Mutations of the Swift parakeet

(Lathamus discolor)

by Dirk Van den Abeele

Quite recently I was contacted by Geert Vankeirsbilck of Belgium about the Swift parakeet. He told me that there are some mutations of this Australian parakeet which he felt had been given names that did not fit with the reality. There are two mutations; one which carries the name pastel, and another called grey green or olive green. He also mentioned the existence of the red-bellied swift parakeet, but said that in his opinion these were a selective form of birds with many red spots on the belly rather than true mutants.

The goal of Geert is to gather accurate information about these mutations. I have no personal experience of breeding with the Swift parakeet, but I do have experience with genetics and feather structure of parakeets in association with Mutavi; where Inte Onsman and I examine the mutations of Lovebirds. So the statements which follow are based on my theoretical knowledge. To verify these statements we will study the feather structure of the swift parakeet, although results are not expected for a few months. This research project will be financed by Geert himself. The purpose of this article is to make a start in getting the people who breed these birds thinking on similar lines. All societies can later publish the results of this research if they wish.

To start, I contacted Mr.Terry Martin in Australia to ask if any mutations of these birds are known in their home country of Australia. The answer was negative. One of the reasons that there are not many breeders of those birds in Australia is probably because the birds live there in the wild. An enquiry from Mutavi and other foreign research centres confirms that no research has been done on the feather structure of these birds. This means that there is much work for us to do.

To obtain an insight into what these mutation are it is of great importance that we seriously examine the wild form first.

Description of the species in the wild

The beak and cere are horn coloured.

The eye has a golden-brown iris with black pupil.

The feet are flesh coloured with dark toenails.

Above the beak there is a red patch on the forehead which is brighter red in the male than in the female. This patch is the same breadth as the base of the beak and broadens out towards the top and is approximately 4mm high. Bordering on this red forehead patch is a cobalt blue crown with a diameter of 1cm. The sides of the lower mandible are bordered, as is the red throat patch, with a narrow yellow band. These yellow feathers extend up to the red forehead patch and to approximately 2mm in front of the eye. The green feathers on the cheek have a bluish shine.

The mantle, back and breast are green. Wing coverts are mainly green but with bordeaux-red overlaid with cobalt-violet coloured feathers at the top of the bend of the wing continuing to the primary feathers. The primaries have a fine yellow-greenish outer edge. On the back of the wing-coverts along the back feathers there is a small red patch sometimes surrounded by a narrow yellow border. The rump and upper tail coverts are green. Outer short tail feathers are black with a blue outer edge. The two central tail-feathers are bordeaux-red with a blackish tip. Wing coverts are red and the vent feathers are also red in the male, but more greenish in the female.

When the wings are spread, the blue feathers on the bend of the wing are formed by the central primary wing coverts. These feathers are cobalt overlaid with violet and black towards the outer edge and are not visible when the wings are closed. The shorter primaries are black with a greenish outer edge.

The presence of blue feathers indicates that the feathers are of the structural type. But, in fact, the wild bird does not have any sky blue feathering (only cobalt and violet) and, because the overall gloss to the green feathers has a violet tinge, I suspect that that the spongy zone has a violet interference, instead of the normal blue interference that we find in most birds. In other words, a possible blue structure with violet reflective qualities. But I again reiterate that this is only my opinion!

The two mutations will be discussed next. Readers belonging to the Parrot Society UK may wish to consult the beautiful pictures in the book The Swift parakeet, by Cyril Laubscher; a Special edition published and distributed to members in 1999.

Mutation 1 (‘Pastel’)

According to the literature this mutation has its origins in 1982 and is an autosomal recessive. The birds are born with red eyes which later on become dark brown. At first sight the contrast between iris and pupil is non-existent. A minimal contrast becomes visible however when looking closely. The blue feathers are less brilliant or duller than those of the wild type. Green body colour is more green yellowish, with the most bleaching on the front, and he nails are light grey. The flight feathers are look more grey-brown; not the deep black we see in the wild form. Red feathers appear unchanged.

The mutation is commonly called pastel, but sometimes also cinnamon or fallow. It is clear that this is a melanin thinning (diluting) mutation. I have an impression that this is not a discoloration towards brown but more a dilution to deep grey. The fact that this is an autosomal recessive mutation excludes the name cinnamon. Cinnamon is a mutation of the X chromosome and is sex linked recessive. Fallows are autosomal recessive and typically have red eyes. Since this is not the case here, more research is needed. In my opinion it is possible that it is an allele of the a-locus (the gene that codes for recessive ino, albinism) and that Fallow is the best name to use for the moment. To be sure we need further investigations by Mutavi.

Mutation 2 (‘Olive’ or ‘Dark green’)

This mutation appeared a few years ago somewhere in the Benelux and is said to inherit as a semi-dominant over normal wild coloured birds. On first sight it has the appearance of an olive green bird. We all know that the Olive green bird means a light green bird with two dark factors. This dark factor makes the spongy zone in the feathers becomes smaller, so we get Dark green and Olive green (one or two dark factors). In blue feathers that gives us the colour Skyblue (without a dark factor), Cobalt (with one dark factor) and Mauve (with two dark factors). Although the general body colour is olive green coloured, if we take a closer look at the blue feathers, we can see that these are not mutated to mauve (which happens in blue birds with two dark factors) but to a kind of dull cobalt.

Due to the fact that there is no specific intermediate form (Dark Green) and that the blue feathers are more dull coloured and do not change to mauve (as in birds with two dark factors) we can, in my opinion, exclude the existence of a dark factor and thus the name Olive green is incorrect.

Sometimes the name Grey Green is used for this morph. In a dominant Grey bird the barbs have neither spongy zone nor clearly distinguishable vacuoles. So birds without yellow psittacin in the cortex (blue series birds) show a grey colour. When yellow psittacin is present (green series birds) the Grey Green variety shows. However the blue feather fields in this mutation remain blue and, since that is the case, we can also rule out a grey factor and the name Grey Green.

So what is this mutation?

We suspect it is a mutation for the time being called Misty.

So far this autosomal dominant mutation is only known in Agapornis nigrigenis and also causes a dull, slightly bleached bird. In this species the single factor bird shows only a minimal deviation from the wild type. The difference shows more clearly in a double factor specimen. What happens in the feather of this phenotype we do not as yet know and research is still going on. The BVA pays the expenses and the results will be passed on to the Technical Committees of all Dutch and Belgian Societies. The intention, of course, is to esestablish uniform nomenclature within the lovebird world. This is something that can only be advised strongly for all other psittacine species.

With these few notes, we hope to reach breeders of Swift parakeets in other Societies and to strive for uniformity in naming these and other mutations.

© Dirk Van den Abeele

My thanks to Dirk for permission to feature this article on two varieties of the Swift parakeet which are not yet widely available. Dirk’s personal Webpages are at:

Agapornis Page

You will also find much of interest at the Belgian Lovebird Society (of which Dirk is the Chairman) Webpages:

Belgian Lovebird Society

Anyone wishing to contact Geert should go to the following Email address:

Vankeirsbilck.Geert@pi.be

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