Northern Waterthrush Seiurus noveboracensis
Flight call description A buzzy, distinctly rising "zweedt". A lazy, relatively low-pitched note becoming louder and buzzier at the end.
Fig.1. Virginia September 19, 1993 (MO).
Bird in flight.
Similar species Usually distinctive but see Kentucky and Magnolia Warblers. Similar to Louisiana Waterthrush but more distinctly rising, softer at the beginning, and with a finer, drier buzz. Longer and more distinctly rising than most other zeep calls. See zeep calls.
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, and during nocturnal migration.
Spectrographic description Measured calls (N=17) were 61.7-93.6 (78) mS in duration and in the 6.2-9.4 4-9 (6.2-8.1) kHz frequency range. The frequency track was single or double-banded and rising. It was modulated with 3-9 (6) humps with an average spacing of 8.6-13.3 (11.2) mS between humps and a depth of 0.4-1.3 (0.7) kHz. Spacing and depth typically increased in magnitude toward the end of the call.