by Ken Gray
Why? Well, most books on budgerigars convey the information, and
most fanciers believe, that a Blue is a mutation from the Green
whereby all the yellow has been lost leaving a blue body color
bird with a white head and mask; and a `Yellowface' is something
that can be added to any Blue or Grey bird by introducing a
dominate mutation in the form of a bird that already shows the
characteristic.
What then are the real facts? They are that there have been a
number of different mutations of the Light Green (what is known
as the `wild-type'), all affecting the body color, and therefore
creating a number of mutant varieties. The yellow of the green
bird is wholly or partly suppressed in certain areas and in
varying degrees. These are all mutations of the same pair of
genes and are actually alternatives, each producing a different
visual effect. As all genes must be in pairs, (one or other gene
of each pair being duplicated by each parent and passed on to
each chick), each mutant gene can be just one gene of the pair
(the other gene being `wild-type'), or doubled up by being
duplicated by being both genes of the pair, or paired with a
gene of alternative mutations. There are quite a number of
permutations.
In one case - the most well-known one - the whole of the yellow
of the 'wild-type' Light Green has been suppressed and we do
have a blue body colored bird with a white head and mask and
with no trace of yellow anywhere in its body or tail feathering.
That is what we, as a Fancy, tend to call a Blue, but is better
described as a Whiteface Blue. It is, of course, known to be a
recessive mutation, as any Green bird can be split for it. The
visually blue bird has two identical mutant genes; a Green/Blue
has only one, the other of the pair being the `wild-type'.
It was not the first mutation affecting the body or mask color
reported - there had been reports of a blue budgerigar with a
yellow face being in existence in 1881 - but it certainly was
the first mutation of this sort to be `fixed' and bred on a
regular basis.
Blue budgerigars with yellow head and mask did appear again -
this time in
One mutant variety, it was discovered, only showed the yellow
face when the character only existed in single factor - that is,
only one gene of the pair was for 'Yellowface', the other gene
of the pair being for 'ordinary' Blue produced both yellowfaced
and whitefaced young in the nest (approximately 50% of each over
a number of nests) it was conveniently labeled as a dominate
mutation. That is the mutation we usually see on the show bench
in the yellowface classes. It is known as Yellowface Blue Type
1, or preferably, Mutant 1, as the word 'type' has other
meanings.
It was discovered much later, and proved only after years of
experimentation, that when this mutant gene (Mutant 1) was
inherited in double factor the result was a whitefaced bird
indistinguishable from an 'ordinary' Blue (or grey). That bird
which was genetically double (which of course also had a white
face), produced 100% yellowfaced young. It would have to do so,
if you think about it, as the double factor 'Yellow face' parent
must pass on one or the other of its Yellowface Blue Mutant 1
genes, and we know that that mutation in single factor actually
shows a yellow face. The yellow face and blue body are the
product of the same mutation from the 'wild-type' Green; they
are not two separate mutations. We can, and do, have visually
Green birds, say Normal Light Greens, which are split for
Yellowface Blue Mutant 1.
So that is two varieties of the group - our 'ordinary'
(Whiteface) Blue and Yellowface Blue Mutant 1. Now to the third.
This we know as Yellowface Blue Mutant 2. When a chick has
inherited in single factor (ie, a mutant gene from just one
parent) it is of similar appearance in nest-feather to a chick
of Mutant 1 - yellow head and mask, blue body. At the first
moult, the yellow of the mask floods down over nearly all of the
body feathering, making the bird look more like a Green than a
bird of blue body color. THe true blue can usually be seen under
the lifted wings and near the vent. When the mutant gene is
inherited in double factor (ie, from both parent) this flooding
down of the yellow at the first moult does not happen to
anywhere near the same extent, the yellow being more restricted
to the head and tail with a yellow flush to the wings. Even so,
there is more yellow than seen on the Mutant 1 bird first
described, so that it cannot comply with the existing Yellowface
Blue color standard which is really for Mutant 1.
There is another similar mutation to Mutant 2 (or it might
actually be Mutant 2 plus a color modifying gene) which
reproduces to exactly the same pattern but has a richer, more
golden yellow head and mask. It has been known as Goldenface
Blue for as long as I can remember - at least as long back as
the 30's. As it did not conform to the Yellowfaced exhibition
standard, and was mostly confined to the composite variety known
as Goldenfaced Rainbows or to Goldenface Blue Recessive Pieds,
the exhibition breeder knew very little about it.
There is more interest shown now since it has been reintroduced
as 'Australian Yellowface'. It is the same, or a second
identical, mutation. That has been proved. I have Goldenface
birds from both sources. It can only be hoped that when
eventually a proper Color Standard for the mutation is devised,
that its original name of Goldenface Blue will also be
standardized. I should add that a green bird can be split for
Yellowface Blue Mutant 2 or for Goldenface(`Australian
Yellowface') Blue, or for Mutant 1 or for Whiteface Blue. It
can, of course, only be split for one of them, or it would not
visually be a Green. So you can see that the 'wild-type' Light
Green, and the various mutations from it affecting the yellow
body color, all form a group of alternatives, the 'wild-type'
Green being the only dominate, and all the other being
recessive. They are a group of what are called 'multiple
allelomorph', and as earlier stated can provide a number of
permutations of color of body and mask feathering.
It is to be hoped that the Color Standard Committee will soon
include standards for all the Yellowface and Goldenface Blue
varieties, so that they can be exhibited with the others of
their own kind. It will mean a complete revision of the existing
standards.
