Pacific-slope Flycatchers in Borrego Springs

Pacific-slope Flycatchers are perhaps the "easiest" of the Empidonax to identify in western North America. Or, at least they were,... back when they were named Western Flycatchers. Then they got split into Pacific-slope and Cordilleran Flycatchers, which are identical in plumage, but the male's position note is supposedly different.

Let's try again...

Pacific-slope Flycatchers are perhaps the "easiest" of the Empidonax to identify in most of California and western Oregon, western Washington, and SW British Columbia. If you live from Arizona to Idaho, then forget it.

This is not how I wanted this post to go. One more time...

Western Flycatchers are perhaps the "easiest" of the Empidonax to identify in western North America. Better? No?

Oh, forget this....

Pacific-slope Flycatchers are hard to identify--as are all Empidonax flycatchers. They are small, greenish, and with generally white eye rings and wing bars. Identification in the field depends upon excellent looks at subtle field marks. Museum specimens are easier if you accurately measure wing, tail, and bill. On the breeding grounds the songs are distinctive.

The yellow throat and the large teardrop-shaped eye ring separates "Western Flycatchers" (Pacific-slope and Cordilleran) from other Empids in the West (Hammond's, Dusky, Willow, Gray, Least). In the East, you have  the similar Yellow-bellied and others to confuse you. There are about 15 species of Empids from Canada all the way to Costa Rica for your viewing pleasure (or frustration).

I came across a bunch of these in migration last month in Borrego Springs. The mountains, separating the coastal slope of San Diego County from the harsh desert to the east, had blocked a storm front coming in from the west. Migrants flying at night encountered strong headwinds and potential rain and dropped to the ground to find protection. They found the dry Anza-Borrego desert and oh, what's that? A bit of green mesquite surrounding the Borrego Springs waste treatment ponds.

It was very windy, so these tired travelers sought refuge on the lee side of the mesquite clumps and found some flying insects near the ground to feed upon for breakfast.

I spent quite a bit of time photographing these and Willow Flycatchers.

Pacific-slope Flycatcher. Borrego Springs, California. May 25, 2019.