Prothonotary Warbler Protonotaria citrea
Flight call description A high, rising "sweet" with a sweet, sibilant quality.
Fig.1. Maryland August 31, 1994 (MO).
Bird in flight.
Similar species Similar to Ovenbird but usually longer and not as piercing. American Redstart can be similar but either has a two-parted character or is less distinctly rising than Prothonotary Warbler. Yellow-rumped Warbler is lower and not as sweet. See Swainson's Warbler, White-crowned Sparrow, and short rising seeps.
Behavior Primarily a nocturnal migrant but engages in redetermined migration. Gives flight call regularly while perched and in flight during the day and presumably during nocturnal migration.
Spectrographic description Measured calls (N=13) were 53.8-74.1 (63.1) mS in duration and in the 5.7-10.4 (6.5-9.1) kHz frequency range. The frequency track was single-banded or with a faint second band. It was rising and slightly upward-arched and often had a moderately distinct downward hook at the end. Calls were modulated throughout with irregular squiggles having a spacing of 5.5-12.1 (9.4) mS and a variable depth.