Cordilleran Flycatchers breed in cool coniferous or mixed mountain forests, usually near creeks, streams, or rivers. Such habitats, with both water and gaps of light in the forest, provide not just an abundance of insects and foraging perches but also nest sites. Like the closely related Pacific-slope Flycatcher, Cordilleran favors steep-sided ravines and canyons and sometimes nests on the sides of canyons rather than in trees. Common trees in these habitats include Engelmann spruce, lodgepole pine, ponderosa pine, Jeffrey pine, western bristlecone pine, western white pine, white fir, subalpine fir, and Douglas-fir, as well as quaking aspen, black cottonwood, water birch, canyon maple. Undergrowth plants include serviceberry, chokecherry, mountain alder, Gambel’s oak, New Mexican locust, willows, and hawthorns. During migration, Cordilleran Flycatchers may turn up in almost any well-vegetated, shaded area, especially where water and insects are present. In winter, they live in pine-oak forests in mountainous areas, including areas not near water, but there have been no studies of winter ecology in this species.Back to top
Cordilleran Flycatchers eat mostly insects that they capture in flight or pick from vegetation, such as caterpillars. They hunt largely from the interior of trees or large shrubs, usually near the middle of the tree, flying out to catch insects beneath the canopy. Most of their foraging occurs below 30 feet from the ground, and sometimes they pluck insects from the ground. Prey includes beetles, bugs, wasps, bees, flies, moths, leafhoppers, and spiders. They also eat elderberries and blackberries.Back to top
Nests are usually near flowing water, on rocky slopes, steep banks of streams, or in abandoned bird nests, mines, buildings, tree cavities, tree stumps, rotten logs, root masses of overturned trees, and set against the trunk on live tree branches.
The female builds a cup nest of moss and lines it with bark strips, rootlets, grasses, or hair, bound together with spiderwebs. Nests of the related Pacific-slope Flycatcher measure about 4.7 inches across, with the interior cup 2 inches across and 1.1 inches deep; those of Cordilleran are probably similar in proportions.
|Egg Description:||Creamy white with brown spotting concentrated at the larger end|
|Condition at Hatching:||Naked and helpless.|
Like other flycatchers of the genus Empidonax, males sing to mark a territory and attract a mate. They quickly chase other males that enter the territory (as well as other species of small flycatchers). Males sing frequently until they find a mate, then sing mostly at daybreak as nesting begins. Courtship displays are not known. Females build the nest alone and perform most incubation duties but both parents feed nestlings.Back to top
According to the North American Bird Breeding Survey, Cordilleran Flycatcher and Pacific-slope Flycatcher populations have declined an estimated 0.17% per year from 1968–2019. Partners in Flight estimates a global breeding population of 3.6 million Cordilleran Flycatchers and rates the species an 11 out of 20 on the Continental Concern Score, indicating a species of low conservation concern. Loss of montane coniferous forest habitat, both on breeding and wintering grounds, poses the most significant conservation threat to this species.Back to top
Lowther, Peter E., Peter Pyle and Michael A. Patten. (2016). Cordilleran Flycatcher (Empidonax occidentalis), version 3.0. In The Birds of North America (P. G. Rodewald, editor). Cornell Lab of Ornithology, Ithaca, New York, USA.
Partners in Flight. (2020). Avian Conservation Assessment Database, version 2020.
Rush, A.C., Cannings, R.J. and Irwin, D.E. (2009). Analysis of multilocus DNA reveals hybridization in a contact zone between Empidonax flycatchers. J. Avian Biol. 40(6): 614–624.
Sauer, J. R., D. K. Niven, J. E. Hines, D. J. Ziolkowski Jr., K. L. Pardieck, J. E. Fallon, and W. A. Link (2019). The North American Breeding Bird Survey, Results and Analysis 1966–2019. Version 2.07.2019. 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.