The Willow Tit's most usual call is a nasal, drawn-out "dää-dää-dää", often preceded by a few thinner notes: "tsi-tsi-dää-dää-dää". It differs markedly from the Marsh Tit's sharp, explosive "pit-chäää". The song is a series of clear, somewhat melancholy whistles. The call is the most reliable field mark.