Nocturnal Singing in Grassland Birds

Abstract

We conducted unlimited radius point counts from March–July 1999 at sunrise, dusk, and night to document the relative frequency of nocturnal singing by grassland birds at Prairie Ridge State Natural Area, Jasper County, Illinois. Most grassland species were recorded singing at all times of day, but least commonly at night. Short-eared Owls (Asio flammeus) and American Woodcock (Scolopax minor) were only recorded at dusk and night. Sedge Wrens (Cistothorus platensis) and Henslow's Sparrows (Ammodramus henslowii) were most frequently recorded at night and least frequently at sunrise. Only 57% of all the breeding species recorded by our surveys were detected on June sunrise counts corresponding to the timing of the North American Breeding Bird Survey.