The Migrants are Starting to Arrive: Pacific-Slope Flycatcher on the Tuolumne River

Sometimes I'm just really lucky. I'm no expert, not by a longshot, and though I can recognize most of the common species in our area, I'm at a loss when some of the rarer migrants come through. I learn most by repetition, and if I've seen a bird only once or twice previously, I won't be able to pick it out readily. I have to get pictures and pull out the field guides.

That's what happened yesterday. I was keeping a careful eye out for Buntings and Grosbeaks, my most exciting recent discoveries, when another bird landed in the branches in front of me long enough for two quick shots. The distinctive shape of the eye-ring and the bi-colored bill nailed it: a Pacific-slope Flycatcher (Empidonax difficilis). I've only seen it once before, during the spring migration.

Pacific-slope Flycatcher might seem a slightly clumsy name, but how about Cordilleran Flycatcher? Those are fairly modern terms for a bird that was first described in 1858. Until 1989 the two species were considered to be one: the Western Flycatcher, a more normal-sounding name. The problem is that the species split was based on vocalizations and breeding habits, and in practice the birds are very difficult to tell apart from each other. Some sources on the web suggest that the species split was premature.

In any case, I was lucky to identify this bird as a flycatcher, period. But I was really happy to get a fairly sharp picture (compare it to my last image here), and maybe next time I'll recognize it on sight!.

It Must Be Flycatcher Week: Pacific-slope Flycatcher on the Tuolumne River

I've been on a steep learning curve this week regarding flycatchers. For the three years I've been following birds on the Parkway Trail on the Tuolumne River I've seen a fair number of flycatchers, principally Black Phoebes who stick around all year, and Ash-throated Flycatchers, who have been fairly common sights during the summer months. Then, in the space of just two and a half weeks, I observed not one, not two, but three new species of flycatcher. First there was the Western Wood-pewee on May 7. Then two days ago, I sighted an Olive-sided Flycatcher that I hesitated to even report out of insecurity over my identification skills (plus it's kind of rare down here in the valley).

And then there was this morning. I'm looking for Olive-sided Flycatchers, or Western Wood-pewees, or Ash-throated Flycatchers (I always know I'll see the Phoebes; I know where they live). But the bird that appeared was none of those. It had a different color scheme, and it had a white ring around the eye. I hit the books (again) and realized I had photographed a Pacific-slope Flycatcher (Empidonax difficilis). The picture is not great, but I'll catch better ones next time! Or maybe it'll be a Hammonds Flycatcher, or a Willow Flycatcher. Apparently it is that kind of a week.

As their name suggests, these flycatchers are found in the extreme west in a line that extends from Mexico to southern Alaska and Canada. They are closely related to the Cordilleran Flycatchers, which are found farther to the east. They were once thought to be the same species. They eat...flies (and other insects).