Category Archives: Algemeen

Violet factor in Forpus coelestis???

After we published our article in which we discussed the possible presence or absence of a violet factor in Forpus coelestis in the magazine of the Dutch Forpus Society, we received a telephone call from two enthusiasts stating that based on the breeding results of their birds, the so-called violet factor is most probably a dark factor. Unfortunately, we did not receive any data on their breeding outcomes.

A month later we published that same article in AOB Belgium and now we received breeding results from two fanciers, one from Spain and one from Belgium, which indicated that the violet factor in their Forpus coelestis is actually a dark factor.

So, till now,  we only have evidence for the presence of a dark  factor in Forpus coelestis.

FAQ: If blue1 and blue 2 are alleles …

FAQ: if blue1 and blue2 are alleles of the same gene, is it possible that each allele (blue1 or blue2) has its own specific alleles?

I am afraid not. That is why I mentioned in my article of April 2019  and I quote: “As mentioned before it is generally assumed that both genes, both blue type1 and blue type2, are located on the bl-locus. Yet there are some indications that we might be dealing with epistatic genes.”

Besides that we don’t know yet how the different genes, that affect the production of psittacofulvins, interact towards each others. This is still poorly understood.

So again: the only way to find an answer on these questions starts by DNA analyses and believe me, we are working on it


What about psittacofulvins in blue2 Agapornis personatus and Agapornis fischeri?

Blue Agapornis fischeri and Agapornis personatus are considered not producing any psittacofulvins (psittacines) in the feathers. However, we cannot ignore the fact that there are breeders who argue that their – pure bred – blue2 birds sometimes show traces of psittacofulvins in their feathers (to be clear, blue2 not in combination with *sapphire*).
Others are 100% sure and state that even in budgerigars [Melopsittacus undulatus] and ring-necked parakeets [Psittacula krameri], blue (2 ???) birds always contain psittacofulvins remains in their feathers.

If we consider the possible genetic causes behind this mutation, then we cannot completely exclude this possibility. So, we believe it is time to try to find a clear answer and not to continue to rely on assumptions. There fore, we have collected feathers from (100% pure bred) blue2 Agapornis fischeri and Agapornis personatus.
We will scan them with the Raman technology and if there are any psittacofulvins in the feathers, then we must be able to trace them. So hopefully time will tell.

FAQ: can food affect tyrosinase activity?

FAQ: can food affect tyrosinase activity?

I received this question from several canary breeders. They wonder if you can use specific foods or other vitamins to boost the tyrosinase activity in feathers. (They are trying to breed complete black canaries)

I was not 100% sure about this, so I contacted a few researchers and they all had the same answer: “As far as I know, food does not affect tyrosinase activity”.

Mechanisms behind mosaic canaries

A recent study, published in Science, shows that carotenoid-based sexual dichromatism in mosaic canaries, a hybrid phenotype that arises in offspring of the red siskin (Spinus cucullatus) and canaries (Serinus canaria), is controlled by the gene that encodes the carotenoid-cleaving enzyme b-carotene oxygenase 2 (BCO2). These results suggest that differences in ornamental coloration between sexes can evolve through simple molecular mechanisms controlled by genes and not always due to sexual selection for ornamentation and mate choice.

Gazda, Ma?gorzata A., Pedro M. Araújo, Ricardo J. Lopes, Matthew B. Toomey, Pedro Andrade, Sandra Afonso, Cristiana Marques, Luís Nunes, Paulo Pereira, Sandra Trigo, Geoffrey E. Hill, Joseph C. Corbo, en Miguel Carneiro. 2020. ‘A Genetic Mechanism for Sexual Dichromatism in Birds’. Science 368(6496):1270–74.

Een recent onderzoek, gepubliceerd in Science, toont aan dat op carotenoïden gebaseerd seksueel dichromatisme (verschil tussen man e pop) in mozaïekkanaries, een hybride fenotype dat ontstaat bij nakomelingen van de kapoetsensijs (Spinus cucullatus) en kanaries (Serinus canaria), wordt aangestuurd door het gen dat het carotenoïde afbrekend enzym b-caroteen oxygenase 2 (BCO2) codeert. Deze resultaten suggereren dat verschillen in kleur tussen geslachten kunnen evolueren door eenvoudige moleculaire mechanismen die door genen worden bestuurd en niet altijd door seksuele selectie en partnerkeuze.

Genus Forpus, een taxonomisch overzicht, beschikbaar als PDF

Onze artikelenreeks: Genus Forpus, een taxonomisch overzicht, hebben we op verzoek van diverse liefhebbers beschikbaar gesteld als PDF.

U kan deze downloaden via deze link

of via onze downloadpagina


FAQ: what is the tangerine gene / locus in parrots?

FAQ: what is the tangerine gene / locus in parrots?

To be honest, it does not exist. It was the Australian veterinary Dr. Terry Martin who used the term “tangerine locus”. He name the gene, from which he thought it was responsible for the production of the red psittacofulvins in the mask of Agapornis roseicollis, the tangerine locus [1, p. 230]. Jim Hayward used the name tangerine for the orange face mutation [1, p. 107].

Now we know that other genes (MuPKS) are involved for the production of psittacofulvins [2]  and there is no “tangerine gene” in parrots. BTW the name tangerine was given by MacArthur in 1934 to an orange coloured tomato and he talked about the tangerine mutation [3]. It had nothing to with birds.

