Common chiffchaff one of the first avian signs that spring has returned. Its call is a "hweet", less disyllabic than the "hooeet" of the willow warbler or "hu-it" of the western Bonelli's warbler. The song differs from that of the Iberian chiffchaff, which has a shorter . However, mixed singers occur in the hybridisation zone and elsewhere, and can be difficult to allocate to species. When not singing, the common chiffchaff can be difficult to distinguish from other leaf warblers with greenish upperparts and whitish underparts, particularly the willow warbler. However, that species has a longer primary projection, a sleeker, brighter appearance
Canary Islands chiffchaff and a longer tail. Its underparts have a brownish-buff tone, especially on the flanks and breast, and the upperparts are darker brown than the common chiffchaff. Many calls are similar to the common chiffchaff but the song lacks the metronomic quality of that species and is harsher, shorter and more varied and with a faster delivery. The Canary Islands chiffchaff occurs in most habitats from coastal gardens to high altitude vegetation but is absent from semi-desert scrub at lower altitudes. In the breeding period, January to June, the Canary Islands chiffchaff is territorial and is found singly or in pairs,