Pacific Wren Life History

Habitat

Habitat ForestsThe Pacific Wren lives in forested habitats from sea level to 12,000 feet in the western United States and Canada. They are most common in old-growth evergreen forests, but they also live in deciduous forests, mixed evergreen and deciduous forests, and aspen stands. Within these habitats they often live near water and in areas with fallen logs, dead trees and stumps, brush piles, and thick understory cover of mosses and ferns. During the nonbreeding season, some individuals move to lower elevations and use many habitats including scrub oak, pinyon-juniper forests, and sometimes parks and gardens. Back to top

Food

Food InsectsPacific Wrens are insectivores; they eat insects such as beetles, caterpillars, ants, as well as spiders, mites, ticks, millipedes, flies, and bees. They hop slowly on the ground or just above the ground inspecting crevices, decaying wood, upturned roots, and vegetation for food. They capture prey by picking it off surfaces or by probing in decaying bark. During the nonbreeding season, Pacific Wrens sometimes eat juniper berries. Back to top

Nesting

Nest Placement

Nest CavityPacific Wrens build domed-shaped globular nests and also nest inside natural cavities. Males build nests often near streams in roots of upturned trees, under creek banks, in decaying logs, in hanging moss, or in dead trees. Females help line the inside of the nest, but do not build them. Nest height ranges from ground level to 23 feet above the ground.

Nest Description

Males build nests out of moss, bark, twigs, rootlets, grass, and other plant material they find close to the nest site to help with camouflage. Males and females line the nest with feathers and animal hair. Nest size varies depending on the size of the cavity and placement of the nest. At times, nests can be the size of a football.

Nesting Facts
Clutch Size:1-9 eggs
Number of Broods:1-2 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:14-17 days
Nestling Period:15-17 days
Egg Description:White eggs with small pale to reddish brown spots concentrated on the larger end of the egg.
Condition at Hatching:Nestlings are naked with only a few straggly down feathers.
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Behavior

Behavior Ground ForagerPacific Wrens fly short distances with rapid wingbeats in the understory. Their movements are rather mouselike as they scurry and hop along fallen trees and roots. They can also cling to the tree trunks similar to a Brown Creeper. Pacific Wrens are energetic birds that often bob their heads or bodies even when they are standing still. During the breeding season males vigorously sing from prominent perches in the understory. When a female enters a male’s territory, he continues to sing, flutters his wings, and cocks his tail side to side. During courtship, the male leads the female around to each of several nests he has built in his territory. The female then chooses which nest to use. Pacific Wrens maintain territories year-round, although territories often shrink during the nonbreeding season. Pacific Wrens do not form flocks with other species and are normally solitary or paired with their mate. Back to top

Conservation

Conservation Low ConcernPacific Wrens are fairly numerous and their populations were stable between 1966 and 2015, according to the North American Breeding Bird Survey. Partners in Flight estimates the global breeding population is 6 million, with 73% spending some part of the year in the U.S., and 41% in Canada. It is not on the 2016 State of North America’s Birds Watch List, and rates a 10 out of 20 on the Continental Concern Score. Although populations appear stable, their old-growth habitat is threatened by logging and management practices that remove downed logs, slash piles, and upturned roots which are important for nesting and foraging. Back to top

Backyard Tips

If you live within their breeding range, you may be able to attract one to your yard by installing a nest box. Be sure to have the nest box ready before the breeding season begins complete with a predator guard. Find plans to build your own nest box at NestWatch.

Landscaping with native plants can also attract Pacific Wrens. Maintaining areas with dense vegetation and brush piles can provide foraging and maybe even nesting opportunities. Learn more about landscaping with native plants at Habitat Network.

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Credits

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

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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