Range Resident from southwestern British Columbia, including southern Vancouver Island, south along the coastal slope to southern California and Baja California. Also breeds across the middle of the continent from southern Wyoming and eastern Nebraska to Michigan, southern Ontario, and southeastern New York south to central Texas, northern Arkansas, Georgia, South Carolina, and the northern portion of the Gulf states. Winters throughout most of its breeding range. Resident in parts of the Mexican highlands.

Status On the coast, a fairly common resident in the Georgia Depression Ecoprovince; uncommon resident at lower elevations in the southern portions of the Coast and Mountains Ecoprovince; very rare on Western Vancouver Island in the Coast and Mountains. Breeds.

Status Change No change.

Nonbreeding In British Columbia, the Bewick's Wren occurs almost exclusively in the Georgia Depression, where 99% of all observations have been recorded. It has not been reported from the coast north of Cortes Island. There are only 2 records from the interior, both from Manning Park. On Vancouver Island, the Bewick's Wren occurs regularly from Sooke and Victoria along the east coast, north to Campbell River and Cortes Island. It occurs less regularly west to Port Renfrew, Bamfield, Port Alberni, and Long Beach. On the mainland, it occurs regularly in the lower Fraser River valley from the coast east to Cultus and Harrison lakes. The easternmost records are from the western slope of Manning Park, and the northernmost are from the Sechelt Peninsula, Pemberton, and Emory Creek. The highest numbers in winter occur in the Georgia Depression, specifically near Victoria and on the Fraser River delta from Ladner to White Rock The Bewick's Wren is a bird of low elevations that occurs mainly between sea level and 100 m. About 90% of all records for this wren in the nonbreeding season are within 100 m of sea level. Where roads and subdivisions have created suitable habitat, it can reach higher elevations. There is 1 record from 1,500 m in Garibaldi Park. The Bewick's Wren is a bird of edge habitats where coniferous forest gives way to a tangled understorey of shrubs, trailing blackberry, salal, western flowering dogwood, cascara, willow, pink spirea, thickets of Nootka rose, and Himalayan blackberry; and of brush areas along the borders of fields, powerline cuts, around swampy ponds or sloughs, river and creek banks, lakeshores, and road edges. It is also a common visitor to brushy parks, residential gardens, and bird feeders. During nonbreeding seasons it is mainly a solitary bird, except for resident pairs, which often occur together. Like most secretive, ground-dwelling birds, the Bewick's Wren is more noticeable during the spring, when males are singing. There is no evidence that this wren is migratory in British Columbia. It winters throughout its range on the Fraser River delta, along the Sunshine Coast, and on southeastern Vancouver Island, the Gulf Islands, and the extreme southern end of the south Coast and Mountains near Harrison Lake. On the coast, the Bewick's Wren has been recorded throughout the year.

Breeding Nests Eggs Nest Success The Bewick's Wren breeds throughout its primary range on southeastern Vancouver Island, north to Campbell River and Cortes Island, on the Gulf Islands, and on the Fraser Lowland east to Chilliwack. It probably also breeds in the Fraser Lowland east to Hope, and possibly north to Emory Creek, Squamish, and the Sechelt Peninsula. The highest numbers in summer occur in the Georgia Depression. An analysis of Breeding Bird Surveys for the period 1968 through 1993 could not detect a net change in numbers on coastal routes. Nesting occurs mainly below 100 m elevation. The highest elevation reported for breeding is 225 m. The Bewick's Wren is one species of songbird that can survive and breed in habitat that has been heavily altered by humans. Primary breeding habitat includes brushy, open woodlands in suburban and rural areas, or farmlands along the edges of forested areas (90%; n = 99). Nearly 80% of nests (n = 92) were described as occurring in backyards, on farms, or in gardens. Although the Bewick's Wren remains near the ground most of the time, territorial males may perch at the top of trees as tall as 20 m when singing. The Bewick's Wren has been recorded breeding in British Columbia between 17 March and 5 August.

