Why do you refer to some color mutations as "split". It would be interesting for someone to explain the terminology for the different colors.

The green color of many parrots is composed of blue and yellow, one of which (I -think- it's the blue) is the result of the structure of the feather, and the other, presumably the yellow if I'm remembering correctly, is the actual -color- of the feather. Combined, they make the bird look green. Since a different gene is responsible for each, any green species of parrot could produce individuals that are missing the yellow gene, resulting in a blue bird, and others that are missing the blue gene, resulting in a yellow bird. Cinnamons have a weaker "blue" gene, producing a lighter and yellower green bird. With me?

Cockatiels, on the other hand, get their grey color from the pigment melanin in their feathers (the same stuff that turns your skin dark when you tan), and the yellow and orange are feather color. If a bird has less melanin, it is a lighter color, which in cockatiels is a cinnamon. A tiel that has no melanin but still has its feather color is a lutino, a white and yellow bird with orange cheek patches. A whiteface tiel has melanin, but no colored feathers, resulting in a totally grey and white bird.

So, if you're following me, what's a whiteface lutino? A bird that has no color AND no melanin, which would be an albino, right? In point of fact that's one way to breed albino tiels - cross lutinos with whitefaces. Pieds have melanin missing in patches, and pearls are lacking melanin in the ends of the affected feathers, in case you were wondering.

Ok, now to explain the word "split." Almost all color mutations in our pet birds are recessive, meaning that if you mate a green (dominant normal) bird to a yellow (recessive mutation) bird, all of their babies will LOOK green, or normal. To make it easier to understand, pretend that each bird has two "genes" for color, either of which can be G (green) or y (yellow), and it gets one from each parent. A normal bird will have two genes for green, or GG. A yellow bird MUST have two genes for yellow, or yy (I'll explain why in a minute). So, If you mate a Green bird to a yellow bird, the babies all get one Green and one yellow, resulting in a gene makeup of Gy.

So, why do they all look green? Well, that's why the terms dominant and recessive - if both are present, the dominant or "normal" color is the one that will be expressed visually. The green bird whose genotype is "Gy" is called "split" to yellow, meaning it carries the yellow color gene but doesn't show it. Ok, so what happens if we breed two (unrelated, of course) of these splits together? The babies will come up GG, Gy, and yy! Statistically, about half of them will be "splits" (Gy), and about one fourth of them will be yellow (yy). So, a breeder who wants to get into yellows or blues and doesn't have a lot of money might buy some (cheaper) split-to-color birds, and get 25% babies of the desired color that she can keep and later breed. Does it all make sense now? :-)

Actually, it gets MUCH more complicated than this because some mutations are sex-linked recessive, for example lutino in cockatiels. A male cockatiel can be a lutino or be split to lutino, but a female can only BE lutino or not, she can't be split to it. (I think in birds a female is xy and a male is yy, and the sex-linked color is carried on the y gene, or something like that.) The fun part of that is, if a male split to lutino gives the lutino gene to a female baby, she will be a visual lutino! So, that's how I got a lutino baby out of two grey cockatiels, and how I determined that my male must be "split" to lutino and the baby must be a hen.

In cockatiels, whiteface and pied are "straight" recessives, and pearl, cinnamon, lutino, and albino are sex-linked. So, what do you get when you cross a male whiteface cinnamon pearl split pied with a cinnamon pied split whiteface and pearl? ANSWER: No eggs, since they're both males - a female cockatiel can't be split to pearl! I know, I know - mean trick question!