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.
 
 


Normal -
A.K.A Wild Type, Grey or even Native colour.

Characteristics - The photo (left) illustrates how the "normal" is found in the wild. Its slick grey feathering is seamless and thereare no white feathers present anywhere on the bird's body except in the cheeks and the under the tail feathers.

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 -
A.K.A Isabel or Brown.

Genetics - 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 beige-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 -
A.K.A Opal.

Genetics - 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 -
A.K.A Black Eyed Whites or Pure Whites.

Genetics - 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 - A fairly common mutation and popular with JSSUK members.

         
 
 


Pied

Genetics - 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 - Pieds are common although many may be of reduced coverage, ideal 50% evenly marked birds being sought after.

 
         
 
 


Pastel -
A.K.A Dilute

Genetics - 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.

 
         
 
 

Agate - A.K.A "Topas" in Europe and "Cherry Blossom" in Japan.

Genetics - 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 -
A.K.A Black-Headed

Genetics - This 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 slightly darker than the normal type and the white cheeks are missing. Usually after 2nd adult moult the white cheeks appear.

Availability - Very rare with only a few known to be within the JSSUK.

Cream - A.K.A Pastel/Dilute Fawn

Combination - Although often referred to as a mutation, the Cream is actually the combination of two separate mutations, the Fawn and the Pastel

Genetics - 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 - This is the combination of two separate mutations, the Fawn and the Silver.

Genetics - 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 - Fairly common, this combination is becoming far more easy to come by, with many JSSUK members able to supply.

   
 

Ivory

Combination - Claimed as a "new mutation", this is actually the combination of three separate mutations, the Fawn, the Pastel and the Silver.

Genetics - 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.