Gouldiandave
@debbie276
(Not sure why only the first mention works; I've seen other posters successfully use several mentions)
This is actually quite an interesting topic, with implications far more significant than blaze colour/intensity.
Dr Sarah Pryke and her team at the Australian National University have undertaken a
wealth of very important reseach on Gouldians, and have quantified the significant negative outcomes of breeding Gouldians with mismatched head colour. They include:
- Increased stress levels in the hens of mismatched pairs (as indicated by the level of corticosterone in blood samples), with a resulting health cost to the hen;
- Latency to breed (mis-matched pairs tend to pair later in the breeding cycle);
- Latency to lay eggs (after pairing, mis-matched pairs tend to lay their first egg later);
- Most importantly, genetic inferiority of the resulting offspring, resulting in high offspring mortality (on average >30%, and for females >40% mortality);
- Highly skewed sex ratio of offspring (from memory, >70% males, because male offspring have much higher survivability).
The above results are for wild populations, so the most interesting question for me is whether these results are reflected in captive-bred Gouldians. This is one of my current research projects so I'll be accurately recording the sex ratios and mortality of my clutches over future breeding cycles.
As a general rule, given the above research, I would suggest avoiding pairings with mis-matched head colour.
You may have already viewed this ABC TV short documentary on Gouldian mismatched pairings:
http://www.abc.net.au/catalyst/stories/2589683.htm
"Different head colours are genetically incompatible and can’t breed successfully. If this (black-headed) female mates with a red-headed male, her children will pay the price. Many of her chicks will die, and her daughters will do particularly badly – only one in five will survive. But to compensate, the female has evolved an amazing defence. If forced to mate with a mismatch, she’ll produce chicks that are nearly all male, which have a much higher survival rate."
References:
"Constrained mate choice in social monogamy and the stress of having an unattractive partner", Simon C. Griffith, Sarah R. Pryke1 and William A. Buttemer (2011).
"POSTZYGOTIC GENETIC INCOMPATIBILITY BETWEEN SYMPATRIC COLOR MORPHS", Sarah R. Pryke and Simon C. Griffith (2008)
"Experimental evidence that maternal corticosterone
controls adaptive offspring sex ratios", Sarah R. Pryke, Lee A. Rollins, Simon C. Griffith, and William A. Buttemer (2013)