Vesper Sparrow Pooecetes gramineus
Flight call description A rising "hvsit" with a slightly husky quality. Sometimes a softer "hvsee".
Fig.1. Texas November 15, 2000 (WRE).
Bird in flight with Red-winged Blackbirds calling in the background.
Similar species See White-crowned Sparrow. Some variations similar to Chipping Sparrow, but huskier and not as abrupt at the end. Typically longer than the "double-banded up-seep" warbler group but shorter examples may be very similar. See Ovenbird 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 during nocturnal migration.
Spectrographic description Measured calls (N=9) were 46.2-90.7 (71.1) mS in duration and in the 6.1-10.3 (6.6-9.3) kHz frequency range. The frequency track was double-banded and rising, usually with a distinct upward bend at the beginning. Some calls showed very fine modulations with a spacing between humps of 4.0-4.5 (4.3) mS and a depth of 200-300 kHz.