Dusky Flycatcher Life History

Habitat

In western mountains, Dusky Flycatchers nest in open, brushy environments such as thickets, mountain chaparral, aspen groves, and shrubby stream corridors. Usually these places have at least some scattered trees. They move into disturbed habitats readily, including old burn areas, powerline corridors, the edges of ski runs, so long as they feature a combination of brushy habitat and some trees. In the understory, willows, alders, laurels, manzanitas, bitterbrush, deerbrush, sage, chokecherry, serviceberry, currants, plums, wild cherry, hazel, dogwood, mallow ninebark, and mountain mahogany are common plants, while trees include pines, firs, Douglas-firs, junipers, spruces, aspens, birches, maples, oaks, and cottonwoods. They migrate in spring and fall (usually later in spring and earlier in fall than Hammond’s Flycatcher), passing through many habitats from brushy stream corridors and chaparral up through high elevations. For example, during spring migration in Arizona, Dusky Flycatchers might be more numerous in mountains than in valleys. Even green spaces in cities may harbor a few migrants. On the wintering grounds in Mexico and Central America, Dusky Flycatchers select habitats similar to their breeding grounds, mostly brushy areas in oak scrub and pine-oak habitats, arroyos, and arid scrub where vegetation is relatively tall and dense. They avoid grazed environments, but in some areas move in soon after grazing ceases and shrubs regenerate.

Food

Dusky Flycatchers eat mostly insects that they catch in flight. They perch quietly, scanning the environment, then fly quickly upward or outward to capture the insect. They occasionally pluck insects from the ground or from vegetation as well. During the breeding season, most Dusky Flycatchers forage in brushy areas or the lower levels of trees. Their known prey items include butterflies, moths, caterpillars, wasps, bees, grasshoppers, damselflies, bugs, flies, and beetles. Once the prey is captured, the birds return to a perch to consume it, sometimes first whacking it against a branch to subdue it or soften it up.

Nesting

Nest Placement

The nest is set in a tree or shrub crotch about 3–17 feet (average 6.6 feet) off the ground, usually in an area of dense undergrowth that has plenty of perches for hunting.

Nest Description

The female builds the nest, a cup of woven grasses and plant material lined with grass, hair, plant down, lichen, and feathers. Nests measure on average 3 inches across and 3 inches tall, with interior cup 2 inches across and 1.4 inches deep.

Nesting Facts

Behavior

Once arrived on the breeding grounds, male Dusky Flycatchers establish a territory (around 2 acres) by singing from perches around the territory. They perform fluttering song flights in which they spiral downward from treetops, delivering a rapid series of call notes. Females arrive in breeding areas a week or so later than males. Males sing vigorously through much of the day until finding a mate, and then sing less often (and sometimes sing shorter songs) during chick-rearing. Males perform a courtship display in which they raise the head, open and flutter the wings, and raise and quiver the tail while hopping between branches and calling. Females inclined to mate perform a similar display, then crouch. Dusky Flycatchers appear to be monogamous in their mating system. Both members of the pair feed the young, but only the female incubates. Curiously, in one study, about 10% of nests were attended by two males and one female. Both sexes defend the territory against other Dusky Flycatchers, threatening trespassers first by pumping and spreading the tail, fluffing the body plumage, raising the crest, and snapping the bill. If threat displays do not suffice, aerial chases and physical combat follow. They also sometimes threaten and drive out Gray Flycatchers that enter the territory.

Conservation

Dusky Flycatcher populations remained roughly stable between 1968 and 2015, according to the North American Breeding Bird Survey. Partners in Flight estimates a global breeding population of 8.8 million and rates the species an 11 out of 20 on the Continental Concern Score, indicating a species of low conservation concern. Dusky Flycatchers benefit from some forms of habitat disturbance, even some types of logging that increase shrubby habitats within forests. Their populations suffer when shrublands are grazed or converted to agricultural use, and when stream corridors are cleared and channelized.

Credits

Lutmerding, J. A. and A. S. Love. (2020). Longevity records of North American birds. Version 2020. Patuxent Wildlife Research Center, Bird Banding Laboratory 2020.

Partners in Flight (2017). Avian Conservation Assessment Database. 2017.

Pereyra, Maria E. and James A. Sedgwick. (2015). Dusky Flycatcher (Empidonax oberholseri), version 2.0. In The Birds of North America (P. G. Rodewald, editor). Cornell Lab of Ornithology, Ithaca, New York, USA.

Sauer, J. R., D. K. Niven, J. E. Hines, D. J. Ziolkowski Jr., K. L. Pardieck, J. E. Fallon, and W. A. Link (2017). The North American Breeding Bird Survey, Results and Analysis 1966–2015. Version 2.07.2017. USGS Patuxent Wildlife Research Center, Laurel, MD, USA.

Sibley, D. A. (2014). The Sibley Guide to Birds, second edition. Alfred A. Knopf, New York, NY, USA.

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