The Greygreen or ‘Olive’ Cockatiel

I have seen two references to a novel colour form of the Cockatiel on the Web which is referred to variously as the ‘Olive’, the ‘Emerald’, or the ‘Olive Emerald’. No doubt the Cockatiel community was initially quite excited about this variety, which apparently has a definite greenish appearance and might well have initially raised the hope of a resurrection of the dormant blue producing cloudy layer or spongy zone. (See remarks in article The Parblue Puzzle, Part 1 on these pages.)

Neither of the pages located give much information about the fundamental nature of the new variety. There is an article Cockatiel Mutation Feature Showcase, by Linda S. Rubin, a well known writer on Cockatiel subjects, but this is only the first few paragraphs of a much longer article and contains little information we can interpret. All we really learn is that the new variety is apparently being produced in light, medium, and dark forms, and that some have a definite green appearance. We are not even given a fancy name to complain about!

The other site is Elsie's Cockatiel Mutations where the ‘Olive’ pages, for all their brevity with words, do give some useful information. We learn some details of the appearance of the new variety, that it was first bred by Margie Mason of the US, that its inheritance pattern is recessive, and that it seems to have been crossed with every other variety in sight and, not surprisingly therefore, appears in a number of different guises.

At neither site do we get even so much as an adequate description of the basic form of what has against all precedent been christened the ‘Olive’ by its early breeders. True, there are photographs, but at their small size and low screen resolution the information they impart is limited. However, they do seem to show that the greenish colouration is most evident on the head and rump areas. Besides this, the photograph of a developing chick on Elsie's page 2 shows an olive-yellow colouration quite clearly and that of the ‘Olive’-Whiteface composite gives a fair indication of the changes in melanin distribution and pattern. There is no mention or sign of blue colouration in the latter.

What we now need to know is what changes, if any, occur in the distribution and colour of yellow psittacin pigment. This should become evident when the ino factor is bred into this strain.

On the evidence so far I think we have to assume the greygreen coulouration comes about by an interaction between the melanin and psittacin pigments present in the feathers, in a way similar to that seen in other birds with a natural greygreen or olive colouration such as the European Greenfinch (Carduelis chloris) or, in the context of the parrot varieties, the Grey Green budgerigar. Whether this implies some change in the nature of the melanin in the feathers, as well as its distribution and pattern, remains to be investigated.

With the above in mind Peter Bergman has suggested that the variety would be better known as the Greygreen, rather than using the name ‘Olive’ which has its own special meaning in the field of psittacine genetics. Taking into account the natural genetic nature of the Cockatiel, this would certainly be almost in line with good naming practice.

In any event its seems that we are not yet going to see a Blue Cockatiel, nor one with such bright greens as most other parrots since there is no evidence that the cloudy layer has been reactivated.

The mention of light, medium, and dark forms of the variety can almost certainly be put down to the presence of composite varieties (i.e. varieties showing the effects of more than one mutant gene) due to indiscriminate breeding with birds possessing such factors as cinnamon, fallow, dilute (silver), etc.

If any reader has experience with this variety, and can provide further information, I shall be pleased to publish and attribute this.

Copyright: Clive Hesford, 1998