Western Wood-Pewee Contopus sordidulus This information was scanned from The Birds of British Columbia (Campbell et al.), Volume III, pages 26-31. Volumes I, II and III of The Birds of British Columbia can be ordered electronically at: orders@ubcpress.ubc.ca from UBC Press in Vancouver, British Columbia.

 

Range Breeds from central Alaska and southern Yukon east to south-central Manitoba, North Dakota, and Kansas, south to Baja California, Guatemala, and Honduras. Winters from southern Central America to Peru and Bolivia.

Status On the coast, an uncommon to fairly common migrant and summer visitant to the Georgia Depression Ecoprovince, becoming rare to uncommon elsewhere on the coast, including Western Vancouver Island. Absent from the Queen Charlotte Islands. In the interior, an uncommon to fairly common (locally common) migrant and summer visitant throughout the southern and central regions of the province north to the Boreal Plains Ecoprovince; further north and west it becomes uncommon. Breeds.

Status Change No change.

Nonbreeding The Western Wood-Pewee is widely distributed in forested areas throughout much of the southern two-thirds of the province. It is sparsely distributed in the Northern Boreal Mountains and Taiga Plains ecoprovinces. There are also large areas on the coast where the species has not been reported, including much of the exposed coastal areas of Western Vancouver Island, most of the southern and northern regions of the Coast and Mountains Ecoprovince between Rivers Inlet and Prince Rupert, and all of the Queen Charlotte Islands. In the interior, there is a large area on both sides of the Rocky Mountain Trench from Mackenzie north to Lower Post where records of the species are lacking. The Western Wood-Pewee occurs from near sea level to about 1,900 m elevation. It frequents a wide variety of open coniferous, deciduous, and mixed forests, usually near water or around the edges of clearings. Habitats include cottonwood riparian lowlands, beaver meadows, open coniferous forests, aspen and birch parklands, Carry oak woodlands, burns, brushy meadows, swamps, orchards, farmsteads, and gardens. Rand (1944) found the Western Wood-Pewee common at Muncho Lake in the scattered spruces of old alluvial fans. In the Peace River area, Cowan (1939) found it abundant in mature aspen forests. In the Okanagan valley, it is most common in ponderosa pine forests, orchards, gardens, and deciduous stands around lakes below 1,000 m (Cannings et al. 1987). In Mount Revelstoke and Glacier national parks, Van Tighem and Gyug (1983) report the highest densities in mixed forests and wetlands in the Interior Cedar-Hemlock forest. In the Smithers area, Polar (1993) found the highest densities for this species in mature aspen stands, although it also occurred in old and mixed seral stages. Favourite perches for hunting and calling are the dead lower branches of aspens or the tops of smaller trees (Verbeek 1975). In the Coast and Mountains (Western Vancouver Island), Georgia Depression, Southern Interior, and Southern Interior Mountains ecoprovinces, early spring migrants may arrive in the third or fourth week of April, with a peak movement occurring about the second or third week of May. By early May, migrants have reached the Central Interior and Sub-Boreal Interior ecoprovinces, reaching the Boreal Plains by the second week of May; the main movement peaks in those areas by about the third week of that month. Further north, birds arrive about the last 2 weeks of May. In the north, the autumn migration begins shortly after the young are on the wing, and most birds have left by early September. In the south, both on the coast and in the interior, the main movement peaks in late August and early September. By mid-September most birds have left the province, and all birds have gone by the second week of October. Migrants are occasionally grounded by poor weather. In late May 1991,50 Western Wood-Pewees were reported from the Nelson and Castlegar area, including a single flock of 25 birds. On the coast, the Western Wood-Pewee has been reliably recorded in the province from 22 April to 3 October; in the interior, it has been recorded from 23 April to 30 September.

