Blue-gray Gnatcatcher (Polioptila caerulea)
Spee Call: Thin and nasal. Given tirelessly by both sexes, it may serve a territorial function after singing has ceased for the season (Nice 1932).
Blue-gray Gnatcatcher Spee Call, April 11, 2010, Walworth County, WI.
Nice, M. M. 1932. Observations on the nesting of the Blue-gray Gnatcatcher. Condor 34:18-22.