The song is the species' most characteristic feature: a persistent, buzzing, insect-like "zr-zr-zr-zr" in long, rhythmic series that can continue for a very long time without a break. The sound recalls a grasshopper or a sewing machine and is delivered above all at dusk and during the night. As with its relatives the Savi's Warbler and the Common Grasshopper Warbler, the persistent, mechanical song is the best way to detect the species.