[1]          T. Martin, A guide to color mutations & genetics in parrots, 1ste dr. ABK Publications, 2002.

[2]          T. F. Cooke e.a., ‘Genetic Mapping and Biochemical Basis of Yellow Feather Pigmentation in Budgerigars’, Cell, vol. 171, nr. 2, pp. 427-439.e21, okt. 2017, doi: 10.1016/j.cell.2017.08.016.

[3]          J. A. Jenkins en G. Mackinney, ‘Inheritance of carotenoid differences in the tomato hybrid yellow x tangerine’, Genetics, vol. 38, nr. 2, p. 107, 1953.

FAQ: Are cross sections the only way to determine colour mutations?

FAQ: Are cross sections of feathers the only way to determine colour mutations?

Absolutely not. Cross sections in combination with a light microscope give us only the basic information on what type of mutation we probably have:

  • Melanin mutations: Leucism? Albinism? Dilution?
  • Change of feathers structure / keratin layer?
  • Other pigmentation?
  • ……

For further research we need other, more specific tools.
Here is a list of recommended scientific instruments / methods needed to:

Impairment of mixed melanin-based pigmentation in parrots

Parrots and allies (Order Psittaciformes) have evolved an exclusive capacity to synthesize polyene pigments called psittacofulvins at feather follicles, which allows them to produce a striking diversity of pigmentation phenotypes. Melanins are polymers constituting the most abundant pigments in animals, and the sulphurated form (pheomelanin) produces colors that are similar to those produced by psittacofulvins. However, the differential contribution of these pigments to psittaciform phenotypic diversity has not been investigated. Given the color redundancy, and physiological limitations associated to pheomelanin synthesis, we hypothesized that the latter would be avoided by psittaciform birds. Here we test this by using Raman spectroscopy to identify pigments in feathers exhibiting colors suspicious of being produced by pheomelanin (i.e., dull red, yellow and grey- and green-brownish) in 26 species from the three main lineages of Psittaciformes. We detected the non-sulphurated melanin form (eumelanin) in black, grey and brown plumage patches, and psittacofulvins in red, yellow and green patches, but no evidence of pheomelanin. As natural melanins are assumed to be composed of eumelanin and pheomelanin in varying ratios, our results represent the first report of impairment of mixed melanin-based pigmentation in animals. Given that psittaciforms also avoid the uptake of circulating carotenoid pigments, these birds seem to have evolved a capacity to avoid functional redundancy between pigments, likely by regulating follicular gene expression. Ours study provides the first vibrational characterization of different psittacofulvin-based colors and thus helps to determine the relative polyene chain length in these pigments, which is related to their antireductant protection activity.

Neves, Ana Carolina de Oliveira, Ismael Galván, Dirk Van den Abeele. 2020. “Impairment of Mixed Melanin-Based Pigmentation in Parrots”. Journal of Experimental Biology.

On request: article Agapornis roseicollis: DM Jade

New mutation in Agapornis roseicollis: DM Jade
(Article published in 2017 / update 2018)

By Dirk Van den Abeele
Ornitho-Genetics VZW
MUTAVI, Research & Advice Group

It has been nearly ten years since Miriam Bisiacchi told me she had a deviating colour in a number of her Agapornis roseicollis. These birds had all been born with red eyes which became darker after a few days, but the main problem was that all these birds also contained the marbled factor. The consequence of course was that it was difficult to predict what this deviating factor actually does. Of course, we always recommended Miriam, as always, to try to breed this mutation in the green base type. That is the only way to determine what this mutation entails.

Asteriornis maastrichtensis

Amateur paleontologist Mr. Maarten van Dinther discovered in 2000, near the Dutch border in Belgium a fossil from probably one of the oldest – extinct – birds (known till now). Recent research at the University from Cambridge revealed that this bird lived in the Cretaceous period, that was 66.8–66.7 million years ago and they named it Asteriornis maastrichtensis. The bird was a mix of galliform (landfowl)-like and anseriform (waterfowl)-like features. Due to this, some name it the wonder chicken. Interesting to know is that this animal lived at the same period of Tyranosaurus rex.

The ‘wonderchicken’ fossil from Belgium reveals dawn of modern birds


Field, Daniel J., Juan Benito, Albert Chen, John WM Jagt, en Daniel T. Ksepka. 2020. “Late Cretaceous neornithine from Europe illuminates the origins of crown birds”. Nature 579(7799):397–401.

Archive articles

The last weeks we spend some time to our online archive ( and we were able to complete the list with my articles that have been published in:
• Alcedo Edizioni Srl
• AOB Belgium
• Arndt Verlag
• Avizandum South Africa,
• BVA-International
• BVP Belgium
• CDE France (list not complete)
• €uro-Parrot
• Kelsey Media UK
• Nederlandse ForpussenClub,
• Papousci – Czech parrot magazine
• Parkietenfederatie (list not complete)
• Parkieten Sociëteit
• Roma Press SA – Spain
• Onze Parkieten – The Netherlands
• KBOF – Belgium

We had a complete database with all these articles, but due a PC crash a few years ago, we lost the data from our articles published in:

ANBvV – The Netherlands
NBVV – The Netherlands
PSC – Parkieten speciaal club
Australian Bird Keeper
and an Hungarian magazine –  name unknow

Now we are trying to recover this data and to complete the list.

Hans Kater is coordinating this project, if you have these magazines in your library – or you are aware of other magazines – and you are willing to help us,  please contact Hans via