Common chiffchaff obvious wing bars; they include the willow, Bonelli's, wood and plain leaf warblers. The common chiffchaff has three still commonly accepted subspecies, together with some from the Iberian Peninsula, the Canary Islands, and the Caucasus which are now more often treated as full species. The common chiffchaff's English name is onomatopoeic, referring to the repetitive "chiff-chaff" song of the European subspecies. There are similar names in some other European languages, such as the Dutch "Tjiftjaf", the German "Zilpzalp" and Welsh "siff-saff". The binomial name is of Greek origin; "Phylloscopus" comes from "phyllon"/φυλλον, "leaf", and "skopeo"/σκοπεω, "to look at" or "to
Genomic evolution of birds bird bones. Something similar occurs with the respiratory system. In mammals, the total inner volume of lungs changes during ventilation. However, this does not happen in birds. They make the air circulate through their lungs by contracting and expanding their air sacs. Five genes are involved in this process in mammals and birds. Feathers are one of the most characteristic features of birds, alongside with the beak. Feathers are formed of α- and β-keratins. Compared to reptiles and mammals, α-keratin protein family has been reduced in birds, whereas β-keratins has expanded enormously. Since every major bird lineage possess at least