Least Flycatcher
Empidonax minimus
The least flycatcher is hard to distinguish from the other birds of its genus. The bird is one of the smallest of the genus Empidonax, measuring 12 to 14 cm in height with a wingspan of 19 to 22 cm and weighing approximately 10.3 g. Its plumage is dull olive-gray on its back and whitish on its belly, notably brighter than the other Empidonax birds. The least flycatcher's wings are lined with two white bars, and white rings contour its eyes. Its beak is short and the lower mandible is yellowish. Voice: The vocalization of the least flycatcher is often characterized as being dry and sounding like a piercing «che-bec» pushed with strength, the second syllable being louder than the first. During the hottest days of the summer, they often call incessantly. Singing is essential to the least flycatcher to establish and defend their territory.
ID text from Wikipedia, CC BY-SA 4.0
Willow Flycatcher
Empidonax traillii
Adults have brown-olive upperparts, darker on the wings and tail, with whitish underparts; they have an indistinct white eye ring, white wing bars and a small bill. The breast is washed with olive-gray. The upper part of the bill is gray; the lower part is orangish.
ID text from Wikipedia, CC BY-SA 4.0
Where you might meet both
Learn this pair in BeakBrain
Photo and call practice, free in any browser.
Play BeakBrainPhotos and recordings are credited to their authors under the licence shown. Full profiles: Least Flycatcher and Willow Flycatcher.