Dun Fallow in the Turquoise Parakeet

Autosomal recessive Melanin Symbol: df Red-eyed ~4 min read

Also written as: df

Quick summary

Dun Fallow is a red-eyed, autosomal recessive mutation in the "fallow family" that lightens black eumelanin to a greyish brown. It needs two copies to show. Be aware that whether the Turquoise Parakeet has a distinct mutation properly called "Dun Fallow" — as opposed to the European and Australian Fallow types — is not settled in the published literature. See the caution below before relying on this locus.

What is Dun Fallow?

Dun Fallow is logged in this calculator's reference data as an autosomal recessive melanin mutation with red eyes. It belongs to a well-documented family of "fallow-type" mutations found across many parrot species — bronze fallow, dun fallow, and ashen/pale fallow are the three most commonly named variants, and all share the same basic recipe: red eyes plus a lightened, warmer-toned melanin. Dun Fallow specifically shifts black eumelanin toward a greyish-brown rather than the warmer bronze tone of a true Bronze Fallow, or the near-grey tone of an Ashen Fallow.

Species attribution is unsettled: Campagne (2008) is internally inconsistent about Dun Fallow in this species. The genus-wide overview lists the mutation as occurring in both the Bourke's and the Turquoisine (p.75), but the Turquoisine chapter itself never names a Dun Fallow — it documents European Fallow and Australian Fallow Type 1 and Type 2 instead (pp.104–106), and the detailed Dun Fallow write-up appears under Bourke's Parrot (p.90). This locus is kept because breeders use the name, but if your bird came from a European or Australian line, check the Fallow guide — it may be one of those types rather than a true Dun Fallow.

An earlier version of this guide said Dun Fallow was also called "Isabel." That was incorrect for Neophema pulchella and has been removed. In this species the legacy name "Isabel" belongs to Faded alone. Elsewhere in the genus it has been used for Pallid and, historically, Ashen Fallow — but never for Dun Fallow.

How it works, in plain terms

Fallow-family mutations partially disable the enzymatic pathway that produces and darkens eumelanin, in both the feathers and the eyes. With less functional dark pigment in the iris and retina, the eye reads as red or plum rather than the normal dark brown/black — a useful field mark, since it's visible even in young or partially-feathered birds. In the feathers, the same reduced pigment softens black areas toward brown or grey depending on exactly which fallow-family mutation is involved.

Autosomal recessive inheritance, explained

Dun Fallow sits on an ordinary autosome, so cocks and hens inherit and can carry it identically. As a recessive trait, it takes two copies to show:

One copy (split) — the bird looks completely normal but can pass the mutation to offspring.
Two copies (visual) — the bird shows red eyes and the diluted, greyish-brown coloring.

Genotype → phenotype

Genotype	Appearance	Applies to
df⁺ / df⁺	Normal	Cocks & hens
df⁺ / df	Normal — split for Dun Fallow	Cocks & hens
df / df	Visual Dun Fallow (red-eyed)	Cocks & hens

Sources & honesty note

The inheritance type, symbol and category for Dun Fallow come from this calculator's own compiled reference library. The species-attribution caution above is drawn from Dr Alain Campagne, A Guide to Neophema and Neopsephotus Genera and Their Mutations (ABK Publications, 2008), pp. 75, 90 and 104–106, which does not consistently place this mutation in Neophema pulchella. The plain-language explanation of the fallow mutation family draws on general cross-species parrot and cockatiel genetics research; the precise Dun-Fallow-vs-Fallow-vs-Faded visual distinctions specific to Neophema pulchella have not been independently verified against species-specific photographs, so treat the color descriptions as a general guide. See the full references page for this project's other sources.