Song: The long call display, performed in a stiff-winged flight with back and neck arched, is a strident, rhythmic series of "tick-ka, tick-ka, tick-ka" calls often ending in a decelerating "turrrrr".
Sound: Herman van Oosten (http://www.xeno-canto.org/33354); 2009 Apr 23; Netherlands; Dune reserve near Castricum, Noord-Holland; Call;