Introduction

by Wessel Louw van der Veen (Holland)

Before a name is given to a certain colour mutation it seems sensible to consider the colouring agents in the feathers first. Names based on tradition or for commercial reasons are hardly ever descriptive. The Dutch N.B.v.V. (Nederlandse Bond van Vogelliefhebbers, probably the largest world wide National Society with some 46.000 members) initiated research on feather structure in the early seventies. Based on this the society arrived at a set of names that can be used for both exotic and parrotlike birds. Afterwards standards of excellence for Lovebirds, Neophema's, Psephotus, etc. were written. Also the standards for Zebra finches, Gouldian finches or Bengalese made extensive use of these names. Those standards being scientifically based, it was already possible in the mid-seventies to predict that, for instance, dark factors might appear in Lovebirds. The major Belgian and French Societies have also accepted a greater part of these names, seeing the logic behind them. Below you will find the translation of one of the first articles published in the N.B.v.V. monthly “Onze Vogels” (“Our Birds”) about this subject.

Uniform Names

for Colour Mutants of Exotic and Parrot Species

In the feathers of most exotic and parrotlike birds the following pigments may be found:

1. melanin, which can be subdivided into:
   
   eumelanin (black or dark brown)
   phaeomelanin (reddish brown)
   
   
2. carotenoid or psittacin, which can be subdivided into:
   
   yellow carotenoid or psittacin
   red carotenoid or psittacin

In parrotlike birds the name psittacin is used to cover all colours from yellow to red since these pigments most probably cannot be influenced by the food given to the animals (as real carotenoids can).

Next to the above cited pigments the visible colour of the bird can be influenced by the internal structure of the barbs of the feather, the so-called blue structure in a normal (wild coloured) bird.

Black or dark brown melanin.

The feathers of most birds contain melanin. This presence shows itself as a black, grey, dark or light brown general body colour. When black melanin is found on a white or light yellow base, the body colour will – depending on the concentration of the melanin – vary from (light) grey (Zebra Finch, Cockatiel) to black (male of the Blackbird). When brown melanin is found on the same base colours the colour will vary from light brown to dark brown (Bourke‘s Parakeet).

* Reddish brown phaeomelanin

In a few birds only phaeomelanin is found (Bengalese, Chinese Painted Quail, Pyrrhuras, Canaries), however it usually combined with eumelanin. When a certain location contains (almost) exclusively phaeomelanin this feather field will show a reddish brown colour (cheek of male Zebra Finch, abdomen male Painted Quail). When both phaeo- and eumelanin are present the resulting colour will – depending on the concentration of each and the mixture of both – lean either towards reddish brown or to black or grey.

Blue structure

If as well as black eumelanin the barbs also posses the blue structure and this occurs on a white base we see a blue colour (the rump of an Agapornis roseicollis). When the blue structure is situated on a yellow base we see this colour as green (Gouldian Finch, Budgerigar, Neophemas, Lovebirds). The reddish brown phaeomelanin combined with the blue structure shows a purple colour (breast colour of a male Gouldian Finch).

Yellow and red carotenoids or psittacin

Yellow to red psittacin may be present in a pure form and also in a mixed one. Feather fields containing psittacin only therefore can have a colour from pale yellow via orange to bright red. When these feathers also contain melanin the colour will vary from a rusty brown or olive yellow (Agapornis Nigrigenis) to blackish brown or green. Should the concentration of melanin be very high it will mask the colour of the underlying psittacin (head of a Masked Lovebird).

Mutations

The following possibilities for mutation of the colouring agents exist:

Melanin

1. Pastel: A quantitative reduction (a decrease in quantity) of both eumelanin and phaeomelanin if both are present.
   
   In this mutation the aim should be a 50% reduction of the melanin. Where the body colour of the wild coloured bird is grey (Zebra Finch, Cockatiel) it will become a very clear grey. If the original body colour is black (male Blackbird) it will become grey. For this pastel mutation in these grey shades the name ‘Silver’ is often used erroneously.
   
   Where the wild colour of a bird species is reddish brown the pastel mutation will cause this to become a pale reddish brown. For a pastel brown the inept name ‘Cream’ is sometimes used.
   
