The Bohemian Waxwing has a distinctive, sustained trilling and ringing call, often rendered as a thin "sirrr". From a flock comes a collective, bell-like tinkling sound that is one of winter's most characteristic bird calls. The call is often heard before the birds are seen. The high, silvery trill amounts to no real song and at a distance can be reminiscent of jingling bells, so that a flock in a bare winter tree gives itself away long before the pinkish-buff birds can be picked out against the sky.