Fox Sparrow Passerella iliaca
Flight call description A clear, piercing, somewhat lisping, slightly upward-arched "tsueeth".
Fig.1. Maryland March 22, 1992 (MO).
Perched bird.
Similar species Very similar to Song Sparrow but typically louder and more upward-arched. Similar to Chipping Sparrow but longer and less distinctly upward-arched. See White-throated, White-crowned, and Harris's Sparrows.
Behavior Nocturnal migrant. Gives flight call regularly while perched, particular around dawn and dusk, and in short flights during the day and in nocturnal migration.
Spectrographic description Measured calls (N=19) were 87-120.5 (108.6) mS in duration and in the 6.3-10.7 (7.3-9.7) kHz frequency range. The frequency track was double-banded (either band sometimes faint) and upward-arched, often with a slight downward bend at the end creating a flattened "S" shape. The low point was typically about one quarter to one third of the way through the call, and the widest gap between bands was typically at the low point.