WC warned readers that flycatchers of the genus Empidonax were difficult to tell apart. And perhaps the worst case is the Cordilleran Flycatcher, which is pretty much indistinguishable from its cousin, the Pacific Slope Flycatcher. WC doesn’t have any really good images of this species – they are all backlit. But here’s a side-by-side to illustrate the problem.
Good luck telling them apart. Which is why everyone but Peter Pyle depends on song and geography. These photos are both from September, so WC relied on geography. Flycatchers don’t sing that much in the autumn.
Cordilleran Flycatchers are primarily found in the Rocky Mountains, extending south in the Rockies through much of Mexico. while the Pacific-slope Flycatcher predominantly occurs in coastal ranges. Both species are commonly associated with cool, shady locations along waterways, where there is some openness under the canopy and opportunities for nest placement, although the Cordilleran occurs in desert areas, too.
The final word on classification of this species may not have been made. It turns out Pacific Slopes and Cordillerans sometimes hybridise, based on genetic sampling, where their ranges overlap, including in Northern Idaho. Good luck telling them apart there.
Whew. Emps. And there are lots more species, too. But WC will try some easier birds starting next week.
For more bird photographs, please visit Frozen Feather Images.