Gouldian hen decides sex of chicks?

[MariusStegmann]

I read up on sexing gouldians and came across an article of studies that they did on Gouldians that points to the fact that the hen can determine the sex of her offspring. They found that they pair a hen with a cock with a different colour head than the hen, about 75 % of the offspring are cocks. If both birds in the pairing has the same colour heads, the ratio of hens / cocks are about 50/50. Is this really the case? I am now asking the experienced gouldian breeders?

[finchandlovebird]

Interesting; I'll be anxious to hear the answers to this question. Two pair of the six Gouldian pairs I have paired up right now have different colored heads.
I would also wonder if a "black head" whose head is white because he's not showing black, paired with a black headed hen counts as same or different color head?

[MariusStegmann]

The study was done by Dr Sarah Pryke. She is a fellow South African. She took 100 black headed and 100 red headed gouldians hens and mated them up with opposite colour cock. They also dyed the heads of cocks with a different colour which fooled the hen in changing the ratio of cocks versus hens. Apparently there is an incompatibility between red and black heads that results in a high mortality rate in the hens out of a red / black head pairing. The hen then changes the ratio of cocks because the cocks has a lower mortality rate. I wonder if this happens with the domesticated gouldian stock or only with Australian wild gouldians? If so, is it true with yellow heads as well?

[debbie276]

Sarah Pryke has several articles out there that are interesting:
http://sarahpryke.com/?page_id=11

Personally I have never found this mixing color heads to be true in my flock, I usually get very close to 50/50 whether the colors are mixed or not. Interestingly if I let the pair pick their own mates they almost always pick the same color head though.

[MariusStegmann]

I saw those. I find it interesting that when they covered the right eye of gouldians, they can't select a mate.

[finchandlovebird]

The replies to this went into my "Junk" folder; I guess 'cause it has the word "sex" in the title. Glad I found it in my junk

[MariusStegmann]

Dolly, I guess we don't have to worry about having pairs with mixed heads. I looks like the problem only occurs with the wild stock,

[kyubi]

I also remember I read something about the amount of UVB also have something to do with the sex ? Is it true ?or UVA ?

[MariusStegmann]

I have no idea. UVA ages us and UVB burns us. No idea what it does to birds, except they see different colours than what we see. Where males and females are concerned they can see at first glance what the sex is.

[debbie276]

Here is a good article about the different wavelengths of light and their importance to birds.
http://www.naturallighting.com/cart/sto ... sc_page=56

UVB is the short wavelength ultraviolet that causes sunburn and Vitamin D
UVA is the long wavelength ultraviolet that you get from a black light and can change the sex ratio of chicks.