Written and published by Grant Donaldson (UK)
Before I get into the genetics and possibilities with this mutation I would first like to explain that I will be dealing with this mutation as two different types of Yellow Fischer. The two different types are shown below and are the Dilute Yellow and the Yellow Pastel.
Dilute Yellow Fischer’s Lovebird Yellow Pastel Fischer’s Lovebird
The yellow Fischer is the oldest of the mutations with the Fischer’s lovebird and has been around for over 25 years. It is my belief however that there are two distinct forms of the yellow Fischer that I would like to describe separately. The first is what I would call the original dilute yellow Fischer. It is a diluted bird with an approximately 50% reduction in melanin across its whole body. The second is what is referred to as the yellow pastel. This bird is a much more yellow bird, especially across the back and wings with the belly being a slightly greener colour, it experiences a 75-80% reduction in melanin.
So why should these two colours be treated as separate? It is true that the dilute form of the mutation can be progressively bred to increase the amount of yellow in the plumage though this takes considerable time. In most cases when attempting this the only noticeable benefit is producing superior birds in the sense that their body colour is more evenly distributed i.e. they are not patchy green and yellow.
The Dilute Yellow and Yellow Pastel Fischer are both typical recessive mutations. They both follow the same expected mode of genetic inheritance as follows:
Normal x Yellow = All Normals/Yellow
Normal x Normal/Yellow = Normals & Normals/Yellow
Normal/Yellow x Normal/Yellow = Normals, Normals/Yellow & Yellows
Normal/Yellow x Yellow = Normals/Yellow & Yellows
Yellow x Yellow = All Yellows
The above results are regardless of which parent carries the yellow gene.
When a dilute yellow is paired to a yellow pastel, the resulting offspring are either dilute yellow or yellow pastel. No intermediate phase is produced. I have proved this in two different nests with identical results. If a pure yellow breeding programme is attempted I would suggest trying it with yellow pastels to obtain good results the quickest. The expected crossings of Dilute Yellow to Yellow Pastel might be as follows:
Dilute Yellow x Yellow Pastel = Dilute Yellows and Yellow Pastels
It is this fact that both colours can be produced in the same nest by a pairing of each colour that leads to believe that they are separate mutations, though genetically equivalent of each other.
Yellow pastel and Dilute chicks both have orange down upon hatching. It has been written in various publications that upon hatching yellow chicks have a lighter coloured skin and eye colour when compared with a normal hatchling though I have not found this to be the case. At approximately the age of ten days chicks start to develop their secondary down. In yellow pastel chicks this is a whitish yellow colour. In dilute yellows this is yellow, occasionally with some greenish tinges to it. The eyes are of course black though the feet are considerably lighter in colour than their normal counterparts. Any dark striping to the beak is usually reduced if present at all. From the accompanying picture it can be seen that the difference in yellow pastel to dilute yellow is obvious from quite a young age.
It is of course possible to transfer both the yellow pastel and dilute yellow mutations through the other mutations available with the Fischer’s Lovebird though it is generally accepted that there is no point passing it through the edged mutation as the edged markings are lost on the resulting chicks.
Dilute blue and dilute darkfactor chicks are very popular though for some reason not as commonly bred as, for example, the same colours are within the Masked Lovebird. Dilute blue series birds are however available within the UK, usually of the dilute yellow variety. When a blue series yellow pastel is bred, care must be taken not for it to be confused with any of the Masked Lovebird mutations as the white forehead and grey crown will become very pale. Novice Lovebird breeders have in the past become confused between the two species/colour varieties and accidentally crossed the two. The resulting hybrid having features of both birds which are not desirable.
This dilute blue chick was bred from a cobalt/dilute yellow male to a dilute cobalt female. It shows the typical darker body colouring of the dilute yellow parental background. Had the bird been of the yellow pastel variety it would have been but an off-white colour over its back. From the same nest it should be expected that eventually dilute cobalt and also dilute mauve will be bred in varying percentages. Dilute blue chicks show a white to light grey secondary down colour.
To breed the dilute blue Fischer’s Lovebird you need to combine the dilute yellow or yellow pastel mutation with the blue mutation, which is also recessive. I personally prefer to use dilute yellows for breeding dilute blues as the range of colour available on the bird is greater. The expected crossings for combining the two might be as follows:
Dilute Yellow x Blue = All Normals/Blue/Dilute Yellow
The best way to start this breeding programme would be to run at least two pairs of dilute yellow to blue in tandem. This way the best young from both pairs can be retained to make unrelated pairs of the resulting double split normal offspring the following year, thus avoiding inbreeding.
Normal/Blue/Dilute Yellow x Normal/Blue/Dilute Yellow
= Normals, Normals/blue, Normals/dilute yellow, Normals/blue/dilute yellow, Blue, Blue/dilute yellow, Dilute yellow, Dilute yellow/blue & Dilute blue
It is obvious from the above results that the percentage of dilute blues will be quite small and that a lot genetically unknown birds will be produced as a by-product, but any breeding programme relies on the retaining of certain individuals to improve the programme each year, in this case the dilute blues and possibly the odd blue or dilute yellow. Once at least a couple of the desired dilute blues have been bred it is much easier to breed more and guarantee all by-products have a known genetic ability.
Dilute Blue Fischers Lovebird Dilute Cobalt Fischers Lovebird
It is interesting to note that when either of the types of dilute are paired with a Lutino that an intermediate phase of colour is produced. This is basically a very yellow bird. I have only known of dilute yellows that have been crossed to Lutinos, however, and the level of melanin reduction only brought the overall colour of the bird in line with that of the yellow pastel. It was this that led breeders to think that the first yellow pastels bred were actually dilute yellows split for Lutino which is not the case. Two yellow pastels paired together will not breed Lutinos.
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