How every result
is verified

The sources, in order of authority

1. Ornitho-Genetics VZW, the organisation of Belgian aviculturist and ornithologist Dirk Van den Abeele: its mutation list for Agapornis dated 17 August 2025 and the MutaBase mutation database.

2. The Lovebird Compendium by Dirk Van den Abeele (2016), the most comprehensive scientific reference on lovebird genetics.

When a newer Ornitho-Genetics VZW document differs from the 2016 book, the newer document wins. Example: the calculator models Yellow Face as its own autosomal recessive gene, the orange face gene, in line with the 2025 list, and our Yellow Face guide notes that the naming is still being settled.

The genetics rules the calculator applies

• Mendelian inheritance per gene. Each parent passes one allele of every gene, and a bird carries at most two alleles of the same gene.
• Sex-linked genes sit on the Z chromosome. Cocks are ZZ and hens are ZW, so a hen can never be split for Opaline, Cinnamon, Pallid or Pale. Results for sex-linked pairings are shown separately for sons and daughters.
• Shared genes are handled as one locus. Blue 1, Blue 2 and Aqua are alleles of one gene, which is why Blue 1 × Blue 2 gives Parblue. Ino, DEC and Pastel are alleles of another, giving the compounds DEC // Ino, Pastel // Ino and Pastel // DEC.
• Dominant and incomplete dominant are kept apart. Single and double factor Slaty or Dominant Pied look the same, so zygosity comes from the breeding record. Euwing and Misty show a visible difference between single and double factor.
• One notation everywhere. A single slash (/) means a confirmed split. A double slash (//) means a possible split or an allelic compound. See what a split lovebird is.

What we refuse to invent

The calculator never creates a phenotype, gene symbol or trade name that Ornitho-Genetics VZW has not published. If a combination has no documented appearance, it is not given a name.

• Sapphire is not modelled. Ornitho-Genetics VZW describes it as a crossover chromosome carrying two blue alleles, and its research is still open. See our Sapphire guide.
• Mottle is not modelled because its inheritance is multifactorial and cannot be predicted as a percentage.
• Violet and Dark Factor are explained in our guides but are not part of the calculator, and Faded is not modelled.
• Other species are not mixed in. The calculator is built for Fischer's lovebirds only; peach-faced lovebirds, for example, carry a sex-linked Ino that Fischer's do not.

How we test it

Every change is tested in a real browser before release, by entering pairings into the live calculator and reading the results it shows. Reference pairings must match the published ratios exactly, including all five sex-linked recessive patterns (for example, a visual Opaline cock × normal hen gives split sons and visual daughters), the dominant single and double factor patterns, and all five Greywing patterns.

Results are also compared with the breeding records of KinBird Aviary, so predictions are checked against chicks in the nest, not only against theory.

Limits you should know

• Percentages are probabilities. A clutch of four to six eggs can differ from the ratio; the numbers hold across many clutches.
• Splits cannot be seen. A result is only as accurate as the genotype you enter. If you are unsure, use // Split or the combined blue options so every possibility is shown.
• Fischer's lovebirds only. Results do not apply to other Agapornis species.

Corrections

When a newer Ornitho-Genetics VZW publication changes a rule, we update the calculator, the guides and this page together. If you think a result is wrong, message KinBird Aviary on Facebook with the pairing link and we will check it against the sources above.