Friday, January 4, 2013

Bourke Coloration, A Question and Answer

White faced, pink-eyed Rosy Bourkes; opaline fallow.
QUESTION:
Hello,

I have baby Bourkes this year and really enjoy them so much. I have had Bourkes for about 3 years and not had any babies til I got another pair, which have been wonderful parents. The first clutch gave me 2 beautiful normals and this present clutch gave me 4 babies that are now 2 wks old. One of them has pink eyes and looks like a pink belly and some yellow on its wings and lots of blue. They are still very young to tell, but I am wondering what it may look like. The father is a normal and the mother is a Rosy Bourke. It will be fun to find out as it grows. If you have any insight please let me know what I might be seeing.
Just love your website and have sent you emails previously about my Splendid parakeet. He is still alone, but maybe someday he will have a friend. He is such a sweetheart
Thank you for your time.

I'd call this mixed coloration a "pied" Bourke.
ANSWER:
Congratulations! And thank you for the compliment on my website.
Since color in Bourkes is sex-linked, a baby Bourke's color will come from the parent of the opposite sex. So, your Normal babies should be hens since their father is the Normal. Any Rosies will be males since their color comes through the mother.
An exception to this is the heterozygous or homozygous characteristic. I had a pair of Normal Bourkes who always produced male Normals and Rosy hens. Why, you ask? Because the male was heterozygous (his father was a Rosy and his mother a Normal). He was split to Rosy.
A Bourke that's heterozygous carries a gene for the other color, not just one color. Make sense? I still struggle with this concept.


A mated pair of Normal Bourkes. Male in back has same
colors, but brighter. Also a tiny blue ridge above cere.
So, unless a Normal male is heterozygous—and yours is not going to be since you've been getting Normal offspring from him—all your Rosies will be male because their mother is a Rosy and their father is a Normal. Your pink-eyed baby will be male.

I wish you luck with all four of them. I seem to lose more of my pink-eyed offspring as that genetic trait tends to be less strong than the dark-eyed birds. Yellow lutino's are also less strong. Healthiest of all are usually the normal, wild color. The breeding toward rosy or pink is beautiful, but less robust than their wild-colored, brown/rose/blue, ancestors.
As for the color of your one baby with pink eyes and yellow and blue feathers, there are lots of possibilities. People have been producing what they call “rainbow” Bourkes with lots of mixtures. It would be interesting to see a photo of yours when it’s fully feathered out.

This photo was sent to me. Breeder says it is a "rainbow" Bourke.

A mixed clutch of Normals and Rosies. Both parents are
Normals, but father is heterozygous and throws Rosy hens.

I’m no geneticist and asked my husband if he could explain this any better than I did. He added this:
“As with all living things, the pink color is due to genetics. We — birds and humans — have pairs of genes. We received one from our mother and one from our father. A geneticist would call an individual possessing two of the same genes for a particular trait homozygous. Homo comes from the Greek homos, meaning same. Similarly, they would refer to an individual possessing different genes for a particular trait as heterozygous…coming from the Greek h├ęteros, meaning different.”

2011 siblings. Younger baby has red eyes.

Photo by Jill Warnick of her mixed clutch.
Lutino's are all hens since their father is a Lutino.
Mother is a Normal Bourke, so Normal baby is male.

January 18, 2013:
My small sampling doesn't give an accurate picture of all that is genetically possible. If you've come across this post, please also read a more accurate and easy to understand update on Bourke Coloration in the following link:


For more details on avian genetics, here’s another link to a website that I found diffcult to follow, but others might appreciate: aviangenetics.com

Peace and Blessings.

1 comment:

neversink7 said...

Young opalines (what is usually commonly called rosey in the USA and rosa in Europe) may have a mixture of various colors but often molt out to be the usual pink colored rosey. Sometime the multi-coloration stays so people call them "rainbow", but the fundamental mutation is still opaline. Selective breeding have produced opalines with more green or blue coloration rather than the usual pink.