Whilst the coloured Gouldian Finch (Chloebia gouldiae) has three separate forms (colour variants), the juvenile of the species are light grey-brown in colour, olive-grey back and a small white throat patch.
As adults, the most common colour is the black-headed form, followed by the red-headed form, whilst the yellow-headed form is the rarest.
The following images of the Gouldian Finches at a water source just south of Larrimah in the Northern Territory, show a number of immature birds, as well as some starting to gain their colouration.
The following photos are of the immature Gouldian Finch, starting to colour up and will be the red-headed form of the species.
The following adult Gouldian Finch with an immature bird.