Olive-sided Flycatcher Contopus cooperi This information was scanned from The Birds of British Columbia (Campbell et al.), Volume III, pages 20-24. 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 western and central Alaska east across north-central Canada to central Newfoundland, and south to northern Baja California in the west; in the east from central Saskatchewan, Manitoba, and the northern Great Lakes states south through New York in mountainous areas to eastern Tennessee and western North Carolina. Winters in South America from Colombia and Venezuela to Peru, and casually in southern California.

Status Uncommon migrant and summer visitant throughout most of the province; absent from the Queen Charlotte Islands.

Status Change No change.

Nonbreeding The Olive-sided Flycatcher is widely distributed throughout British Columbia. It occurs from Vancouver Island and the mainland coast east across the province to the Rocky Mountains, and in suitable habitat throughout the interior to the extreme northern portions of the province. It is absent from the Queen Charlotte Islands. The Olive-sided Flycatcher has been reported from near sea level to the subalpine and alpine regions near 2,400 m elevation. It prefers the edges of mature coniferous forests, both pure and mixed, especially adjacent to water. These edges may be natural (ponds, sloughs, lakes, wetlands, estuaries, Slowdowns, and rivers) or human-made (burns, clearcuts, transmission-line corridors, highways, and recreational clearings such as ski areas and campsites). It also frequents open woodlands on steep mountain slopes (Munro 1935a ; Van Tighemand Gyug 1983) and deciduous woodlands, especially in swamp and flood plain forests. Within these habitats, tall trees with dead tops are necessary perch sites for maintenance, singing, and foraging activities. Erskine (1977) mentions that as long as nags and stubs remain, the Olive-sided Flycatcher will be a characteristic bird of burned and clearcut reg ions in boreal Canada . This species shows flexibility in its choice of habitats. It has been found in old-growth and climax forests near Sproat Lake (Bryant et al.1993) and Terrace (Webster 1969a), and in immature and young second-growth forests near Port McNeill, Port Alice (Buckner et al.1975), and Garibaldi Park. On the Sunshine Coast, the Olive-sided Flycatcher occurs on the Tetrahedron Plat eau in climax mountain hem lock and yellow cedar forests, but only where there are opening s created by upland bog s with standing snags (T. Greenfield pers. comm.). On the south coast, spring migration begins as early as the third week of April, while on the north coast the earliest spring migrants arrive in early May. The main coastal movement occurs from mid to late May. In the southern portions of the interior, spring arrivals also begin to appear about the third week of April but the main movement is not evident until mid to late May . By early May, spring migrants have reached the Central Interior and Boreal Plains ecoprovinces, and by mid-May have reached the far northern portions of the province. In autumn, the migration is less pronounced. Most birds have left the far northern interior regions of the province by the end of August. In the southern portions of the interior and along the coast, a few birds can be found through September. By October, all birds have left the province. On the coast, the Olive-sided Flycatcher has been recorded from 20 April to 29 September; in the interior, it has been recorded from 20 April to 27 September.

Breeding Nests Eggs Nest Success The Olive-sided Flycatcher has a widespread breeding distribution across the southern portions of the province, including Vancouver Island, although it likely breeds throughout most of forested British Columbia except the Queen Charlotte Islands. Its highest numbers occur mainly on southeastern Vancouver Island, in the Georgia Depression Ecoprovince, and in the southwestern portion of the Sub-Boreal Interior Ecoprovince. It appears to be sparsely but evenly distributed elsewhere in suitable habitats. An analysis of Breeding Bird Surveys for the period 1968 through 1993 shows that the mean number of birds on coastal routes decreased at an average annual rate of 5%; the mean number of birds on interior routes also decreased at an average annual rate of 5% over the same period. Summaries of North American Breeding Bird Surveys indicate that between 1965 and 1985 western continental populations of the Olive-sided Flycatcher declined sharply, with British Columbia populations showing the strongest decrease (Robbins et al. 1986; Droege and Sauer 1987). Possible reasons for the decline include destruction of tropical wintering habitats, loss of suitable breeding and foraging habitats (e.g., suitable perch sites in tall mature trees), logging activities that alter age classes of forests, and use of forest pesticides and herbicides (Marshall 1988). The Olive-sided Flycatcher breeds from near sea level to about 2,200 m elevation. On the south coast, it was 10 times more abundant at 1,100 m than between 100 and 400 m elevation (Weber 1975). In the interior, it is a scarce breeder in valley bottoms but becomes more abundant at higher elevations. In the Okanagan valley, most breeding records were from above 900 m elevation, within the Douglas-fir zone; however, there are records from lower elevations at Richter Lake (600 m) and Okanagan Landing (Cannings et al. 1987). Breeding habitat includes the edges of semi-open mature coniferous forests and mixed woodlands, usually near water. One nest was found in a shrub thicket and 3 nests were in human-influenced habitats. Considering the widespread disturbance of habitats in this province (from logging, agriculture, urbanization, and transportation corridors), it is significant that 79% of the nests (n = 19) were found in pristine forests. Half of the Olive-sided Flycatcher nests were found in semi-open coniferous forests. Most of the rest were in mixed forests. On the coast, the Olive-sided Flycatcher has been recorded breeding from 30 May to 5 August; in the interior, it has been recorded from 20 May (calculated) to 19 August (Wade 1977).

Nests:  Most nests (76%; n = 25) were situated in coniferous trees, including Douglas-fir (45%), ponderosa pine, white spruce, and Engelmann spruce. Several nests were found in trembling aspen and 1 was found in a willow shrub. All of the described nests (n = 17) were attached to the upper surface of a horizontal branch, generally well out on the branch but occasionally near the trunk. Nests were bulky structures of interwoven twigs, sticks, and rootlets. The nest cup was lined with beard-lichens, grass, and other plant fibres. Nest heights (n = 27) ranged from 3 to 15 m; 14 were between 6 and 12 m. Eggs: Dates for 14 clutches ranged from 22 May to 15 July. Calculated dates indicate that nests may have eggs as early as 20 May. Sizes of 8 clutches ranged from 1 to 4 eggs (1E-1, 2E-1, 3E-3, 4E-3). Bent (1942) states that the Olive-sided Flycatcher almost invariably lays 3 eggs, occasionally 4. Bendire (1895) states that about 1 nest in 20 contains 4 eggs. The incubation period is between 10 and 17 days (Walkinshaw 1957); Ehrlich et al. (1988) give it as 14 days. Nest Success: Of 5 nests found with eggs and followed to a known fate, 2 produced at least 1 fledgling. Young: Dates for 20 broods ranged from 3 June to 19 August. Sizes of 14 broods ranged from 1 to 4 young (1Y-1,2Y-2, 3Y-9, 4Y-2). The nestling period is 21 to 23 days (Ehrlich et al. 1988). Brown-headed Cowbird Parasitism: In British Columbia, only 1 of 26 nests recorded with eggs or young was parasitized by the cowbird. That nest was discovered on southern Vancouver Island. It was only the fourth reported instance in North America of the Olive-sided Flycatcher acting as host for the cowbird (Friedmann 1963; Friedmann et al. 1977; Friedmann and Kiff 1985).

Remarks There are no recognized subspecies of the Olivesided Flycatcher. Bent (1942) gives general life-history information for this species.