Java finches are small birds with cone-shaped beaks that are commonly kept as pets. If you're considering breeding your Java finch, consult with your vet first. Finches will only breed when they are in ideal physical condition, and no finch should be bred before it is 1 year old. It can be challenging to locate qualified homes for babies, so it's vital that you have enough space and time to care for the finches' offspring in case you are unable to find new homes for them.
Ask your vet to definitively sex your finches. Java finches are notoriously difficult to sex and it's vital that you have one male and one female in order to breed them. As a general rule, only the male finch sings, but a bird who does not sing is not necessarily a female.
Keep the finches separate until you are ready to breed them. This encourages mating behaviour and makes the male more likely to build a nest when he is placed with the female.
Place a nest box in your finch's cage. Most pet and bird speciality stores carry finch nesting boxes. Add extra substrate to the cage as well. Cocks actively build nests before mating, so providing your male with hay, straw and other material with which to make a nest will stimulate mating behaviour.
Put the two finches in the breeding cage together. Cocks begin building a nest before mating occurs, so if you see the cock working on a nest, mating will occur soon. The female should lay eggs between eight and 15 days after the pair is placed together with a nest box. If there are no eggs after three weeks, separate the birds for a week, and then reunite them to attempt mating again.
Wait for the hen to lay eggs. Hens normally lay one egg per day. Mist the eggs when the eggs begin to look dry. The female will incubate the eggs on her own, but will not begin sitting on them until she is finished laying. The eggs hatch 15 to 20 days after the female lays them.
Male finches are called cocks, and females are called hens.