FINCHforum

Any one know how the genetics for the fawn mutation works in shaft tails? The reason I am asking is my pair of shaft tails is a normal male and a fawn hen. I was wondering what I could expect from the babies. I was told that my male shaft tail might POSSIBLY be split to a white or isabela(spelling?) color. I was wondering if any one would have any info on how things might play out. I am not real good with genetics but I am trying to learn.

Fawn is sex linked recessive so a fawn hen (paired to a normal cock) will donate her single fawn gene to all of her baby boys, but because it is recessive and only one copy of the gene is present, the boys will not appear fawn. They will be split for fawn, however. Apparently these are 'visual splits' meaning they will show some characteristic that shows they are carrying the fawn gene.

White and isabel are autosomal recessive. If your male is carrying a copy of the white (or isabel) gene, he can pass this single copy on to some of his offspring (regardless of their sex). Those chicks who receive the gene will then be split for white (or isabel), as well. Not all chicks will get the gene, and it won't be possible, typically, to tell which birds have it and which do not just by looking at them.

I don't mean to interrupt, but that was a fabulous reply, Crystal. Seems like on every complicated technical question, you're right there with the answer every time. I guess that's why they pay you the big bucks around here, right?

Thanks Crystal, you said that all of the baby boys would be split to fawn, dos that mean that any hens born will be fawn or normal? If my male is split to white or Isabel could any of the babies possibly turn out that color or will they just be normal color and possibly carry the gene? Sorry if I am asking too many questions, just trying to learn.

It's not too many questions--genetics can be confusing.

Assuming that your cock is not split for fawn, all of the baby girls will be normal looking. Only IF your normal cock is split for fawn, is there a potential for some fawn daughters.

You will not get any white or isabel babies unless your hen is also split for white or isabel.

Basically all of your babies are probably going to look like normal shafttails, but the sons will carry a single copy of the fawn gene (making them "split" for fawn), and some of your babies (if your cock is split for white or isabel) will secretly carry the gene for white or isabel, depending on what they inherit from the dad. So you are correct in saying they will be normal color and possibly carrying the gene.

Eventually I'll get an article on my site up with illustrations to make all this a little easier to understand, similar to the gouldian genetics section.

And thanks, Steve. :) I don't know about big bucks, but I am really grateful to those who have made even small donations here and there to help cover the costs of hosting/maintaining the finch sites. None of that goes to paying me or my personal bills, though. You get me for free!

Thanks Crystal, I think I got it now.

Ok I have another question . Today I was watching my birds and noticed that my male shaft tail has a white tip on one of his tail feathers. Dose this mean anything or is it just a random occurrence?

bluefinch wrote:The reason I am asking is my pair of shaft tails is a normal male and a fawn hen.

hehe. I have a normal male and a fawn hen also! And, they are on eggs now (it has been about 6 days).

You will not get any white or isabel babies unless your hen is also split for white or isabel

i didnt think hens could be split for sexlinked mutations.
all shaft tail genetics are sex linked to m knowledge.

Ha! that’s funny vetbridge. I am glad to see yours are getting along nicely. My male has been giving me problems (you can see my post under general questions). Be shore to post some pictures once the babies hatch.

cooltom28 wrote: i didnt think hens could be split for sexlinked mutations.
all shaft tail genetics are sex linked to m knowledge.

You are correct that hens cannot be split for sex-linked traits. I had read that the White and Isabel mutations were autosomal recessive, however, and not sex-linked. I have not worked with these mutaitons personally though.

eFinch.com cites Isabel as being "autosomal recessive" on this page: http://www.efinch.com/species/shaft.htm.

The information about the white mutation being autosomal recessive comes from The Complete Book of Australian Finches by A. J. Mobbs.

I also have normal cock and fawn hen..but the problem is that they threw the chick out of the nest..im hand feeding them any tips?

There's an article about handfeeding at the Finch Information Center, and I think there is another one at www.ladygouldianfinch.com. I have been reading recently on another forum about people using the little application tool that comes with plastic leg bands to feed babies. They pick up some formula in the trough of the tool, and then let the babies suck or eat it off the tool, preventing aspiration. These people are also not feeding as often as has been advised in the past. However, they are talking about handfeeding babies that have just been given to Societies to foster, to get them thru the first few days, and then the Societies are taking over.

Hilary has a thread under Breeding about the Blue-Capped Cordon Bleus she is handfeeding, and she is using this band tool method.