by Gail Cleveland
Oh, no! The Bird of the Month is one of those small, gray-green flycatchers that no one can tell apart but the experts. Yes, it is one of the genus Empidonax, Empidonax occidentalis to be specific, but read on. You may be able to find the joy in identifying a Cordilleran Flycatcher next spring after reading about and listening to these little flycatchers that inhabit northwestern Montana.
The most comprehensive discussion of the Empidonax flycatchers that I have found is Ken Kaufman’s 2011 version of Field Guide to Advanced Birding. Out of the 12 species of this genus, we are likely to see and hear Willow, Alder, Hammond’s, Dusky, Least and Cordilleran in Northwest Montana during the breeding season. As Kaufman points out, visual identification of these little gray birds with eye rings and wing bars can be difficult. However, during the breeding season, their songs and vocalizations can be most helpful in identification. For their vocalizations, go to Cornell Lab of Ornithology’s website: www.AllAboutBirds.org. Also, iBird Pro and the Sibley eGuide to the Birds of North America apps have easy to access vocalizations.
My interest in Cordilleran Flycatchers began when trying to find them for the Flathead Audubon Birdathon. They are harder to find in the area than three more common Empidonax: the Dusky, Hammond’s and Willow. One of the spots that the area experts mention finding them each year is on the Columbia Mountain trail or up the small streams from the Badrock Canyon pullouts. This seems to be their preferred habitat: “riparian forests adjacent to conifers, conifer forests with dense understory of shrubs, and canyons or road cuts that provide cliffs with banks for nesting,” according to Birds of Montana by Marks, Hendricks and Casey. One of the early specimens taken in the state was found near Columbia Falls by R. S. Williams in 1896.
One of my memorable early sightings was before 1989 along the Fisher River in a boggy roadside area in Lincoln County. At this time the Cordilleran Flycatcher was known as the Western Flycatcher. In 1989, the species was divided into two separate species: Pacific-slope and Cordilleran. The division was based on vocalization, ecology and DNA differences. However, recent studies suggest that interbreeding exists between the two. Whether they are two distinct species is still in question.
But how does one tell if it is a Cordilleran rather than another Empidonax? One of the most distinguishing features is the eye ring. It is quite bold with a distinctive teardrop shape at the back of the eye. A second feature is its head, which appears large and peaked with a large, broad bill that has a yellow-orange lower mandible. Other features are a long, narrow tail and dingy white wing bars.
Behavior is similar to other small flycatchers. Tending to like shady perches, the Cordilleran flies out to catch insects, usually coming back to another branch before it flies out again. It can also glean insects from leaves or on the ground. Insects are its main diet; therefore, they fly south, wintering mostly in Mexico and returning in late March to early June.
The distinctive features of the Cordilleran song include its squeaky, high-pitched sound and three distinct parts with pauses in between. One must really listen to the vocalizations. One of the problems of the Empidonax is trying to find the right letters and words to describe their sounds. To most birders, bird songs such as the Olive-sided Flycatcher’s, whose song translates to “Quick, three beers,” or the Willow Flycatcher’s with its “Fitz-bew,” are easier to remember and identify than the Cordilleran Flycatcher song. In order to identify its song in the field, you should listen to recordings of the Dusky, Hammond’s and Cordilleran flycatchers until you can recognize the difference. Sonograms can be helpful along with listening to recordings.
Last summer my husband and I saw and heard a Cordilleran Flycatcher at the Columbia Mountain sight as well as at Little Bitterroot Falls on the road from Highway 2 to Hot Springs. Our last sighting was a real surprise. On a trail above Little Therriault Lake in the Ten Lakes Scenic Area at 6400 feet, we heard an unusual call, which turned out to be a Cordilleran. It sat out in the open long enough for us to get a visual identification, using the eye-ring, the peaked head and the lower mandible as clues, along with the call. Amazingly, he sat still long enough for me to get a picture! It was one of those “Bird Moments” that makes us keep looking for birds, even the hard to identify ones like the Empidonax genus.