   In birds with an originally green body colour (Gouldian Finch, Red Rumped Parakeets, Lovebirds) the pastel mutation causes this to become a yellowish green. This colour is often mistakenly called ‘Yellow’.
   
   
   
2. Suffused: Next to the above 50% reduction, a second one is known causing both phaeo- and eumelanin to reduce over 75% .
   
   The suffused mutation is known in the Diamond dove, the so-called ‘Brilliant’; the Peach Faced Lovebird, the so-called ‘Japanese Yellow’; and the ‘Yellow’ Budgerigar.
   
   
   
3. ** Isabel: A quantitive reduction of eumelanin.
   
   In this mutation there exists a heavy quantitive reduction of the eumelanin while the phaeomelanin, if present, remains untouched. Isabel phaeo will be recognised most easily in those birds where the body colour of the wild form is made up of both eumelanin and phaeomelanin. (Zebra Finch, Japanese Quail).
   
   
   
4. * Phaeo (Red Brown): A complete reduction of eumelanin.
   
   In this mutation the eumelanin is completely reduced while the phaeomelanin remains untouched. The phaeo mutant therefore will be recognisable only in those birds where both eumelanin and phaeomelanin are present in the feathers. Depending on the concentration of this phaeomelanin the final colour will become clear cream to reddish brown (Bengalese).
   
   
   
5. * Grey: A complete reduction of phaeomelanin.
   
   When phaeomelanin is reduced completely, while the eumelanin remains unaltered. The grey mutation will be recognisable only in birds normally possessing both eumelanin and phaeomelanin (Bengalese). Depending on the concentration of eumelanin the body colour will vary between light grey and dark grey.
   
   
   
6. Ino: A complete reduction of both eumelanin and phaeomelanin.
   
   In this mutation all melanin is reduced completely but the carotenoids or psittacins remain unaltered. The melanin in the eyes is reduced as well; this mutant usually has noticeably red eyes.
   
   When a bird possesses neither melanin nor carotenoid, or psittacin, a clear red-eyed white bird appears which is called an Albino; (Albino Masked Lovebird).
   
   When the bird possesses yellow or red carotenoid or psittacin only (and no melanin) the ino mutation causes a red-eyed yellow bird to appear which is called a Lutino. This yellow may be combined with red; (Lutino PF Lovebird, Lutino Greenfinch, Lutino Cockatiel).
   
   The ino mutations of those species possessing a small quantity of yellow pigment only are usually called Inos; (Sea Green Ino PF Lovebird).
   
   It does not matter whether an ino has yellow carotenoid or psittacin spread over its whole body or in certain feather fields only.
   
   
   
7. Pied: A complete reduction of both melanins (if both present) or of one melanin (if only one is present) per feather area. In this mutation melanin is reduced in a certain area. The carotenoid or psittacin remains unaltered. Pied birds should comply with the following demands:
   
   
   • the quantity of “piedness” should lie between 40–60%
   • the pied pattern should be symmetrical
   • the pied areas should be even coloured
   • feet, claws, and bill, should show one colour.
   
   By selective breeding it may be possible to create a fixed pattern (Banded Pied Budgerigar). To obtain the maximum of contrast, pied birds at an exhibition are only allowed where no quantitive melanin reduction has occurred. (i.e. no Pied Pastels). Of the pied mutation a dominant and a recessive form are known to exist. When both mutations are bred into one bird it is possible to breed an even coloured yellow or white bird (Dark-eyed Yellow or White).
   
   
   
8. Cinnamon or Brown: A qualitative reduction (incomplete oxidation) of the eumelanin.
   
   The eumelanin in this mutation has not oxidised completely. It is not black but of a brown colour. Birds not possessing the blue structure will get a body colour variable from clear brown to dark brown. Birds possessing the blue structure will have a very light brown suffusion on top of the green feathers.
   
   
   
9. Fallow: A further qualitative reduction makes the melanin granules even smaller then those of a cinnamon and turns them into a greyish brown colour.
   
