I sometimes get questions from folks new to breeding Cockatiels concerning what colours to expect. I'm putting this page up so I can help those people who wish to learn about basic colour mutations. Although this is simplified, some previous basic genetics knowledge would be an asset. If you have any questions, comments, additions, or suggested revisions, please see Contact Us.

There are two basic types of crosses I'll introduce you to:

1. sex-linked recessive (Lutino, Cinnamon, Pearl) with examples

2. autosomal recessive (Pied, Whiteface) with examples

(Recessive means that the colours we'll be using are dominated by the normal (Grey) colour of the Cockatiel.)

After I introduce you to both of these, we'll be able to take a look at some two colour combinations.

SEX-LINKED COLOURS

Sex-linked colours are found on the pair of chromosomes that also determine the sex of the baby bird.

In humans, the woman has two X sex chromosomes; she is XX. So, all her ova are a single X (one half of the genetic material). The man determines the sex of the baby because he is XY, and each of his sperm contain either an X or a Y sex chromosome. Each partner contibutes one sex chromosome, so a woman always donates an X, and the man donates either an X or a Y. If the man donates an X sperm, the baby is XX (a girl), and if he donates a Y sperm, the baby is an XY (a boy).

The very first thing you need to know to begin to understand avian genetics, is that in birds this is reversed. The female is XY and the male is XX.

The chromosomes are in pairs, with the X being full-length, and the Y being shorter:

A sex-linked colour is a colour whose gene is found only on the X sex chromosome. The most common sex-linked recessive colours in Cockatiels are Lutino, Cinnamon, and Pearl. To keep it simple, I'll use Lutino as the example in the following explanation, but please remember all these examples work for Cinnamon and Pearl as well.

In the male, there is a location (the blue band) on each of the X chromosomes for the Lutino gene, but in the female there is only one location on her single X chromosome. The short Y chromosome does not have a location for the colour gene:

This means the male can have normal genes at the location for Lutino on both X chromosomes and he would be a Grey:

MALE

NORMAL + NORMAL = NORMAL (NN)

or he could have an Normal on one and the recessive Lutino gene on the other. If he has one of each, then the Grey will dominate, and he'll appear Grey, but will be called "split for Lutino" because he carries the hidden Lutino gene:

NORMAL + LUTINO = NORMAL (SPLIT FOR LUTINO) (N/L)

If he has the Lutino gene on both X chromosomes, then he will be a Lutino:

LUTINO + LUTINO = LUTINO (LL)

The female only has one X chromosome, and the other is a Y. Think of the Y as a "nothing". It will neither help nor hinder what is on the X, because there is no corresponding location on it for a Lutino or Normal gene. If the female has a normal gene at the location for Lutino on her X, then she is a Grey:

FEMALE

NORMAL + Y = NORMAL (Ny)

If she has a Lutino gene on her X, then she is a Lutino. The female cannot be split for Lutino:

LUTINO + Y = LUTINO (Ly)

Please be aware that we are only talking about one colour at a time. In the above examples, Normal means normal only for Lutino, which is the colour factor being worked on. The bird may not necessarily be Normal for other colours. The colours are separate and are located on different genes (bands) on the X chromosome, so a bird could be Normal for one colour, and show another.

We'll take a look at some examples of birds with more than one colour later.

EXAMPLES OF SEX-LINKED COLOUR COMBINATIONS

Lutino means an absence of Grey. Popularly known as a "white" Cockatiel, Lutinos have orange cheeks and yellow in them; all that's missing is the Grey.

A Cinnamon has a soft beige colouring wherever there would normally be Grey.

A Pearl is speckled or spotted in the grey areas.

In the following examples, where Lutino is used, you can substitute Cinnamon and Pearl, because they are sex-linked colours too. All of the examples assume there is no other colour present other than Lutino.

Here are some sample pairings to give you an idea. To get started, we'll pair a normal grey male with a normal grey female. Use a lower-case "y" for the second gene on a female when doing a sex-linked cross:

Grey male x Grey female

NN x Ny

	N	N
N	NN	NN
y	Ny	Ny

The male is at the top of the table; the two blue N's. The female is at the left, represented by a blue N and a blue y. To get the results for the probability for potential offspring, combine the letters in each row and column. The offspring are in pink. There are two NN's, those are grey males, and there are two Ny's, those are grey females.

