The Java Sparrow or Maya Costa in the Philippines (Padda oryzivora) is the largest of the Estrilidid finches and while not brilliantly colored it is a strikingly elegant bird. Javas are closely allied with the munias (Lonchura spp) and in keeping with that group are sexually monomorphic. These birds are widely kept in Java and overseas – including the Philippines where feral populations have long been established. There are also feral population established on Christmas Island (An Australian territory near Java), Hawaii and in Fiji according to Javas UK .

Timor Sparrow From http://www.sjdjavas.co.uk/news07.htm

There are actually two species within Padda, the other being the lesser known Timor Sparrow ( P. fuscata ) and the two species should never be housed together because of the risk of hybridization. Sadly, while the Java sparrow is relatively common in the Philippines (wild sourced feral birds sell for ~PhP800 a pair at Cartimar) its number have fallen perilously in Indonesia due to hunting for the bird-trade and is now listed as vulnerable under CITES. If you want to read more on in situ Java Sparrow conservation you may enjoy reading about the Prambanan Temple Project.

Java Sparrows In the Philippines
The withdrawal of the markets in the US and EU for wild sourced birds has thankfully saved the wild Java Sparrow here in the Philippines however as recently as 1990 significant numbers of wild birds were being exported – records show some 9000 wild Javas were legally exported (NSCB report). Even now, putatively captive bred birds are still being exported primarily to the middle east according to contacts in the trade at Cartimar. Remembering that the Philippines exported the local Strawberry finch into extinction, aviculturist here shouldn’t be complacent about exports they should breed Javas rather than rely on constantly dipping into the local population and remaining as “keepers” rather than breeders given the Indonesian experience.
 

Breeding

With all the gloom and doom out of the way the good news is that once established in captivity Java Sparrows are considered free breeders and aren’t difficult manage. That said please remember that most of the wild-type birds for sale here in the Philippines are exactly that wild birds and so aren’t easy to breed. If you want something easier go for the mutations (pieds, whites and creams are the most common) or carefully source your birds to ensure they are truly captive bred. Being interested in only normal birds myself, I found out too late about the origin of my birds – none the less I have managed to breed them this year.
As previously stated Javas are sexually monomorphic, a character they share with the other munas. This makes them difficult sex prior to breeding so unless you are very experienced – which I’m not – birds must be left to choose their own mates. In a large flight this is quite easy but if you have breeding cages or cabinets that will only accommodate two birds then serial introductions are the only the only sure option. Experienced breeders can often pick birds by slight differenced in feathering, beak shape and behavior but the methods aren’t fool proof. If you want to read about these please visit the SN Aviaries site  or the Java finch site. It is generally true that cock birds sing but conversely not all non-singers are hens. In my experience even giving individuals distinguishing colored rings and attempting to observe which birds were pairing off in a flight was difficult because my birds panic easily whenever I go near the aviary. To identify which birds were actually occupying nests I used a trick I saw on the internet – I put lipstick around the nest entrance and the birds occupying the nest marked themselves. Once nesting the sex of the birds can be determined as with any Estrilidid finch in that only the hen incubates at night and duties are shared during the day.
Javas don’t usually build a free standing nest but occupy hollows in trees and crevices in buildings. In captivity they will accept a budgie-type box or a large cane basket nest but my birds did nothing until give a ½ open style wooden finch box. I formed the initial nest using dried panicum and tiger-grass heads and let them to finish the nest with more of he same grasses. No soft lining materials were used by my birds despite the fact that feathers were offered. The clutch size for my birds is 4, with incubation taking 14 days and a further 30 days to fledge after hatching. Javas are not generaly worried by nest inspections but I don’t go in daily either.
Although I give my birds a daily ration of green panicum and Echinochloa (& sometimes rice), mashed egg and sprouted grain, Javas can probably raise their young on dry seed and leafy greens alone. Javas don’t usually take live food according to the Java finch site. My birds don’t seem to be affected by the presence of youngsters from the previous brood in the aviary however in cages & cabinets young should be removed as soon as they are independent.

Fledgling Java Sparrow

Young Javas , such as the fledgling shown in the accompaning photo acquire adult plumage at around 3 months but shouldn’t be bred from until they are one year old.
 

Care
The Jarva’s beak is large and powerful so giving them small grains like panicum and canary seeds is wasteful as they won’t ordinarily eat them so unless your birds are part of mixed finch collection including small grains is wasteful. I like to include oats in the mix rather than rice as dried paddy rice (palay) is it just a little too hard but ½ ripe (green) seeds are eagerly taken. My mix is US white millet, red millet, Japanese millet, rape and oats (2:1:1:0.1:0.1). A grit mix and cuttlebone is always on hand.  Clean water for bathing is essential for their well being. It seems they will drink soiled and contaminated water but for bathing it must be clean. As is common for many birds kept in small cages, rather than in aviaries, their toenails quickly become too long and will need regular trimming.

 Mutants and Color Forms
As previously stated I’m not into mutants and since a picture says a thousand words I recommend that readers should have a look at the photos on the Singing wings and the Java Links of SN Aviaries.  Pied birds result in crossing a normal type to a white but this risks contaminating your germ-line forever. In Australia there are probably no pure wild-type Javas left because of the constant crossing that goes on when mixed collections are not carefully managed. Given that wild-type birds are still available here, Philippine aviculturists should ensure that this doesn’t happen to the Java sparrow – as it is happening now to Zebras and Gouldians in the Philippines.