Breeding Nests Eggs Nest Success The Western Wood-Pewee has a widespread breeding distribution from southeastern Vancouver Island east across the province to the west Kootenay and north through the Central Interior to the Skeena River valley in the west and the Peace River area of the Boreal Plains in the east. Breeding records are lacking from Western Vancouver Island, most of the east Kootenay region, all but the extreme southern portions of the Sub-Boreal Interior, and the Northern Boreal Mountains and Taiga Plains. However, the species probably breeds throughout its summer range in the province. The highest numbers for the Western Wood-Pewee in summer occur in the southern portions of the Sub-Boreal Interior (Rising and Schueler 1980). An analysis of Breeding Bird Surveys for the period 1968 through 1993 shows that the number of birds on interior routes has decreased at an average annual rate of 1%; analysis of coastal routes for the same period could not detect a net change in numbers. As early as the mid-1940s, however, Pearse (1946) noted that the Western Wood-Pewee was "seldom heard now" in the vicinity of Comox on Vancouver Island. The Western Wood-Pewee has been recorded breeding from near sea level to 1,700 m elevation. It breeds in forested habitats (45%; n = 170) and human-altered habitats (39%) such as gardens, farms, orchards, parks, playgrounds, campgrounds, and transmission-line corridors. The majority of nests were reported from the Southern Interior, where there was frequent use of gardens close to water. Similar sites were also used in the Georgia Depression and Southern Interior Mountains, where about one-third of all nests were found in altered habitats. These data may be biased towards nests that are more easily found in sparse growth and semi-open, agricultural areas rather than nests that are in forests or woodlands. In the north, this species frequently nests near beaver ponds. Occasionally mixed woods are used for nesting. Most nests (43%; n=142) were reported from cultivated environments. The remaining nests were associated with 24 other classes of open habitat, including swamps, marshes, beaver ponds with drowned trees, small lakes, rangeland, sagebrush, and talus. Cannings et al. (1987) state that breeding wood-pewees in the Okanagan were most abundant in aspen groves around ponds and lakes, often preferring areas with water-killed trees. In Kootenay National Park, breeding habitat is restricted to open Douglas-fir bottomlands along the Kootenay River and mixed successional forests of spruce, aspen, and alder (Poll and Porter 1984). On the coast, the Western Wood-Pewee has been recorded breeding from 25 May to 14 August; in the interior, it has been recorded from 20 May to 17 August.

Nests:  All nests (n = 198) were found in trees, usually living but occasionally dead. Most nests (75%) were found in deciduous trees; trembling aspen (17%), poplar (15%), and black cottonwood (7%) were the most frequently reported native species. A wide variety of garden and orchard species were also used. In the Boreal Plains and Central Interior, up to 50% of the nests were found in trembling aspen, while in the Southern Interior ponderosa pine and poplar were reported with equal frequency (19%; n = 120), followed by trembling aspen (13%). Almost all nests (97%; n = 172 ) were situated on horizontal tree branches, usually well out from the trunk; 25% were in natural forks or saddled the limb . The heights of 187 nest s ranged from 0.4 to 18 m above the ground (or water), with 65% between 2.4 and 8.0 m. Nests were elegantly constructed cups composed mainly of grasses (75%). Other nest materials included lichens (26%), animal hair (15%), feathers (9%), bark strips (6%), and leaves (2%). In addition, mosses and plant down were used, and cobwebs were often incorporated into the outer surface of the basic structure. Lining material consisted of grasses, plant fibres and down, mosses, bark strips, and lichens. Eggs: Dates for 136 clutches ranged from 20 May to 5 August, with 50% recorded between 20 June and 8 July. Calculated dates indicate that eggs could be found as earl y as 17 May. Sizes of 90 clutches ranged from 1 to 5 eggs (1E-1,2E-l9, 3E-45,4 E-24,5 E-1), with 77% having 3 or 4 eggs. The incubation period is 12 or 13 days (Ehrlich et al. 198 8). Nest Success: Of 21 nests found with eggs and followed to a known fate, 10 produced at least 1 fledgling. Young: Dates for 94 broods ranged from 20 June to 17 August, with 52% recorded between 8 and 22 July. Calculate d date s indicate that young could be found as earl y as 29 May . Sizes of 59 broods ranged from 1 to 5 young (1Y-8, 2Y1 0, 3Y-27, 4Y-13, 5Y-1), with 68% having 3 or 4 young. The nestling period is 14 to 18 days (Ehrlich et al. 1988). Brown-headed Cowbird Parasitism: In British Columbia, 6% of 139 nests found with eggs or young were parasitized by the cowbird. Interior nest parasitism was 5% (n = 133); only 1 of 6 coastal nests was parasitized. Friedmann and Kiff (1985) list only 8 instances of the Western Wood-Pewee serving as host for the cowbird in North America; 1 was from British Columbia (Friedmann 1934).

Remarks Two subspecies occur in Canada: C. s. velici Coues and C. s. saturatus Bishop, the latter being the race found in British Columbia (American Ornithologists' Union 1957). All records of this species in British Columbia earlier than 22 April (see Cannings et al. 1987) and later than 3 October have been excluded from the analysis because they lack convincing details. A Western Wood-Pewee banded as a fledgling in Vernon in May 1934 returned in May 1935 and "nested not only in the same apple tree but on top of its old nests (Fowle 1940). Bent (1942) provides additional life-history information.