Olive-sided Flycatcher Contopus cooperi Scientific name definitions

With its loud and resounding song— quick, THREE BEERS! —and its position of prominence perched atop a large tree or snag, the Olive-sided Flycatcher is one of the most recognizable inhabitants of North America's coniferous forest, breeding from sea level to 3,350 m in the Rocky Mountains. This flycatcher undergoes one of the longest and most protracted migrations of all Nearctic migrants, wintering primarily in Panama and the Andes Mountains of South America.

It breeds in habitat along forest edges and openings, including burns; natural edges of bogs, marshes, and open water; semiopen forest; and harvested forest with some structure retained. Tall, prominent trees and snags, which serve as singing and foraging perches, and unobstructed air space for foraging, are common features of all nesting habitats.

One of the most tyrannical species of the tyrant flycatchers, both members of the pair aggressively defend their nest areas. Nesting territories are relatively large for a passerine bird; 1 pair may defend up to 40–45 ha. The Olive-sided Flycatcher is monogamous and produces 3–4 eggs per clutch and 1 clutch per pair per year. Nests are open-cup structures placed at various heights above ground and well out from the trunk of a coniferous tree in a cluster of needles and twigs on a horizontal branch.

Olive-sided Flycatchers prey almost exclusively on flying insects, especially bees. They often forage from high, prominent perches at the tops of snags or dead tips or uppermost branches of live trees, from which they fly out (sallying) to snatch flying insects, and then return to the same or another prominent perch (Yo-Yo flight). This typical behavior prompted Marshall (Marshall 1988b Marshall, J. T. (1988). Birds lost from a Giant Sequoia forest during fifty years. Condor 90(2):359–372. Close ) to describe this species as “the Peregrine of flycatchers.”

In the past 30 years this species has experienced significant declines in populations throughout its range, causing it to be listed as a Sensitive Species or Species of Concern by several federal and state agencies and conservation groups. Until recently, most life-history information on Olive-sided Flycatchers was anecdotal. Recent species-specific research on habitat relationships and nesting ecology in Alaska (Wright 1997a Wright, J. M. (1997a). Olive-sided Flycatchers in central Alaska, 1994-1996. Juneau, AK: Alaska Dept. Fish and Game. Fed. Aid in Wildl. Restoration. Close ), Colorado (Kotliar and Melcher Kotliar and Melcher 1997 Kotliar, N. B. and C. P. Melcher. (1997). Habitat selection and nesting success of Olive-sided Flycatchers under natural and managed disturbance regimes. Fort Collins, CO: U.S. Fish and Wildl. Serv., U.S. Geol. Surv.-Biol. Resour. Div. Close , Kotliar and Melcher 1998 Kotliar, N. B. and C. P. Melcher. (1998). Habitat selection and behavior of Olive-sided Flycatchers under natural and managed disturbance regimes. Fort Collins, CO: U.S. Fish and Wildl. Serv., U.S. Geol. Surv.-Biol. Resour. Div. Close ), and Oregon (Altman Altman 1998 Altman, B. (1998). Productivity of the Olive-sided Flycatcher in the Cascade Mountains of northern Oregon: a pilot project to assess nesting success as a potential factor in population declines. Oregon State Office, Portland: Unpubl. report submitted to U.S. Fish and Wildl. Serv. Close , Altman 1999b Altman, B. (1999b). Nest success and habitat relationships of the Olive-sided Flycatcher in managed forests of northwestern Oregon. Oregon State Office, Portland: Unpubl. report submitted to U.S. Fish and Wildl. Serv. Close ) has advanced our knowledge of the species substantially.