Due to its prolification in captivity the Java Sparrow is now available in a number of mutations or colours. Mutations occur quite naturally both in the wild and in captive bred populations, the only difference being that in nature, unless beneficial to the birds survival, mutations rarely survive or propagate sufficiently to take hold. In captivity, due to humans' inate curiousity, these mutation are often actively encouraged and often coveted. Whilst keen to see an unmutated strain of Java Sparrows retained within aviculture, the JSSUK embraces any mutation which encourages active participation in the fancy, whilst being non-detrimental to any specimen's health.

There are a number of mutations readily available within the UK, whilst some rarer varieties may be more difficult to come by and restricted to individual or groups of specialist breeders, the vast majority are available often worldwide.

This page shows all of those mutations which are currently recognised by classification by the JSSUK. Many thanks to Tony Gladwin, Henk De Vos, Robbie Vallely, Steve Nesbitt, Rob Salem & Karl Duckworth for the photographs of the Java Sparrow mutations used on this page.

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Normal Colour

Name	Normal
AKA	Sometimes referred to as the Wild-type, Grey or even Native Colour.
Characteristics	The overall body colour is muted, whilst retaining all of the bird's phaeomelanin a certain amount of eumomelanin is lost in varying amounts giving its appearance a 'dilution' of colour.
Availability	At one point the wild-type was the only colour available in captivity but now this type is becoming endangered and pure specimens without mutation splits are sought after.

Fawn Mutation

Name	Fawn
AKA	Sometimes referred to as the Isabel or Brown.
Genetic Inheritance	The Fawn Mutation is recessive.
Characteristics	All of the bird's eumomelanin is missing giving the bird a brown-fawn appearance. Two variations are recognised and referred to as red-brown and black-brown, the latter being darker in colour and less 'ginger'.
Availability	A very common and popular mutation, with a large following of fanciers. Available worldwide.

Silver Mutation

Name	Silver
AKA	Sometimes referred to as the Opal.
Genetic Inheritance	The Silver Mutation is recessive.
Characteristics	All of the bird's phaeomelanin is missing giving the bird a pale-grey appearance.
Availability	Another very common and popular mutation, with a large following of fanciers. Available worldwide.

White Mutation

Name	White
AKA	Sometimes referred to as the Black-eyed Whites or Pure Whites.
Genetic Inheritance	The White Mutation is recessive.
Characteristics	All traces or plumage colour is removed showing no trace of phaeo or eumomelanin, just pure white feathers. Beak, leg and eye-ring colour is unaffected.
Availability	Although not yet common, this mutation is becoming far more easy to come by, with many JSSUK members able to supply not only as prime examples but also in combinations with Silver and Fawn.

Pied Mutation

Name	Pieds
AKA	Pied variations have lead to some patterns of markings being named individually, such as the saddle-back and white-headed pieds.
Genetic Inheritance	The Pied Mutation is recessive, though splits may sometimes be discernible from white tick marks, mostly appearing on the throat and wing edges.
Characteristics	Patches of white appear all over the birds plumage in haphazard patterns, ideally covering around 50% of the overall plumage.
Availability	Pied specimens are common in aviculture although many may be of reduced coverage, ideal 50% evenly marked birds being sought after.

Pastel Mutation

Name	Pastel
AKA	Sometimes referred to as the Dilute.
Genetic Inheritance	The Pastel Mutation is sex-linked.
Characteristics	The overall body colour is muted, whilst retaining all of the bird's phaeomelanin a certain amount of eumomelanin is lost in varying amounts giving its appearance a 'dilution' of colour.
Availability	Although not yet common, this mutation is becoming far more easy to come by, with many JSSUK members able to supply not only as prime examples but also in combinations with Silver and Fawn.

Agate Mutation

Name	Agate
AKA	Not known by any other name tmk.
Genetic Inheritance	The Agate Mutation is recessive, though breeding trials are yet to confirm this.
Characteristics	The head colour of the agate is dark brown and seemingly void of eumomelanin, though other areas remain grey, unlike the Pastel. Nestlings appearing ginger in colour.
Availability	This mutation is rare in aviculture. A dedicated group of breeders are currently working to establish this mutation within the JSSUK.

Cheekless Mutation

Name	Cheekless
AKA	Sometimes referred to as the black-headed.
Genetic Inheritance	The Cheekless Mutation can be recessive, but as yet this has not been established due to the appearance of many 'freak' occurrences within aviculture which proved to have uninheritible traits.
Characteristics	The body colour is identical to the normal type bird missing only its characteristic white cheek.
Availability	A very rare mutation with very few identified breeders currently working on collections above a single bird.

Cream Combination

Name	Cream (Pastel Fawn)
Combination	Although often referred to as a mutation, the Cream is actually the combination of two separate mutations, the Fawn and the Pastel.
Genetic Inheritance	See individual mutations for advice.
Characteristics	The Cap and abdomen of this combination are a warm pale brown, chest colour is white and wings and back very pale cream.
Availability	Although not yet common, this combination is becoming far more easy to come by, with many JSSUK members able to supply.

Opal Isabel Combination

Name	Opal Isabel
Combination	This is the combination of two separate mutations, the Fawn and the Silver.
Genetic Inheritance	See individual mutations for advice.
Characteristics	The Cap and abdomen of this combination are a warm pale brown, chest colour is pale cream and wings and back very pale fawn.
Availability	Although not yet common, this combination is becoming far more easy to come by, with many JSSUK members able to supply.

Ivory Combination

Name	Ivory
Combination	Although claimed as a 'new mutation' by certain suppliers this is actually the combination of three separate mutations, the Fawn, the Pastel and the Silver.
Genetic Inheritance	See individual mutations for advice.
Characteristics	The Cap and abdomen of this combination are a palest cream, chest colour is white and wings and back ivory.
Availability	This combination is rarely offered as the excessive combination often results in very washed-out colour appearance, frequently coupled with a lack of size and vigour.