You can write the results:

50% Grey males (NN)
50% Grey females (Ny)

Please be aware that in this and the following examples, the percentages are only *probability* of each of the potential colours or sexes. Just like in human families, the actual results don't always match the probabilities exactly. But over a period of time, the results should approximate these percentages.

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Next, we'll put a Grey male, who is split for Lutino (he looks like a normal Grey), with a Grey female:

Grey split for Lutino male x Grey female

N/L x Ny

	N	L
N	NN	NL
y	Ny	Ly

When an N and an L occur together in the same box, always write the L second, because it is the recessive (not dominant) gene.

Here's the results:

25% Grey males (NN)
25% Grey split for Lutino males (N/L) (they look grey)
25% Grey females (Ny)
25% Lutino females (Ly)

Here is an example of where you can put two Grey birds together and get a Lutino baby. When this happens with any sex-linked colour, you know for certain that:

1. the male is split for that colour

2. the babies that show the colour are always female

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Try to solve the rest of these by making your own tables on a piece of paper before looking at the answers....

Now let's try a Lutino male with a normal Grey female:

Lutino male x Grey female

LL x Ny

	L	L
N	NL	NL
y	Ly	Ly

Results:

50% Grey split for Lutino males (N/L)

50% Lutino females (Ly)

This is so neat! When the male is Lutino, and the female is a normal Grey, *all* the Grey babies in the nest are males and *all* the Lutino babies are females. Guaranteed. You can sex them the day they hatch! The Lutino females will have pink bulges where their eyes will be, and the Grey males will have dark bulges.

Any time you have a male that is showing a sex-linked colour, and the female is not showing that colour, you will be able to tell the male and female offspring by their colour, even in immature plumage.
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Here's a Grey split for Lutino male and a Lutino female:

Normal Grey split for Lutino male x Lutino female

N/L x Ly

	N	L
L	NL	LL
y	Ny	Ly

Results:

25% Grey split for Lutino males (N/L)
25% Lutino males (LL)
25% Grey females (Ny)
25% Lutino females (Ly)

As you can see, half will be Lutinos (both males and females) and half will be Greys, with the males being split for Lutino. You won't be able to tell which sexes they are by looking at the colour.

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The last example is an easy one. Put a Lutino male with a Lutino female:

Lutino male x Lutino female

LL x Ly

	L	L
L	LL	LL
y	Ly	Ly

Results:

50% Lutino males (LL)

50% Lutino females (Ly)

AUTOSOMAL (non sex-linked) COLOURS

This is the second kind of cross, and it's actually easier to work out than sex-linked crosses. Here we are talking about the basic colours pied and whiteface. In these examples, I'll use Pied (P), but it will work for any recessive colour that is not sex-linked.

These colours are not found on the sex chromosomes, but on a different pair. These chromosomes are the same for both the male and the female, so we do not use the Y:

Here is an example of the chromosomal pairs for Pied or Whiteface in a Normal Grey male and female:

Both the male and the female can be split for Pied and Whiteface:

When both chromosomes carry the gene for Pied or Whiteface, the bird will show the colour:

EXAMPLES OF AUTOSOMAL COLOUR COMBINATIONS

Pied is a colouration where parts of the bird are white, sort of in patches. Some or all of the wing and tail feathers may be white, too.

Whiteface is the absence of yellow and orange colouration. A Cockatiel that is a whiteface has a white face with no orange cheek patch and no yellow in its face, crest, or anywhere else on its body. Whiteface chicks have white down, instead of the yellow down of a normal Grey chick.

Here's how to do these crosses. First we'll do a Grey male with a Grey female that is split for Pied:

 

Normal Grey male x Grey split for Pied female

NN x N/P

	N	N
N	NN	NN
P	NP	NP

 

Again, remember that we write the "N" first because the Normal (Grey) is dominant. The results are:

50% Greys (NN)

50% Greys, split for Pied (N/P)

Wait a minute. What happened to males and females? Because these are autosomal colours, there is no difference between the male and female method of inheritance. You can only figure out the percentages of colour *in both sexes*.

