Olive-sided Flycatcher Habitat Model
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Draft Date:
February, 2001

Olive-sided flycatcher, Contopus cooperi (= C. borealis) . Also known as Tyrannus or Cooper's Flycatcher. (Bent 1942, Altman and Sallabanks 2000)

Use of Study Area Resources:
Reproduction. Olive-sided flycatcher breeding range extends from Newfoundland, west to Alaska, south to California and along the mountain ranges of the West to Arizona. The eastern part of its range extends south into Wisconsin, and Pennsylvania, and along the upper elevations of the Appalachians as far south as Virginia. (DeGraaf and Rudis 1986, National Geographic Society 1987). The entire study area is included within their breeding range, although no nesting has been documented in either eastern Massachusetts or the lowlands of southern New Hampshire in several decades (Peterson and Fichtel 1992). These birds occur on coastal islands in the Northeast. Olive-sided flycatchers winter primarily in the mountains of Central and South America (Peterson and Fichtel 1992).

Habitat Requirements:
Cover. Olive-sided flycatchers frequent coniferous forests, especially with tall standing dead trees. They prefer spruce, fir, balsam, pine, or mixed woodlands near edges and clearings, wooded streams, swamps, bogs, edges of lakes or rivers (Knight 1908, Forbush 1927, Bent 1942, DeGraaf and Rudis 1986, Peterson and Fichtel 1992, DeGraaf and Rappole 1995). 

Bent (1942), working in Plymouth Massachusetts, documented nests in pitch pines with a dense understory that included scrub oak, and that was in the vicinity of several ponds. In eastern Massachusetts, which offers few coniferous forests.  Occasional nesting was documented in orchards, juniper shrubs in abandoned fields, or in open groves (Forbush 1927), presumably for lack of better habitat. Forbush (1927) also noted that olive-sided flycatchers would use "lowlands near the sea, but in such cases it nests near water or wet lands", and Bent (1942) reported them at forest edge on the Pacific Ocean. Altman and Sallabanks (2000) note that the association of olive-sided flycatchers with water may be due to higher insect abundance in these areas, and that association of the birds with water bodies or wetlands "is particularly true in boreal forest in the northern portion of (their) breeding range".  Peterson (1988) noted that most nesting territories included standing dead trees which were used for singing or foraging perches.  Burned or flooded forest may provide nest structure in the form of dead standing trees (Peterson and Fichtel 1992).

Olive-sided flycatchers feed primarily on flying insects, typically sallying forth from standing dead snags to make a capture, and often returning to the same perch (Altman and Sallabanks 2000). Favored prey includes bees, and ants; they also commonly take flies, moths, grasshoppers, dragonflies, and beetles (Forbush 1927, Bent 1942) . Because olive-sided flycatchers locate their prey visually, they require habitats that offer perches with unobstructed air space for foraging. Fitzpatrick (1978 in Altman and Sallabanks 2000) observed that "olive-sided flycatchers typically forage in edge or open-canopy situations where light intensity is at a maximum and prey can be spotted more easily against the solid lighted background of the sky".  Accordingly, perch trees, a prey base, and an open canopy are key components of suitable habitat, for either nesting or wintering.  In Arizona, Idaho and the northern Rocky Mountains, olive-sided flycatchers have been found to be more abundant in partially logged forests, whether group-cut or selectively cut to remove larger trees of marketable size, thus thinning the overstory, than in either unharvested or clear-cut units (Altman and Sallabanks 2000). Watersheds with clearcuts were found to be more often used than unharvested watersheds (Altman and Sallabanks 2000). Presumably, partial-cutting provides both perch trees and the reduced canopy coverage beneficial to olive-sided flycatchers for foraging.

Special Requirements:
"Several acres" (DeGraaf and Rudis 1986) or "at least 20 ha" may be needed to sustain a pair (LeGrand and Hall 1989 in Peterson and Fichtel 1992). Altman and Sallabanks (2000) note that Olive-sided flycatchers are aggressive, and "one pair may defend a territory of 40-45 ha".

