Several questions have been received regarding the new color varieties. One of the recent variations is a group of mutations that lightens the normally orange colored cheek patch.
Whiteface was the first mutation to be successfully reproduced that had a dramatic effect on the cheek patch color. Whiteface is an autosomal recessive mutation that removes all yellow and orange coloration. It has been noted that some splits to whiteface will have a lighter orange cheek patch. The cheek patch is still orange but lacks some of the intensity that would be exhibited by a cockatiel that has no splits to whiteface. This reduction of color in the cheek patch has also been noted in cinnamon. This type of reduction of intensity is subtle and should not be confused with the new mutations that produce a peach or yellow colored cheek patch.
Three mutations have occurred that cause a peach or yellow colored cheek patch. These are the Pastel, Sex Linked Yellow Face and Dominant Yellow Face. The terms yellow face and yellow cheek are both used to describe these mutations. There are differences in the cheek patch color between these three mutations, but a written description here would be premature since a judging standard has not been created yet. Since they look very similar, pedigree records become a necessity!
Sex linked yellow face follows the same rules of inheritance as pearl and lutino. In selecting Mates for sex linked yellow face cockatiels it is extremely important to choose stock that does not have white face in their genetics. White face will remove all yellow pigment and eliminate the yellow cheek patch entirely. A split to white face could still be a visual yellow face, but mixing these genes together is not recommended. It also is not recommended to mix the three types.
Dominant yellow face is reported to be the first truly dominant mutation. A cockatiel with two dominant yellow face genes would produce 100% visual yellow cheek patch babies. These babies only need to have one dominant yellow face gene to have a yellow cheek patch! A cockatiel with one dominant yellow face gene bred to a cockatiel with none will produce 50% yellow cheek patch babies. Once again this variety should not be crossed with white face.
Pastel is sometimes referred to as dominant pastel since it is complimentary to white face. Pastel is not dominant over ANY other color mutations. Pastel is an autosomal mutation that occupies the same space or "rung" on the genetic ladder as the white face gene. Each rung on the ladder has two halves. Each half can hold one gene. This particular half rung can hold one normal gene, or one white face gene, or one pastel gene. The opposing half can also hold one of these three genes. One complete rung can only hold a total of two genes.
Visual Pastel occurs when a cockatiel has either two pastel genes OR if it has one white face gene and one pastel gene. A cockatiel with only one pastel gene but no white face gene would still have an orange cheek patch. This phenomenon is called "complimentary" since these genes "work together". The white face gene replaces the normal dominant "orange cheek patch gene" on one ;half of the rung. This allows the otherwise recessive pastel gene to do its magic on the other half. ;In this case it is recommended to breed pastel to white face to give 50% pastel and 50% white face babies. Pastels can also be bred together to get 75% pastels.