With experience, a birder goes from "identifying" birds to "recognizing" them. When it comes to the Flycatcher family, I am still in "identifying" mode. I have to make notes of the field marks of each bird, and then look in my Sibley's Field Guide to figure it out.
Several flycatchers in the Epidonax genus are so hard to tell apart looking through binoculars that their unique sound is often the only way. I've been pulling out my Zune MP3 player recently with the BirdJam software on it to help me. So far at Avimor I am pretty confident in "identifying" Western Wood-Pewees, Willow and Dusky Flycatchers. I now "recognize" the call of the Western Wood-Pewee very well.
Check out these tips to identifying Idaho Flycatchers. Click on the name of the bird to go to All About Birds where you can also listen to the calls they make.
Western Wood-PeweeWillow FlycatcherDusky FlycatcherHammond's FlycatcherGray FlycatcherOther Flycatcher's you may see regularly in Idaho are Say's Phoebe, Western Kingbird, and Eastern Kingbird. Less frequently you may spot a Cordilleran, Pacifc-Slope, Ash-throated or Least Flycather.