Habitat was mapped by selecting appropriate cover types (see following table).  These included palustrine forested wetland, or coniferous and mixed forest either adjoining clearings (shrub or grasslands) or adjoining a coastal or interior water feature (e.g., stream, lake, bay, ocean bluff mapped from USGS hydrology coverages).   Habitat patches then were scored according to size; patches smaller than 2 ha in area were eliminated; larger patches up to 9 ha were scored 0.2; patches larger than 9 and up to 20 ha were scored 0.5; larger patches were scored 1.0.

NWI Designations
(wetlands only)
Cover Types Cover Suitability
(0 - 1 scale)
Upland deciduous forest
Upland coniferous forest 1.0*
Upland mixed forest 1.0*
Grassland **
Upland scrub/shrub **
Bare ground
PEM, L2EM Lake/pond, emergent vegetation
PFOcon Palustrine forest, conifer 1.0
PFOdec Palustrine forest, deciduous
PSSdec Palustrine scrub shrub, deciduous
PSScon Palustrine scrub shrub, conifer **
PAB, L2AB Lake/pond, aquatic vegetation
L1UB, PUB Lake/pond, unconsolidated bottom
L2US Lake, unconsolidated shore
L2RS Lake, rocky shore
R1UB Riverine subtidal unconsolidated
Rper Riverine perennial
E1AB Estuarine subtidal vegetated
E1UB Estuarine subtidal unconsolidated bottom
E2AB Estuarine intertidal algae
E2EM Estuarine intertidal emergent
E2RS, R1RS Estuarine, tidal river rocky shore
E2SS Estuarine intertidal shrub
E2US Estuarine intertidal unconsolidated shore
M1AB Marine subtidal vegetated
M1UB Marine subtidal unconsolidated bottom
M2AB Marine intertidal algae
M2RS Marine intertidal rocky shore
M2US Marine intertidal unconsolidated shore
NOTES *score if the feature adjoins a clearing or a water feature
**types which may constitute a clearing

Model testing: The olive-sided flycatcher occurrences along Breeding Bird Survey routes within the study area were used to test the habitat map. We compared the presence of habitat near a random set of 797 upland points to that for Breeding Bird Survey stops at which olive-sided flycatchers were observed in 1990, or 1997 through 2000. Of the 57 sites with birds, 53 had mapped habitat, while 595 sites out of the 797 randomly distributed sites had habitat. The Chi-square was significant (alpha < 0.0015), indicating that the overall model does indicate localities useful to olive-sided flycatchers.  Tests of progressively higher suitability levels (0.5, 1.0) showed correspondingly higher levels of significance.

Altman, B. and R. Sallabanks. 2000. Olive-sided Flycatcher. In A. Poole and F. Gill, (eds.) The Birds of North America, No. 502. The Academy of Natural Sciences, Philadelphia, and The American Ornithologists' Union, Washington, D.C.

Bent, A.C. 1942. Life Histories of North American Flycatchers, Larks, Swallows and Their Allies. U.S. National Museum, Bulletin 179. p 288-302.

DeGraaf, R.M. and J.H. Rappole. 1995. Neotropical Migratory Birds: Natural History, Distribution and Population Change. Comstock Publishing Associates, Ithaca, NY. 1995. 676 pp.

DeGraaf, R.M. and D.D. Rudis. 1986. New England Wildlife: habitat, natural history, and distribution. Gen. Tech. Rep. NE-108. Broomall, PA: USDA/USFS. 491p.

Forbush, E.H. 1927. Birds of Massachusetts and Other New England States. Commonwealth of Massachusetts, Norwood, MA. p 344-347.

Knight, O.W. 1908. The Birds of Maine. C.H. Glass, Bangor, ME. 693 pp.

National Geographic Society. 1987. Field Guide to the Birds of North America. National Geographic Society, Washington D.C. 464 pp.

Peterson, J.M. 1988. Olive-sided Flycatcher, Contopus borealis. Pp. 244-245 in R.F. Andrle and J.R. Carroll (eds.) The Atlas of Breeding Birds in New York State. Cornell University Press, Ithaca, NY.

Peterson, J.M. and C. Fichtel. 1992. Olive-sided flycatcher. Pp. 353-367 in Schneider, K. J. and D. M. Pence (eds.) Migratory Nongame Birds of Management Concern in the Northeast. U.S. Fish and Wildlife Service, Newton Corner, MA. 400p.