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Next:

Pied male x Grey split for Pied female:

PP x N/P

Results:

50% Greys split for Pied (N/P)

50% Pied (PP)

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Try to work this one out on your own first:

Grey split for Pied male x Grey split for Pied female

N/P x N/P

	N	P
N	NN	NP
P	NP	PP

Results:

25% Greys (NN)

50% Greys split for Pied (N/P)

25% Pieds (PP)

Again, these percentages are the same for both sexes. For example, the "25% Pieds" offspring can be both males and females.

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And lastly:

Pied male x Pied female

PP x PP

	P	P
P	PP	PP
P	PP	PP

Result:

100% Pied (PP)

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COMBINING TWO COLOURS (or more)

The most important thing to know when trying to figure out the probabilities on two or more colours is: you must do them separately! Different colours are located on different pairs of genes. If you try to put two colours on the same chart, it will be an absolute mess, and you'll get the wrong results, too. The best way to show you how to do it, is to work through a few examples. The results for each separate colour, and also the combination, will always add up to 100%.

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Let's start with a Pied male and a Cinnamon female. We're workng with two colours: Pied and Cinnamon. In order to figure it out correctly, do the one colour factor first, then do the other factor separately. Then you'll be able to see how to combine the results. I'll start with Cinnamon.

***This is very important. When we are speaking of Cinnamon, we are talking about the location on the sex chromosomes (the bands on the X's we pictured earlier) for Cinnamon. The female *is* a Cinnamon (Cy) but the male is *not* a Cinnamon (CC), or he would be a Cinnamon Pied. So for the Cinnamon factor, we have to say the male is a normal (NN). Forget that he is a Pied for now, we're just talking about Cinnamon, and he has no Cinnamon in him.***

Normal male x Cinnamon female

NN x Cy

	N	N
C	NC	NC
y	Ny	Ny

Results (for Cinnamon factor):

50% normal split for Cinnamon males (N/C)

50% normal females (Ny)

 

Now we'll do the Pied factor. The female is normal for Pied.

Pied male x Normal female

PP x NN

	P	P
N	NP	NP
N	NP	NP

Results (for Pied factor):

100% normal split for pied (N/P)

 

Now, combine the two results:

50% normal split for Cinnamon males (N/C)
50% normal females (Ny)
and
100% normal split for pied (N/P)

Since all of the offspring are split for Pied, we can say:

50% normal split for Cinnamon and Pied males (N/CP)

50% normal split for Pied females (Ny/P)

If you prefer, you can work out the combination on a chart. Results are in pink, and we'll use the ♂ symbol for the male, and the ♀ symbol for the female (instead of the "y"):

	50% N/C ♂	50% N ♀
100% N/P	50% N/CP ♂	50% N/P ♀

All the offspring will appear Grey, but you know all of the males will be split for Cinnamon and Pied, and the females will be split for Pied.

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Next, a Lutino split for Pearl male x normal Grey female. Lutino first:

LL x Ny

	L	L
N	NL	NL
y	Ly	Ly

50% Normal split for Lutino males (N/L)
50% Lutino females (Ly)

 

Now Pearl. We'll use S (think Spotted, Speckled) for Pearl so as not to confuse with P for Pied):

N/S x Ny

	N	S
N	NN	NS
y	Ny	Sy

25% Normal males (NN)
25% Normal split for Pearl males (N/S)
25% Normal females (Ny)
25% Pearl females (Sy)

 

Now combine to get:

25% Normal split for Lutino males (N/L)
25% Normal split for Lutino and Pearl males (N/LS)
25% Lutino females (Ly)
25% Lutino Pearl females (LSy) (white with yellow speckles, and appear more yellow than a Lutino.)


If you use a chart, since there are males and females in both the rows and columns, be careful to keep them separate:

	50% N/L ♂	50% L ♀
50% NN ♂	25% N/L ♂
50% N/S ♂	25% N/LS ♂
50% N ♀		25% L ♀
50% S ♀		25% LS ♀

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Next, a Cinnamon split for Whiteface male x Grey split for Whiteface female. Cinnamon first:

CC x Ny

	C	C
N	NC	NC
y	Cy	Cy

50% Normal split for Cinnamon males (N/C)
50% Cinnamon females (Cy)

 

Now do Whiteface:

NW x NW

	N	W
N	NN	NW
P	NW	WW

25% Normal (NN)
50% Normal split for Whiteface (N/W)
25% Whiteface (WW)

Now combine, and you get:

