16/02/2026
🦜🧬An Introduction To Budgie (and most other parrot) Genetics🧬🦜
There are hundreds of mutations in captive budgies today so there can be so much variation. In budgies there are four main mutation types;
Dominant; A bird can carry one or two copies of the gene but both heterozygous (carries one copy of the gene) and homozygous (carries two copies of the gene), look identical, the only example of this in budgies as far as I’m aware is green and potentially Easley clear bodies (ECB’s) but there aren’t any images available of homozygous ECB’s online. If a bird is heterozygous for a dominant gene is paired to a bird that does not carry the gene approximately 50% of the offspring will be heterozygous and 50% will not carry or express the gene. If a heterozygous bird is paired to another heterozygous bird 50% of the offspring will be heterozygous, 25% homozygous and 25% will not carry the gene. If a heterozygous bird is paired to a homozygous bird 50% of the offspring will be heterozygous and 50% homozygous. If a homozygous bird is paired to another homozygous bird 100% of the offspring will be homozygous. And finally, if a homozygous bird is paired to a bird that does not carry the gene 100% of the offspring with be heterozygous. This is because a homozygous bird will pass the gene to 100% of its offspring and a heterozygous bird will pass the gene to 50% of its offspring.
Incomplete Dominant; Very similar to standard dominant genes but there is a visual difference between heterozygous (carries one copy of the gene) and homozygous (carries two copies of the gene) birds. Some examples of these are spangle, violet, dominant pied and dark factors. Inheritance works the exact same as in the paragraph about dominant genes above.
Autosomal Recessives; Autosomal recessive genes are genes that require two genes (homozygous) to be visually expressed, heterozygous birds look visually normal and cannot be told apart from birds that do not carry the gene, heterozygous birds are called splits/carriers. Some examples of autosomal recessive genes are: blue, recessive pied, dilute, clearwing and all the fallow mutations. Inheritance of these genes are the same again but remember that the only birds that are homozygous will visually express the gene and that heterozygous and birds that do not carry the gene are visually identical.
Sex-Linked Recessive; Sex-linked recessive genes are carried on bird's s*x chromosomes ZW in hens and ZZ in c**ks, specifically on the Z chromosome. This means that hens only need one copy of the gene to visually express the gene and c**k birds need two copies of the gene (one on each Z chromosome), this also means that:
Hens cannot be carriers for s*x-linked genes; they are either visual or don’t carry the gene at all
C***s can be visual or carriers for s*x linked mutations
Some examples of s*x-linked recessive genes in budgies are: opaline, cinnamon, Texas clear body (TCB) and the ino gene. The inheritance for these genes is very different from all the previous ones due to them being located on s*x chromosomes are requiring different numbers of the gene depending on the s*x. To start with the easiest if you pair a visual c**k bird to a visual hen you will get 100% percent visual offspring in both s*xes. If you pair a split c**k to a visual hen, you will get 50% visual offspring in both s*xes and the non-visual c**k birds will be carriers. If you pair a visual c**k bird to a normal female 100% of the female offspring will be visual and 100% of the male offspring will be carriers. If you pair a split c**k to a normal hen, 50% of the female offspring will be visual, the other 50% of the female offspring will be normals, 50% of the male offspring will be carriers and the other 50% will not carry or express the gene. Finally, if you pair a visual hen to a normal c**k bird 100% of the female offspring will be normals and 100% of the male offspring will be carriers.
