American Redstart Setophaga ruticilla
Flight call description Typically an abrupt, upslurred "tswee" with a subtle two-parted character. Also a more distinctly two-parted "tswit" or a nearly monotone "tsee". Most variations have a distinctive clear, sweet quality.
Fig.1. Virginia August 24, 1993 (MO).
Bird calling in flight.
Similar species Usually distinctive but some variations may be similar to Ovenbird. See Prothonotary Warbler, Chipping Sparrow, and short rising seeps.
Behavior Primarily a nocturnal migrant but engages in redetermined migration and limited resumed migration. Gives flight call regularly while perched and in flight during the day as well as during nocturnal migration.
Spectrographic description Measured calls (N=20) were 49.3-78.8 (63.7) mS in duration and in the 5.4-10 (6.6-8.5) kHz frequency range. The frequency track was typically single-banded but sometimes double-banded. It typically consisted of a fairly steeply descending portion followed by a longer rising and variably downward-arched portion, often forming a "V" or checkmark shape. Some variations were flatter. Often present in the second portion of the call were various bends or modulations. Modulations had a spacing of 4.1-7.2 (6.2) mS and a depth of 0.2-0.7 (0.6) kHz.