- Scientific name: Contopus cooperi
Species of Greatest Conservation Need (MA State Wildlife Action Plan)
Description
Olive-sided flycatcher
The olive-sided flycatcher is a somewhat large flycatcher (18-20 cm [7-7.8in] in length) with a generally dull plumage: brownish gray above, white on the throat, chest and belly, and gray on the flanks. Its whistled song, phonetically described as quick, THREE BEERS, is diagnostic.
Life cycle and behavior
The olive-sided flycatcher is a songbird often associated with high-elevation habitats in Massachusetts, particularly coniferous swamps and bogs where it can be found in migration (or occasionally in breeding situations), perched atop exposed snags and sallying forth to capture flying insects. Breeding pairs build a small cup nest at the end of a horizontal branch (typically of a conifer). 3-4 eggs are laid and incubated for 15-19 days, and the chicks remain in the nest for an additional 15-19 days. The primary diet throughout the year is insects.
Population status
Olive-sided flycatchers are currently extremely rare breeders (now nearly absent) in Massachusetts and uncommon autumn migrants.
Distribution and abundance
Breeding olive-sided flycatchers were once distributed across Massachusetts, occurring in every county except Nantucket. In the eastern parts of the state, they favored wetlands associated with pine barrens, and bogs and coniferous swamps in the central and western parts of the state. However, by the mid-20th century, olive-sided flycatchers began a dramatic range retraction in the state and currently are found breeding only in very limited occurrences in north central and western Massachusetts.
Massachusetts Breeding Bird Atlas 1 surveys found that olive-sided flycatchers still persisted at a handful of breeding localities. The Taconic Mountains and Marble Valleys had several occupied blocks, but the Berkshire Highlands region was the center of the olive-sided flycatcher’s thin Massachusetts distribution. More than half of all breeding records came from this region’s high-altitude wetlands. The only other place in the Commonwealth where breeding olive-sided flycatchers were found was Mount Watatic at the northern edge of the Worcester Plateau.
Olive-sided flycatchers moved further toward extirpation in Massachusetts by Atlas 2 (2007-2011). Not a single confirmed instance of breeding was reported anywhere in the state, and the only probable report came from the Berkshire Transition, where there had been no breeding evidence in Atlas 1 (1974-1979). The Berkshire Highlands were still host to more olive-sided flycatcher sightings than any other region, but, where it was formerly present in 11 blocks, it was this time recorded in only 5.
Breeding Bird Survey data shows that the population of olive-sided flycatcher has experience an overall decline of 4.53 percent annually in Massachusetts from 1966 to 2013. The range-wide trend is an annual decline of 3.48 percent annually (1966-2013).
Habitat
Olive-sided flycatchers are primarily associated with montane and northern coniferous forests, especially forests with openings such as bogs, meadows or forestry cuts. In Massachusetts, this relegates olive-sided flycatchers to the western and north-central parts of the state, though historically they also inhabited wetlands associated with pine barrens in the eastern part of the state. Recent studies have shown a strong tendency for olive-sided flycatchers to inhabit frequently burned areas across their range, which suggests that their range retraction in Massachusetts may be in part due to fire suppression in historic barrens.
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Threats
Specific reasons for the overall decline of olive-sided flycatchers in Massachusetts are not clear, but alteration of wintering habitat (deforestation in the Andes) is thought to be one factor in their range-wide decline.
Studies suggest that olive-sided flycatchers favor post-fire habitats for breeding, suggesting that their decline in Massachusetts could partly be the result of fire exclusion. These studies also suggest that olive-sided flycatchers are using recently harvested forests as a proxy for post-fire habitats, and as a result, are experiencing less reproductive success due to increased predator presence, reduced prey availability, and increased parasitism. Fire suppression in Massachusetts’ pine barrens is one possible explanation for their modern absence from these areas.
Climate change is expected to shrink the montane and northern boreal habitats that olive-sided flycatchers currently rely upon in Massachusetts.
Conservation
It is unclear exactly what micro-habitat attributes are necessary for successfully breeding olive-sided flycatchers, but disturbance on some level appears to play a role in shaping ideal habitat. Understanding the role of natural disturbance, especially on a historic scale, in occupied patches is important for management considerations. Where appropriate, the introduction of prescribed fire and/or forest management may be beneficial to breeding olive-sided flycatchers, but these actions should be approached with caution and employed on a site-by-site basis.
References
Altman, B., and R. Sallabanks. 2012. Olive-sided flycatcher (Contopus cooperi), The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology; Retrieved from the Birds of North America Online: http://bna.birds.cornell.edu/bna/species/502
Breeding Bird Atlas Explorer (online resource). 2015. U.S. Geological Survey Patuxent Wildlife Research Center. <2015-02-15>. http://www.pwrc.usgs.gov/bba. Data compiled from: Massachusetts Breeding Bird Atlas 2007-2011
Sauer, J.R., J.E. Hines, J.E. Fallon, K.L. Pardieck, D.J. Ziolkowski, Jr., and W.A. Link. 2014. The North American Breeding Bird Survey, Results and Analysis 1966 - 2013. Version 01.30.2015 USGS Patuxent Wildlife Research Center, Laurel, MD
Veit, R.R,, and W.R. Petersen. 1993. Birds of Massachusetts. Massachusetts Audubon Society, Lincoln MA.
Contact
| Date published: | April 4, 2025 |
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