The Lesser Whitethroat's song is in two parts and highly characteristic. It opens with a short, soft and quiet introductory phrase of twittering notes, roughly "ti-ti-ti", and then shifts abruptly into a fast, dry and hard rattle on an even pitch — often rendered as "ti-ti-ti-krrekkrekkrekkrek". It is the dry, clattering final part that carries furthest and gives the bird away. The whole phrase lasts only a couple of seconds but is repeated over and over during the breeding season.
The song is delivered readily from the top of a tall bush, the tip of a tree branch or a telegraph wire — from a position with a clear view. The male sings diligently from its arrival in May right up to the end of June, most intensively during the light summer nights and early in the morning. Later in the season, in July, the