Gouldian Finches are Australia's most spectacularly coloured grassfinches, and are perhaps the most spectacularly coloured of all Australian birds. They are small birds, with a bright green back, yellow belly and a purple breast. The facial colour is usually black, and is found in about 75% of the birds. Red-faced forms make up about 25% of the population, and rare, yellow-faced birds occur from time to time. The yellow colour results from a lack of red pigment in the red-faced birds. The males are brighter in plumage than the females. Young Gouldian Finches are dull ashy grey on the head and hind neck, becoming olive on the back and tail. The underparts are brown white, paler on chin, and have a faint yellow tinge on the belly. The upper bill is blackish and the lower bill is pinkish white. The end of the beak is tipped with red and there are pale nodules on the gape.