Northern Beardless-Tyrannulet Camptostoma imberbe

Tiny flycatcher found in Mexico and Central America. In the U.S. restricted to riparian woodland with dense understory and mesquite in the Southwest. Plain gray overall with inconspicuous pale wingbars and pale yellowish belly. Peaked bushy crown. Similar to Empidonax flycatchers but note bushy crest, blunter bill, and less obvious wingbars. Generally quite active. Often detected by song: a series of descending plaintive whistles "dee dee dee dee."