Common chiffchaff see", since this genus comprises species that spend much of their time feeding in trees, while "collybita" is a corruption of "kollubistes", "money changer", the song being likened to the jingling of coins. The common chiffchaff is a small, dumpy, 10–12 centimetres (4 in) long leaf warbler. The male weighs 7–8 grammes (0.28–0.31 oz), and the female 6–7 grammes (0.25–0.28 oz). The spring adult of the western nominate subspecies " P. c. collybita" has brown-washed dull green upperparts, off-white underparts becoming yellowish on the flanks, and a short whitish supercilium. It has dark legs, a fine dark bill, and short
Genomic evolution of birds possibility of genomic expansion in mammals and reptiles. Also, there is no such genomic loss in any vertebrate group as great as that of birds. Its possible that the early chromosomic fragmentation event that lead to the appearance of microchromosomes in birds significantly contributed to this gene loss. These fragmentation events must have taken place in a common ancestor of most birds, since approximately every two out of three species studied have at least 30 pairs of microchromosomes, 2n = 80 being the size of the average karyotype of birds (with the only exception the family Falconidae, which are 2n