The Icterine Warbler's song is powerful, rapid and highly varied, a long and energetic stream of twittering and whistling phrases. The most striking feature is the clear imitations of other birds woven into the song, often species such as Barn Swallow, Common Starling and European Pied Flycatcher. A characteristic, ringing "dee-dlu-ii" recurs often. The song is considerably more powerful and rattling than the soft phrase of the Willow Warbler.