Creamface, pastelface, and whiteface are three recessive mutations that make up the parblue, or partial-blue, series. All three mutations affect the gene that controls the amount of yellow in a cockatiel’s plumage.
The whiteface mutation (pictured at the bottom) removes all yellows and reds from the plumage, giving affected birds a pure-white face. Combining fallow or olive with whiteface removes the characteristic yellow wash from these colors; whiteface fallows look like pale whiteface cinnamons, and whiteface olives lose their greenish tinge while retaining the slight scalloped pattern on their wing feathers.
Pastelface cockatiels (pictured on the left) have a reduced amount of yellow and red in their plumage, giving their cheek patches a pastel peach appearance.
Creamface (top right), which is a newer mutation and still quite rare, reduces the yellow and red pigments even more than pastelface, leaving just a hint of cream in the cheek patch, and an otherwise whitish face.