Bay-breasted Warbler Dendroica castanea
Flight call description A relatively low, sweet "dseet" with a muffled, buzzy quality. Nocturnal flight calls tend to be descending and more pure-toned than diurnal flight calls.
Fig.1. New York September 4, 1990 (WRE).
Bird in short flight.
Similar species Shorter and less buzzy than most other zeep calls. Blackburnian Warbler sounds equally short but is usually higher, sweeter, and less sibilant. Surprisingly similar in quality and pitch to American Redstart, though when heard well, clearly in the zeep category. See zeep calls.
Behavior Primarily a nocturnal migrant but engages in redetermined migration. Gives flight call regularly while perched and in flight during the day as well as during nocturnal migration.
Spectrographic description Measured calls (N=10) were 41.1-59.2 (52.0) mS in duration and in the 6.2-10.2 (7-8.5) kHz frequency range. The frequency track had a variable slope and was single-banded or with a faint second band. It was modulated with 1-3 (2) humps with a spacing of 18.1-24.7 (21.8) mS and a depth of 840-1700 (1300) Hz.