When they have grey, dark, or violet factors especially, it can cause their beak and cere to be darker even black in some places from excess melanin or pigmint. The effect is usually the most noticible around the center and outside edges of the cere making it darker, and causing a black color to the beak.
By the time they go through their first moult these pigments usually have lightned, but it can confuse some on the true sex of their baby, thinking they have a boy because of the darker color, when it is really a girl by the true color of the cere itself
Male- Grey green.
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Female- Violet.
