Common chiffchaff and generally pale legs. Bonelli's warbler ("P. bonelli)" might be confused with the common chiffchaff subspecies "tristis", but it has a plain face and green in the wings. The common chiffchaff also has rounded wings in flight, and a diagnostic tail movement consisting of a dip, then sidewards wag, that distinguishes it from other "Phylloscopus" warblers and gives rise to the name "tailwagger" in India. Perhaps the greatest challenge is distinguishing non-singing birds of the nominate subspecies from Iberian chiffchaff in the field. In Great Britain and the Netherlands, all accepted records of vagrant Iberian chiffchaffs relate to singing males.
The Life of Birds matter had been covered before by Attenborough within "Life on Earth", in an episode entitled "Lords of the Air", but now he was free to expand on it. However, by his own confession, despite being especially fascinated by one family, the birds of paradise, Attenborough was not an expert in ornithology. Nevertheless, the notion of an entire series devoted to the creatures excited him, as he would be able to not only communicate his findings to the viewing audience, but further his own knowledge as well. From the outset, the production team were determined that the sound of birds calling