Blue Fischer's lovebirds are one of the most recognised mutations in the hobby — white face, blue body, no orange-red mask. But what most breeders quickly discover is that "Blue" is not a single mutation. There are two distinct Blue alleles — Blue 1 (B1) and Blue 2 (B2) — and when a bird carries one of each, the result is a third, separate phenotype called Parblue. Understanding this distinction is essential before planning any Blue breeding programme.
Blue 1 (B1): Homozygous B1/B1 — classic blue bird, white face, no psittacofulvin
Blue 2 (B2): Homozygous B2/B2 — similar appearance to B1, subtle differences
Parblue: Heterozygous B1/B2 — intermediate phenotype, blue-green body with pale face. Neither fully blue nor green.
I've sourced Blue Series birds from both Indonesia and the Philippines, and the Indonesian lines consistently carry higher rates of co-present Aqua within two generations I reliably see B2 offspring emerge without needing separate Aqua stock investment, which adds real market value to the line without extra cost.
What Does the Blue Mutation Do?
In wild-type Fischer's lovebirds, the green body colour comes from two pigment systems working together: eumelanin (which produces the structural blue-green background) and psittacofulvins (which overlay yellow on top, producing green when combined with the blue structure). The orange-red face comes from high concentrations of psittacofulvins in the head feathers.
The Blue mutation disrupts the psittacofulvin production pathway, eliminating the yellow-red pigment from the plumage entirely. The result: the structural blue-green colour is revealed without any yellow overlay. Body becomes blue-green to cobalt, and the face becomes white or very pale because there is no orange-red psittacofulvin left to produce the mask colour.
Blue 1 (B1)
Homozygous for the B1 allele. Classic Blue Fischer's — white face, cobalt-blue to blue-green body. Fully eliminates psittacofulvin.
Genotype: B1/B1Blue 2 (B2)
Homozygous for the B2 allele. Very similar to B1 visually. B2 and B1 birds look almost identical without genetic testing or breeding records.
Genotype: B2/B2Parblue
Carries one B1 and one B2 allele. Shows an intermediate phenotype — partial blue expression. Blue-green body, pale yellowish face. Visually distinct from pure Blue.
Genotype: B1/B2Why Does B1 × B2 Produce Parblue?
This is the question that confuses most breeders. If both B1 and B2 produce blue birds when homozygous, why does combining them produce something different?
The answer lies in how the two alleles interact. B1 and B2 are different mutations at the same gene locus — they affect the psittacofulvin pathway in slightly different ways. When a bird carries one copy of each (B1/B2), neither allele is fully dominant over the other. The result is a bird that shows partial psittacofulvin reduction — not zero (like pure Blue) and not full (like Green), but somewhere in between. This intermediate expression is Parblue.
This is different from how simple recessive mutations work. With a standard recessive mutation, a split (one copy) looks like wild type because one working copy of the gene is enough. But B1 and B2 are each slightly broken versions of the same gene — neither works fully, so a B1/B2 bird shows partial effect.
Parblue and Aqua both produce turquoise or blue-green birds, and they are frequently confused. They are completely different mutations at different gene loci. Parblue arises from combining B1 and B2 Blue alleles. Aqua (B1 or B2 of the Aqua locus) affects the blue psittacyanin pathway. A Parblue bird paired with another Parblue will NOT produce Aqua birds. You cannot convert between them through breeding.
Core Blue Pairings
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100%
Parblue (B1/B2)All chicks get one B1 from father, one B2 from mother
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25%
Blue 1 (B1/B1)Pure Blue 1 homozygous
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50%
Parblue (B1/B2)Intermediate phenotype
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25%
Blue 2 (B2/B2)Pure Blue 2 homozygous
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100%
Split Blue 1 (B1/+)All chicks carry one B1 — look green, breed blue
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25%
Blue 1 visual (B1/B1)Shows full blue phenotype
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50%
Split Blue 1 (B1/+)Looks green, carries B1
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25%
Normal non-carrierNo Blue gene
Calculate your Blue or Parblue pairing
Combine with Opaline, YF, Violet, and moreBlue vs Aqua: Key Differences
Because Parblue and Aqua look similar — both turquoise-ish, both departures from green — they are one of the most commonly confused mutations in the hobby. Here is the definitive comparison:
| Feature | Parblue (B1/B2) | Aqua (B1 or B2) |
|---|---|---|
| Gene locus | Blue locus (psittacofulvin pathway) | Aqua locus (separate gene) |
| Face mask | Pale / yellowish-white | Orange-red present but altered |
| Body colour | Blue-green, more blue-ish | Turquoise / sea-green |
| Produced by | B1 × B2 crossing | Aqua × Aqua pairings |
| Homo form | B1/B1 or B2/B2 = pure Blue | Aqua Homo = deeper turquoise |
| Can produce Aqua? | No — different gene | Yes, from Aqua × Aqua |
Identifying Blue Birds Visually
Pure Blue Fischer's lovebirds (B1/B1 or B2/B2) have these characteristics:
- Face: White or very pale, completely lacking orange-red psittacofulvin
- Body: Blue to cobalt, depending on lighting and feather condition
- Eyes: Normal dark brown — Blue does not affect eye colour
- Feet: Normal grey — Blue does not affect foot colour
Parblue (B1/B2) birds show a clearly intermediate appearance — the face is pale but may have a slight yellowish tinge, and the body has a visible greenish-blue quality rather than the cleaner blue of homozygous birds.