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
A Photographic Guide to the Birds of Indonesia with one or more photographs as well as a distribution map. The taxonomy and nomenclature in the first edition followed "The Birds of Indonesia: a Checklist" by Peter Andrew from 1992; this was the most used checklist at the time, using the so-called ‘crows-last’ sequence. The book was a companion to "A Photographic Guide to the Birds of Southeast Asia" which was published the previous year, in 2000. However, this volume used a different checklist as a reference with a ‘buntings last’ sequence. "A Photographic Guide to the Birds of Indonesia" was reprinted several times during the following years, but