The burning question on my mind this morning is what causes the blue color in the cere of adult male budgies? Budgies don't have blue pigment (at least not in the feathers) and it doesn't seem likely that the cere would have the kind of structure that makes melanin look like blue (which is what happens in the feathers). I'm guessing that the tan color of adult female ceres is caused by melanin under the influence of hormones but I don't know that for sure. I want to look this up later today, but if somebody already knows the answer please go ahead and tell me.

Be very interesting to know...
I've looked cant find out tho....
The top part of Bryni's cere looks blue.

I can ask on TalkBudgies for you. I generally don't like to go over there since I'm kind of shot down for being more of a tiel lover (and I'm not quite sure how they managed to figure that out) but I can do that if you want me to.

I found at least part of an answer. The scientific paper at http://www.plosone.org/article/info%3Ad ... 86849-g004 says the blue is a structural color and it's related to testosterone. I don't know the mechanics of exactly how it works so I'm not sure why certain mutations like ino and recessive pied don't develop the standard blue color, but I would guess that melanin is involved somehow. These mutations remove or reduce melanin, and I had previously guessed that melanin might be involved in the brown cere color that hens have when they're in breeding condition. So it seems reasonable so far.

I saw numerous websites saying that male budgies with testicular cancer or certain other diseases could develop a brown cere like a hen because they stop producing testosterone. Hens often have a pale blue or white cere when they're not in breeding condition and develop the brown cere when they're ready to breed. So male and/or female sex hormones definitely play a part in cere color.

I've been thinking about joining Talk Budgies myself to learn more about the species. It's OK if they're not super friendly to tiel people, I'm tough enough to deal with it lol.

I knew hormones were a play. If you want more confusion, Beck is a recessive pied with the typical pink cere, but he now has blue marks on it too. But even through the technical talk, I still think I'll go with my gut that baby number 2 is a cock.

Oh and I'm asking my dad Sunday night, hope it works out. For baby number 2!