lovemyfinch wrote:
Quick Q...what is the difference between a RTB and a YTB, besides the colour of course...is there a reason for this.

Yellow tipped indicates the bird is genetically orange head..
Red tipped just means the bird is carrying (at least) one red head gene. A red/orange bird will still have a red tipped beak - always; but an orange head bird will NEVER have a red tipped beak.
The process of being orange head eliminates the birds' ability to produce the carotene associated with the red color.
And this goes for the color we see expressed through the beak tip, as well.
Because she is not carrying a red head gene (which is still required to actually produce the orange color in the feathers - the pigments follow similar metabolic pathways), but a black head one, she can not visually produce the orange color in the feathers - but it still shows through in the beak, telling us that she is genetically an Orange head, but can't express it due to possessing the sex linked BH gene instead of red.
Confusing enough?
