Common chiffchaff Common chiffchaff The common chiffchaff ("Phylloscopus collybita"), or simply the chiffchaff, is a common and widespread leaf warbler which breeds in open woodlands throughout northern and temperate Europe and Asia. It is a migratory passerine which winters in southern and western Europe, southern Asia and north Africa. Greenish-brown above and off-white below, it is named onomatopoeically for its simple "chiff-chaff" song. It has a number of subspecies, some of which are now treated as full species. The female builds a domed nest on or near the ground, and assumes most of the responsibility for brooding and feeding the chicks, whilst
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