Nests:  Most nests were found in buildings (47%; n = 135), including sheds, garages, barns, and living or dead trees (40%), including Douglas-fir, Carry oak, western redcedar, various birches, red alder, and black cottonwood. Posts and poles (5%), abandoned automobiles (4%), banks, and shrubs were also used. It nested successfully in greenhouses, garages, or sheds that were actively used by humans, which suggests a relatively high tolerance for disturbance. The Bewick's Wren requires cavities such as abandoned woodpecker nests, natural cavities in trees, or nest boxes for nesting. In suburban and rural areas it often uses cavities created by cracks in buildings or openings in abandoned machinery and junk pile. Specific sites included artificial cavities, containers, or nest boxes (42%; n = 157), natural cavities or crevices (34%), and rafters or other supports in buildings (15%). Some of the more unusual nest sites chosen by this adaptable wren included an enclosed space in a brush pile, the roots of upturned tree stumps, pockets or sleeves of clothing left hanging in abandoned buildings, saddlery and other bits of harness, garage drawers and cupboards left slightly ajar, behind a frying pan hanging on a post, mailboxes, a box of wood scraps under a sundeck, empty flowerpots, old Barn Swallow nests, and a paper bag half filled with nails. The heights for 118 nests ranged from 0.3 to 6.0 m, with 68% between 0.9 and 1.8 m. In 126 Bewick's Wren nests, the 6 most frequently used materials were twigs (74%), grasses (49%), feathers (38%), moss (32%), leaves (28%), and hair (27%). Eggs: Dates for 102 clutches ranged from 17 March to 15 July, with 51% recorded between 9 April and 30 May. Clutch size ranged from 1 to 7 eggs (1E-7, 2E-4, 3E-4, 4E-19, 5E-38, 6E-26, 7E-4), with 63% having 5 or 6 eggs. The incubation period in British Columbia is 15 to 16 days (n = 3). In California, the incubation period is reported as 14 days (Miller 1941). Nest Success: Of 36 nests found with eggs and followed to a known fate, 24 produced at least 1 fledgling, for a success rate of 67%. Young: Dates for 66 broods ranged from 5 April to 5 August, with 53% recorded between 28 April and 15 June. Brood size ranged from 1 to 7 young (1Y-2, 2Y-5, 3Y-7, 4Y-23, 5Y-21, 6Y-7, 7Y-1), with 67% having 4 or 5 young. The nestling period in British Columbia is 18 to 22 days (n = 5). Miller (1941) gives the nestling period in California as 14 days. In British Columbia, the Bewick's Wren is often double-brooded and may use the same nest for successive broods (Pearse 1957). Brown-headed Cowbird Parasitism: In 147 nests recorded with eggs or young in British Columbia, 2 were parasitized by the cowbird. In 1 nest, the adults reared a young cowbird to the fledging stage, but not their own young (Lemon 1969). Friedmann (1963,1971) and Friedmann et al. (1977) note only 12 records of parasitism by cowbirds, but suggest that the Bewick's Wren may be more frequently parasitized than is known.

Remarks The subspecies of Bewick's Wren that occurs in British Columbia is T. b. calophonus (American Ornithologists' Union 1957). This subspecies ranges from southwestern British Columbia south through western Washington and western Oregon. The Bewick's Wren has been blue-listed in the eastern and central United States since 1972 (Ehtlich et al. 1988), principally because of declines in the Appalachian, Southern Atlantic Coast, and Central Southern regions. Breeding Bird Surveys show significant declines there for the period 1968 through 1979 (Robbins et al. 1986); those trends, however, did not appear in the west. Declines have been attributed to loss of woodlots and outbuildings and the use of agricultural pesticides on modern farms (Ehrlich et al. 1988). As well, the problem for wrens and many other small insectivorous birds probably lies in the poorly controlled use of domestic pesticides, combined with an increased abundance of feral and domestic cats.