12.5% Normal split for Cinnamon males (N/C)
25% Normal split for Cinnamon and Whiteface males (N/CW)
12.5% Whiteface split for Cinnamon males (W/C)

12.5% Cinnamon females (Cy)
25% Cinnamon split for Whiteface females (Cy/W)
12.5% Cinnamon Whiteface females (CyW)

	50% N/C ♂	50% C ♀
25% N	12.5% N/C ♂	12.5% C ♀
50% N/W	25% N/CW ♂	25% C/W ♀
25% W	12.5% W/C ♂	12.5% CW ♀

The percentages for Whiteface are distributed to both sexes, because Whiteface is not sex-linked. Any babies that show the Cinnamon colouration will be females, and 1/8 of the offspring will be Cinnamon Whiteface females. Notice how the offspring percentages (in pink) total 100%.

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Next, a Cinnamon Pearl male x Pearl split for Pied female:

Cinnamon:

CC x Ny

	C	C
N	NC	NC
y	Cy	Cy

50% normal split for Cinnamon males (N/C)
50% Cinnamon females (Cy)

Pearl:

SS x Sy

	S	S
S	S	S
y	Sy	Sy

 

50% Pearl males (SS)
50% Pearl females (Sy)

Pied

NN x N/P

	N	N
N	NN	NN
P	NP	NP

50% normals (NN) (both sexes)
50% Pieds (N/P) (both sexes)

 

Combine:

50% normal split for Cinnamon males (N/C)
50% Cinnamon females (Cy) and

50% Pearl males (SS)
50% Pearl females (Sy) and

50% normals (NN)
50% split for Pied (N/P)

you get:

25% Pearl split for Cinnamon males (S/C)
25% Pearl split for Cinnamon and Pied males (S/CP)
25% Cinnamon Pearl females (CSy)
25% Cinnamon Pearl split for Pied female (CSy/P)

If using a chart, since we're doing three combinations, we need to use two charts. First do the Cinnamon and Pearl factors:

	50% N/C ♂	50% C ♀
50% S ♂	50% S/C ♂
50% S ♀		50% CS ♀

Now use the above results (in pink) as the top row on a new chart with the Pied factor:

	50% S/C ♂	50% CS ♀
50% NN	25% S/C ♂	25% CS ♀
50% N/P	25% S/CP ♂	25% CS/P ♀

 

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Grand Finale!

Whiteface split for Lutino male x Lutino split for Whiteface female:

Whiteface:

WW x NW 

	W	W
N	NW	NW
W	WW	WW

50% normal split for Whiteface (both sexes) (N/W)
50% Whiteface (both sexes) (WW)

Lutino:

N/L x Ly

	N	L
L	NL	LL
y	Ny	Ly

25% Normal split for Lutino males (N/L)
25% Lutino males (LL)
25% Normal females (Ny)
25% Lutino females (Ly)

Combine:

Across the top (in blue) are the Lutino factor results, down the left (in blue) are the Whiteface factor results. Potential combinations are in pink:

	25% N/L ♂	25% LL ♂	25% N ♀	25% L ♀
50% N/W	12.5% N/LW ♂	12.5% L/W ♂	12.5% N/W ♀	12.5% L/W ♀
50% WW	12.5% W/L ♂	12.5% LW ♂	12.5% W ♀	12.5% LW ♀

12.5% Normal split for Lutino and Whiteface males (N/LW)
12.5% Lutino split for Whiteface males (L/W)
12.5% Whiteface split for Lutino males (W/L)
12.5% Lutino Whiteface males (LW) this is a pure white, known as an Albino
12.5% Normal split for Whiteface females (Ny/W)
12.5% Lutino split for Whiteface females (Ly/W)
12.5% Whiteface females (NyW)
12.5% Lutino Whiteface females (LyW) this is a pure white, known as an Albino

So in this cross, you can expect the visual colours of Lutino (both sexes), Whiteface (both sexes), Normal grey (both sexes), and Albino (both sexes).

I have a friend who had a pair of Cockatiels in the above colouration. All we knew was that the male was a Whiteface and the female was Lutino. In their first clutch, they produced 3 Albinos and a Whiteface. (The odds of getting 3 Albinos in one clutch is only 1/64.) However, right away we know the male *had* to be split for Lutino, and the female *had* to be split for Whiteface. Can you figure out how we knew this?

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♂♀