Swainson's Warbler Limnothlypis swainsonii
Flight call description A high, clear, rising "seeth" with a piercing quality (note limited sample size: see Discussion).
Fig.1. Virginia July 19, 1995 (MO).
Foraging bird. Note strong vegetation reflection.
Examples Diurnal
Similar species Similar to Ovenbird and Prothonotary Warbler but may be higher and clearer. See short rising seeps.
Behavior Primarily a nocturnal migrant but presumed to engage in redetermined migration. Gives flight call occasionally while perched and on short flights during the day. Presumably gives flight call during nocturnal migration.
Spectrographic description Measured call (N=1) was 57.8 mS in duration and in the 7.5-9.1 kHz frequency range. The frequency track was single-banded and showed an initial rising section followed by a more level or downward-arched section of greater intensity. The call was obscurely and irregularly modulated throughout with an average spacing of 5 mS between humps.
Discussion Our experience with this species' flight call is limited to brief encounters with four individuals on the breeding grounds in Virginia and North Carolina, and a migrant at the Dry Tortugas in the Florida Keys.