   
   

Blue structure

Mutations causing a change in the internal structure of the barb:

10. Dark factor: The dark factor causes the diameter of the spongy zone to diminish. Skyblue will be seen as Cobalt, Light Green as Dark Green. When two dark factors are present Skyblue will turn into Mauve and Light Green into Olive Green.
    
    
11. Violet factor: The violet factor changes the diameter of the vacuoles of the spongy zone and causes a slightly different distribution of melanin in the barbs. Instead of blue light waves the violet ones are reflected. The violet structure shows at its best in a blue bird possessing one dark factor and one or two violet factors.
    
    
12. Grey: A change in the location of melanin at the centre of barbs possessing the blue structure. Due to a changed internal structure of the barb and a different location of the melanin at its centre the reflection of blue light waves is prevented. Green becomes grey-green and blue becomes grey (Grey Budgerigar, Grey-green Ringneck).
    
    
13. Opaline, Laced and Pearl: A relocation of melanin. In the opaline the melanin is relocated so that no black undulation remains visible in the hind neck and the mantle of the bird. The normal basic body colour now appears (Opaline Budgerigar).
    
    In the laced and the pearl mutation melanin is relocated in such a way that the edges of the feathers change in colour (Pearl or Lacewing Cockatiel).
    
    
    

Carotenoids or Psittacin

1. Sea Green: A quantitive reduction of carotenoid or psittacin. In this mutation the aim should be a reduction of carotenoid or psittacin of about 50% to 60%. This mutation will be visible best in birds originally having a green body (Gouldian Finch, Peachfaced Lovebird, Splendid Parakeet) The clear yellow or red areas will reduce to pale yellow and pink.
   
   
2. Blue: A complete reduction of carotenoid or psittacin. Both of these pigments are completely absent; the melanin however remains unchanged. Where in the wild form the body is green it now will change to blue. The formerly present carotenoid or psittacin being absent these areas change into a pure white (Blue Masked Lovebird, Blue Splendid).
   
   Should the wild colour be grey with a yellow suffusion (hen Cockatiel) then the body colour in the blue mutation will turn to clear grey (the barbs lack the blue structure) and the previous present yellow and red areas will become white (Whitefaced Cockatiel).
   
   
3. Yellow Billed: a local change of red carotenoid into yellow carotenoid. Here all red carotenoid has changed into yellow (Yellow Billed Diamond Sparrow) We often see that the general body colour too becomes slightly lighter, even when no carotenoids are present in that area (Yellow Billed Zebra Finch).
   
   
4. Orange: A change in the ratio of red and yellow psittacin in a certain feather field (Orange Faced Peach Faced). Psittacin can simultaneously be present in a barb in a yellow and a red form. The ratio of each colour determines the final colour. More red components will cause a red orange colour to appear; more yellow components will create a pale orange or even a yellow colour.
   
   

Translated from the Dutch by Wessel van der Veen.

Notes:

Remember that this report is intended to embrace all birds likely to be seen in aviculture and is not limited only to parrots. Those forms marked with an asterisk (*) are not found or recognised in the parrot family. It is also undesirable to use the term Isabel (**) since this implies the presence of pheaomelanin.

It is generally recognised that the feathers of parrots contain only eumelanin in its various forms and this alone is responsible for all the blacks, greys, browns, and fawns, which their feathers display. Many genes are involved in the production of eumelanin and mutations amongst these are responsible for the different colours seen. For our purposes we can ignore references to phaeomelanin.

The terms suffused (or dilute) and pastel are used only in connection with reduced amounts of melanin in the feathers. Black becomes various shades of grey; brown becomes various shades of fawn; green, because melanin is one of its components, becomes more yellow; and blue, for the same reason, becomes paler.

The Pieds are a complex set of varieties which can be categorised in many ways. Some, particularly in the budgerigar, naturally have a typical and regular pattern which is not the result of selective breeding. [See Is it a Pied? - What sort of Pied? for a discussion on this subject.]

A point to bear in mind is that these proposals were drawn up for the purposes of exhibition classification where an ‘Ideal’ is being pursued. In practice nature calls the shots and there is more natural variation than the percentages quoted allow for.

Clive Hesford: 25th March 2000

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