Northern Beardless-Tyrannulet

My guide, Jake Thompson, took me up into the very deserty Tumacacori Mountains, south of Green Valley on the I-19, southwest of Madera Canyon and the Santa Rita Mountains and southwest of (although much closer to) Santa Gertruda Lane and the Santa Cruz River. We drove several miles into the mountains over a pretty rough dirt road and eventually parked at the top of a hill. In a grouping of trees just off the dirt road Jake started to call a northern beardless-tyrannulet and I got some decent photos of it. 

Most flycatchers have bristles at the base of the bill which are referred to as the "beard." The "beardless" tyrannulet is lacking those bristles and thus, "beardless." 

Illustration from Birds of the World.

Range from Birds of the World. Another primarily Mexican and Central American bird with some inroads into southern Arizona. AI notes that they are small and have non-descript gray plumage and, thus, difficult to spot. They are usually located by their song, rather than by sight.