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 or two cone opsin genes. Birds also seem to have lost the functionality of their right ovary. There are two ovary development-related genes, MMP19 and AKR1C3, that have disappeared in birds. The fact that a high number of genes related to spermatogenesis are evolving fast (which does not happen in those related to ovogenensis) suggest that males undergo a stronger selective pressure. The abundance of genomic data available nowadays has enabled research to elucidate the early evolution and divergence of bird groups, and has produced a much more detailed phylogenetic tree. Genomic research has shown that in order to make