Blue Grosbeak Guiraca caerulea
Flight call description A low, very buzzy, often slightly descending "dzzzt" or "dzzzw".
Fig.1. Maryland September 12, 1994 (MO).
Bird in flight.
Similar species Painted Bunting is shorter and not as loud. Indigo Bunting is distinctly higher. Dickcissel is lower and drier. See buzz calls.
Behavior Primarily a nocturnal migrant but engages in redetermined migration. Gives flight call regularly while perched and in flight during the day and during nocturnal migration.
Spectrographic description Measured calls (N=10) were 80-150.9 (110.4) mS in duration and in the 4-8.7 (4.6-7.9) kHz frequency range. The frequency track was double-banded and level or slightly descending. It was modulated with 4.5-9 (7) deep, jagged humps with as spacing of 12.7-16.4 (14.1) mS and a depth of 1.1-2 (1.4) kHz.
Discussion Male calls average lower-pitched than female calls.