Aka: Normal / Grey / Wild-type.
Inheritance: The color is born from different types of wild-type alleles that excluding couple cases are dominant to in relation to their mutations.
The cockatiels you can see in Australia in the wild are grey. This color is the beginning of all the nowadays mutations. Every color mutation of a cockatiel are modifications of the normal wild colored grey’s different alleles and have been caused by reducing, increasing or completely removing certain color areas. You can separate orange/red (cheeck patces), yellow (the face mask and the tail) white (the base color, seen in grey birds in the white wing bar) and grey which is the main color of the cockatiel’s body.
It is important to understand that the normal grey isn’t a result of just one allele. It is caused by several genes. When one of these genes mutates, a new allele is born and that allele changes the characteristin that the previous gene was affecting to. For example if the gene alteres the psittacine pigment and a mutation is born, the mutation changes the way that the yellow and red colors are shown. We call the original genes as “wild-type”. Wild-type genes are very often dominant towards their alleles.
On left there’s a grey male. Photo: George Steinz / georgesteinz.nl
Gender definition and chicks
The grey male’s plumage has the main color of grey. It still has white wing bars and bright yellow face mask. The ear hole is covered with bleached red cheek patches. The tail of the male is black from the underside and silvery grey overside.
The hen looks quite much like the cock but it has more greyish face from which the cheek patch and the yellow mask are bleeding through. The tail of the female is pale yellow but the feathers have darker stripes on them horizontally. Then hen also has light spots under its wings.
The babies are born with yellow baby down and dark bruise colored eyes. As they get their plumage, each youngling looks like a female. This is a camouflage. Around the age of six months cockatiels start reaching puberty and get their first molt, turning males yellow faced and dark tailed. Females will remain as they were as babies.
On right there’s a normal grey female. Photo: George Steinz / georgesteinz.nl
A pure grey means a normal grey cockatiel that doesn’t carry any mutations as splits. Even though the normal grey is most often met coloration, a pure grey is very rare: there is almost always either some alleles or their leftovers. Most often the gene is pied that can be found as split in most of the cockatiels, globally. Pure greys are special because they don’t have anything “superfluous” in their genotype. Because pure greys won’t transmit any mutations they are very important when working with some new mutation or rare colors because you can more easily prune unwanted genes away from the line. For example dominant silvers need pure greys to their lines to maintain their dark skullcap better and keeping pied and other such genes away.
And then of course, because humans are what we are, there is always a possibility that we screw things up. And it’s not possible to export anything from Australia anymore. For such case it is crucial to have stocks of pure greys to help us return to the starting point if something goes wrong. So: value the pure greys.