As always, I put a handful of sawdust in the bottom of the box first, just in case the birds are minimalists and don't use anything. Incubation starts somewhere after the 3rd or 4th egg and lasts for 13-15 days. They take several months to fully molt into their adult plumage.(Fledged Java still in juvenile plumage)They'll breed just about anytime the weather is suitable.
Despite their large size and formidable beak, Javas are peaceful birds.Like most members of the Lonchura family, the males sing and perform a little dance.The dance is not much to see and many don't think much about the song, but I find it a pleasant, tropical sounding song.You can use a standard finch mix, but these often contain a number of smaller millets that the Javas will ignore until the last large white millet is gone.You can also offer them just plain White Prosso and any other seeds in a separate dish.