I have decided in this article to simplify the Budgie color variations also arguably known as mutations.
I'll try as much as I can not to be scientific in an effort of making it clear to everyone. Also I will not go into genetics, I will only explain the effect of genes on the budgies.

The basic color form of the budgie is the wild type green. That bird doesn't have any of the mutated genes that alter its color. This bird is called "Light green Budgie".
Now when mutated genes are added to the basic light green budgie, we get all the array of colors our Budgies exhibit.
The first gene that modifies a wild type budgie is called the "dark factor", this gene darkens the shade of the body color and can be present in one or two "doses".
A light green budgie that got one dark factor from either of his parents is turned into a darker shade of green and is no longer called "light green" but rather "green" budgie, and this is where everything starts. In the same way, a light green budgie that gets two dark factors is turned into an olive shade of green and is known as the "Olive green" budgie.
Light green, green and olive greens are color variations of the budgie.

The green color of budgies is not caused by green pigmenting; it is caused by a blue coloring mixed with a yellow ground color. As we all know, blue and yellow mix into green.
The blue budgie is one that, due to mutated genes, has lost the ability to produce the yellow ground color and this budgie is left with the blue.
Green budgies have a green body, a yellow head and black and yellow wings, when they get two blue genes, they loose the yellow and thus, the green body becomes blue, the yellow head becomes white and the yellow and black wings become white and black wings and you get your blue budgie.
Having 2 blue genes doesn't mean that this budgie can't have other mutated genes, in fact they can have a lot of other color varying genes at the same time. Let's take the simplest example, the dark factor.
An otherwise light green budgie with two blue genes would turn into a beautiful turquoise and the budgie is called "Sky" blue. This budgie that already has the mutated blue gene could have inherited one dark factor too and therefore he would have been a darker shade of blue known as "cobalt" blue.
Had he inherited two dark factors, he would have turned into an even darker blue, almost grayish known as the "mauve" budgie. As you can see, the budgie can have a multitude of mutated genes at the same time.
Sky blue, cobalt and mauve are color variations of the budgie.

A number of other genes can be added to the basic green and blue budgies, some modify the wing pattern (opaline, spangle), some change the wing color (greywing), some genes reduce the intensity of the yellow ground color (yellowfaces) and others have an overall effect like the Ino gene that removes all coloring except the ground color and we're left with either a white or a yellow bird.

Nothing prevents a budgie from having more than one modified gene at the same time. This is how we get the color variations. Green spangle opaline, yellowface whitewing, mauve spangle cinnamon recessive pied etc…. basically all combinations are possible.

So next time you see a strikingly beautiful budgie, remember, under all that, there is a light green wild type budgie with mutated color genes.

Thank you pass

take care

Our expert Pass,

Thank you very much, I am sure it benefits everyone as it is simple to understand.

Keep on the great working.