The European greenfinch or simply the greenfinch (Chloris chloris) is a small passerine bird in the finch family Fringillidae.The European greenfinch is 15 cm (5.9 in) long with a wingspan of 24.5 to 27.5 cm (9.6 to 10.8 in). It is similar in size and shape to a house sparrow, but is mainly green, with yellow in the wings and tail. The female and young birds are duller and have brown tones on the back. The bill is thick and conical. The song contains a lot of trilling twitters interspersed with wheezes, and the male has a “butterfly” display flight. Male greenfinch birds exhibit higher degrees of fluctuating asymmetry. The development of bones of males may be more easily disrupted than that of females.