Recent Update to the International Guidelines for Colour Mutations in Psittaciformes
1998 – Present
By Dirk Van den Abeele
Ornitho-Genetics VZW
online 1 april 2026
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In February 2026, the international guidelines governing the nomenclature of colour mutations in Psittaciformes (parakeets and parrots) were slightly revised. These are not major changes, but rather a refinement of the guidelines relating to the naming of combinations of alleles at the same gene locus.
Advances in our understanding of the interaction between alleles of a single gene indicate that, irrespective of the mode of inheritance, such alleles behave as semi-dominant in most cases. In semi-dominant (intermediate) inheritance, neither allele is fully dominant, resulting in an intermediate phenotype that differs from that of either parent.
In the past, different guidelines were applied to combinations involving dominant versus recessive alleles. Current insights show that this distinction is no longer necessary.
These guidelines are reviewed approximately every five years. During this process, input is also sought from technical committees and aviculturists. Although these guidelines primarily address the nomenclature of colour mutations in parakeets, they can, with a degree of flexibility, be readily applied to other bird species as well.
A Brief Historical Overview
The foundation for these guidelines was laid on Saturday, 21 March 1998. At the request of BVA-International, representatives of several federations were brought together in Serskamp: KAOB, KBOF, NBVV, PSC, and ANBVV. Initially, the objective was to establish uniform nomenclature within the Dutch-speaking avicultural community.
In 1999, I was contacted by Inte Onsman of MUTAVI, Research & Advice Group, with a request to collaborate within MUTAVI. Later, veterinarian Dr Terry Martin from Australia proposed the development of an international English-language terminology.
With the rise of the internet, international communication became much easier. This led, among other things, to the formation of the Genetics-Psittacine Group, a platform through which ideas and proposals were discussed with fanciers worldwide.
What initially appeared to be a straightforward task soon proved to be highly complex. A wide range of opinions and proposals had to be carefully considered. It quickly became clear that a solid and sustainable framework could only be established by taking into account:
- Existing terminology in aviculture and science
- The views of specialised study groups
- The genetic basis of each mutation
- Pigment formation
- Established scientific conventions
As the first international agreements began to take shape, support also had to be built within Belgium and the Netherlands. This was not without debate, but acceptance gradually increased step by step.
Over time, however, the Genetics-Psittacine Group became a victim of its own success. Discussions became increasingly difficult to manage. It was therefore decided to continue with a smaller working group and to place greater emphasis on scientific substantiation. Shortly afterwards, Dr Terry Martin withdrew from the project. The work was then continued by Ornitho-Genetics VZW and MUTAVI.
In recent years, the primary focus has been on scientific alignment. Several consultation meetings have been organised with researchers in order to refine the guidelines where necessary. Knowledge continues to evolve, and for that reason these guidelines are periodically reviewed and updated.
Purpose of the Guidelines
The purpose of these guidelines is to improve communication among fanciers by promoting the use of uniform names, conventions, and genetic symbols for colour mutations. In order to establish the broadest possible, stable, and scientifically sound foundation, many of these agreements are based on existing scientific literature.
The international guidelines are based on the following pillars:
- Agreements established by breeders in collaboration with Dr Terry Martin on the Genetics-Psittacine list (1997–2008)
- Consultation with scientists and alignment with existing scientific publications
- The guidelines of the ICZN (International Code of Zoological Nomenclature)
- Established genetic conventions regarding formulas and symbols
- As a provisional final pillar, guidelines were drawn up at the request of judges and various technical committees (TCs) regarding which colour combinations may be accepted on the show bench. These agreements were established in 2001 in consultation with judges in order to preserve the recognisability of phenotypes.
Important: these exhibition rules may differ between organisations. Each technical committee retains the right to allow exceptions within its own association.
Those wishing to consult the extended version, including guidelines on genetic formulas and taxonomy, can download it via the Downloads section at www.ogvzw.org.
Nomenclature Rules for Colour Mutations
- New mutations are always assigned English names.
- If a mutation type (based on pigment formation) has already been scientifically described in other species, the existing name is adopted, provided that it complies with the agreed conventions.
- Proper names and geographical names must not be used for new mutation names.
- In both Dutch and English, the base colour (green, blue, aqua, turquoise) is always placed last; for example: pastel green, meaning the pastel mutant in the green series.
- In Dutch, mutation names are written with a lowercase initial in running text: dominant pied, opaline, turquoise, etc., except at the beginning of a sentence or where normal capitalisation rules apply. This may vary from country to country and depends largely on local grammatical conventions.
- These names should preferably be applicable across all species within a taxonomic order (e.g. all parakeet species, all finches, etc.).
- No separate name is now assigned to a phenotype resulting from the combination of two or more different mutations, nor to SF or DF phenotypes of a dominant gene. One historical exception remains: lutino and albino. Our preference had been to use ino green and ino blue, in line with other mutation combinations. Although everyone agreed that these terms are not incorrect, the preference remained for lutino and albino, as these are universally recognised terms.
- Crossing-over combinations are designated by naming the base mutants with a hyphen (-) between them, e.g. cinnamon-ino or opaline-ino. This is easy to remember, as the term crossing-over itself also contains a hyphen.
- Combinations resulting from multiple alleles are indicated by writing both base mutant names together, for example PastelIno. Capital letters are used to indicate the start of each mutant name. PastelIno is derived from pastel and ino.
- In combinations involving allelic forms and crossing-overs, the name of the least mutated (least reduced) allele, relative to the wild type, is written first.
- The abbreviations SF and DF are used to indicate single-factor and double-factor forms in dominant mutations. (In Dutch, EF and DF are also used, but SF/DF is preferred in English.)
- Since two types of ino are recognised — a sex-linked recessive form and an autosomal recessive form — these are designated as NSL (non-sex-linked) ino for the autosomal recessive form and SL (sex-linked) ino for the sex-linked recessive form.
- For sex-linked dominant mutations, the designations SL SF and SL DF are used.
- Dark factors are indicated with a capital D: D green (one dark factor), DD green (two dark factors). This D refers to the genetic symbol of the mutant. A major advantage of this system is that it can be applied consistently across the green series, blue series, and any other base colour series.
- A (temporary or otherwise) incorrect name for a colour mutation is placed between asterisks (*).
Accepted Mutation Combinations
These recommendations were formulated at the request of judges in order to preserve the recognisability of the mutations present in Psittaciformes. They can be summarised as follows:
- Combinations of multiple eumelanin mutations are discouraged.
- Combinations of multiple psittacine mutations are discouraged.
- Only the opaline mutation is accepted in combination with either a eumelanin mutation or a psittacine mutation.
- Combinations of alleles of the same gene should be avoided as much as possible.
- In selective forms, the wild-type phenotype should be preserved as much as possible.
These simple rules are intended to ensure that each mutation remains readily recognisable, both to fanciers and to judges. As noted above, technical committees may still permit exceptions within their own show schedules or schedules of requirements.
Keep up the good work!!
Dirk Van den Abeele