Birth of color and pigment types in cockatiels
What creates a color?
Different colors are born depending on the produced color pigment and the structure of the feather.
Melanin – Dark colors. Melanine also effects the feet, talons, beak and the eyes. For example a lutino cockatiel has red eyes because of the lack of melanine: because there are no pigment, you can see the veins turning the eye red! Melanin types can be separated in eumelanin and phaeomelanin. Eumelanin affects the dark shades from black to brown and grey – and also their mixes. Phaeomelanin is behind the rusty, red and yellowish tones. Parrots can produce mostly eumelanin and on that account, as this website uses the word melanin it refers always to eumelanin. Lutino (ino) is a mutation in which all the eumelanin pigments are lacking.
Psittacine – A pigment type creating the red and yellow color plus all their mixes and tones. Psittacine is an unique pigment type, met only among parrots – and also the name psittacin refers to parrots, scientifically named as Psittacidae). Psittacine affects only in the feathers and won’t change anything in feet, eyes or beak. Whiteface is a color mutation in which all the psittacine pigments are lacking.
Color pigment placement inside the feather
Through-cut of a cinnamon female’s feather
To better understand how the colors are shown one must take a very close look to the feather, inside the feather barbs – those little barbs holding the feather together. If a feather bard was cut through in half it would remind sort of a donut, a tree branch or straw from which you can separate the following parts:
1) Cortex: The outer ring, containing the psittacine pigments.
2) Spongy Zone: The middle layer. This part co-operates with the sunlight, causing blue and violet colors.
3) Medulla: The center, containg all te black and brown eumelanin pigments, surrounded by the little holes called vacuoles.
And now follows the important part: Cockatiels are completely lacking the spongy zone! They don’t have that structure at all in their feathers. That’s why cockatiels can’t produce blue or violet colors. And that’s why I have added number two in the through-cut inside the brackets.
Pigment change types
Change in melanine pigment, affecting only the feathers. As the word “dilute” tells, this pigment type dilutes the dark colors. Some parrot species have the true dilute mutation but also many of those colors named differently are actually variations of dilute. The naming refers more to the color type and the way that the melanine behaves than just one particulas color mutation. The true dilute of cockatiels is known also as pastel silver or east-coast silver.
Change in melanine pigment, affecting feathers, eyes and skin. This phenomenon is caused by the albinistic factors preventing the tyrosinase enzyme formation, needed in melanine production. Albinistic genes are often recessive and can cause color getting lighter in many different levels. The true albino is a bird in which the albinism has caused the complete lack of melanine so that there is none dark colors left at all. Most obvious example of an albinistic color is the ino gene with its alleles, causing for example lutino and the sibling color platinum. But also cinnamon is actually an albinistic color. In all these colors, the melanine reduction reaches feathers, skin and eyes.
Change of pigment, causing the lack of dark color either completely or partially. Leucism can have affect on all pigments (and this fact also separates it from albinism). It can affect also locally in certain places. A great example of a leucistic color mutation in cockatiels is the recessive pied. In this color, mostly the melanine is affected, causing it to remove partially so that the bird has unsymmetrical dark spots.
Change in melanine pigment, causing the melanine to incresing. Melanism affects only to feathers and you could think about it sort of as an opposite of dilution. In dilution the melanine is reduces, in melanism it’s increased. There has not yet been met a melanistic color in cockatiels.