Wren Life History

Habitat

Habitat Open WoodlandsBewick’s Wrens favor brushy areas, scrub and thickets in open country, or open woodland. Depending on where you live, you may find them in chaparral-covered hillsides, oak woodlands, mixed evergreen forests, desert scrub, stands of prickly pear and other cacti, mesquite and century plant, willows and tamarisk, hedgerows, or suburban plantings. Bewick’s Wrens normally breed in areas that contain a mixture of thick scrubby vegetation and open woodland.Back to top

Food

Food InsectsBewick’s Wrens eat the eggs, larvae, pupae, and adults of insects and other small invertebrates. Common prey animals include bugs, beetles, bees and wasps, caterpillars, butterflies, moths, grasshoppers, crickets, flies, and spiders. Bewick’s Wrens also occasionally eat seeds, fruit, and other plant matter, especially in winter. Bewick’s Wren nestlings receive mostly caterpillars, spiders, grasshoppers, and insect pupae. Adults sometimes consume pebbles and mud, perhaps for nutrients or to help with the grinding digestion of their food.Back to top

Nesting

Nest Placement

Nest CavityBewick’s Wrens usually build their nests in cavities or on ledges within 30 feet of the ground. Males often begin the process, with the female contributing equally by the end. Common sites include rock crevices and ledges, brush piles, abandoned woodpecker nest cavities, outbuildings, nest boxes, and abandoned automobiles.

Nest Description

The Bewick’s Wren’s cup-shaped nest has a base of sticks, grasses, rootlets, leaves, moss, or other plant materials, depending on what the local environment provides. Many contain spider egg cases. The open cup may be lined with feathers, wool, hair, or plant down, with a final inner lining of snakeskin. The male initiates nest building; both sexes participate. The construction process usually takes less than 8 days, though sometimes it can stall for long periods and require weeks to complete. The nest is about 2.5 to 3 inches high and 4 or 5 inches in diameter, the cup about 1-2 inches deep and 2-2.5 inches in diameter.

Nesting Facts
Clutch Size:3-8 eggs
Number of Broods:1-3 broods
Egg Length:0.6-0.8 in (1.5-1.9 cm)
Egg Width:0.5-0.6 in (1.2-1.4 cm)
Incubation Period:14-16 days
Nestling Period:14-16 days
Egg Description:White with reddish-brown or purplish spots.
Condition at Hatching:Weight about 1.4 grams (1/20 ounce); eyes tightly closed; skin pink, with sparse down.
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Behavior

Behavior Foliage GleanerNimble and acrobatic, Bewick’s Wrens often hang upside down as they glean insects and spiders from trunks, branches, and leaves. They usually forage in the undergrowth less than 10 feet up, or peck at the ground between short hops. Occasionally they’ll catch insects on the wing. Seizing a prey animal in its bill, a Bewick’s Wren crushes it, shakes it, or bashes it against a branch. Having thus subdued its food, the wren swallows it whole. After a meal, this bird like many others may use its twig perch as a napkin, wiping its bill as many as 100 times. When it leaves the cover of vegetation, a Bewick’s Wren typically darts straight for its destination in a quick, level flight. A male’s weapon of choice for year-round territorial defense is his singing voice. Dueling crooners perch within about 20 feet of each other to trade a barrage of competing songs and harsh calls. Males may also give chase to fellow Bewick’s Wrens or House Wrens that impinge on their territory. (The House Wren usually wins.) During courtship, the male may feed the female, or spread his tail and turn from side to side; the female utters hoarse begging calls or a high clear note. The Bewick’s Wren often cocks its long tail and wags it from side to side, sometimes fanning the feathers.Back to top

Conservation

Conservation Low ConcernBewick's Wren populations declined by about 39% between 1966 and 2015, according to the North American Breeding Bird Survey. Partners in Flight estimates the global breeding population at 5.6 million, with 71% spending part of the year in the U.S., 30% in Mexico, and 1% in Canada. The species rates an 11 out of 20 on the Continental Concern Score. Bewick's Wren is not on the 2016 State of North America's Birds' Watch List, but heavy declines in the east, placed the Eastern Bewick’s Wren on the 2014 State of the Birds Watch List, which lists bird species that are at risk of becoming threatened or endangered without conservation action. Once common across the Midwest and eastern mountains, the Bewick’s Wren saw its population begin to plummet in the early twentieth century. The bird has now all but disappeared east of the Mississippi River, and has also declined in western parts of its range. The House Wren is a likely culprit. Drawn to the same nesting sites as Bewick’s, this widespread wren doesn’t hesitate to appropriate the other birds’ real estate, ejecting eggs and destroying nests. Humans may be inadvertently helping House Wrens usurp the Bewick’s Wren by allowing the reforestation of former farm fields, and also by providing nest boxes that get snapped up by House Wrens. Bewick’s Wren populations may also be falling prey to agricultural pesticide use, and to competition with the European Starling, House Sparrow, Carolina Wren, and Song Sparrow.Back to top

Backyard Tips

If you live within the Bewick’s Wren’s range, you might attract this bird to your yard by landscaping with native shrubs such as willow, mesquite, elderberry, and chaparral plants, or by keeping a brush pile in your yard.

This species may visit backyards if food is available. Find out more about what this bird likes to eat by using the Project FeederWatch Common Feeder Birds bird list.

Consider putting up a nest box to attract a breeding pair. Make sure you put it up well before breeding season. Attach a guard to keep predators from raiding eggs and young. Find out more about nest boxes on All About Birdhouses, where you'll find plans for building a nest box of the appropriate size for Bewick's Wren.

Bird-friendly Winter Gardens, Birdsleuth, 2016.

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Credits

Dunne, P. (2006). Pete Dunne's essential field guide companion. Houghton Mifflin Harcourt, New York, USA.

Kennedy, E. Dale and Douglas W. White. 2013. Bewick's Wren (Thryomanes bewickii), version 2.0. In The Birds of North America (P. G. Rodewald, editor). Cornell Lab of Ornithology, Ithaca, New York, USA.

Lutmerding, J. A. and A. S. Love. Longevity records of North American birds. Version 2015.2. Patuxent Wildlife Research Center, Bird Banding Laboratory 2015.

North American Bird Conservation Initiative. 2014. The State of the Birds 2014 Report. US Department of Interior, Washington, DC, USA.

Partners in Flight (2017). Avian Conservation Assessment Database. 2017.

Sauer, J. R., D. K. Niven, J. E. Hines, D. J. Ziolkowski, Jr., K. L. Pardieck, J. E. Fallon, and W. A. Link (2017). The North American Breeding Bird Survey, Results and Analysis 1966–2015. Version 2.07.2017. USGS Patuxent Wildlife Research Center, Laurel, MD, USA.

Sibley, D. A. (2014). The Sibley guide to birds, second edition. Alfred A. Knopf, New York, USA.

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