Aiken states that in the eastern foothills of the Rocky Mountains this bird sometimes outnumbers all other Warblers combined. It is a shy and timid species, darting into its place of concealment with a sharp note of alarm. In summer it frequents scrubby hillside growth up to an elevation of about 7500 feet but during migrations it is found in pine forests, cottonwoods and willows. In Arizona, Howard says, they keep almost entirely in the underbrush where they are continually on the move, uttering a quick chirp as if in distress. The male is very musical during the nesting season, uttering his swee notes as he skips thru the bushes in search of food. Having satisfied his appetite he mounts to the tip of some nearby tree and repeats, at regular intervals, a song of remarkable fulness for a bird of such minute proportions.