Java Sparrows eat grains and seeds. Their binomial Latin name, Lonchura oryzivora, translates to “rice paddy eater” because a flock of Java Sparrows can eat a lot of rice. Their flocks can exceed 200 individuals!
They build a nest from grass in bushes and tree cavities. They have large clutches of 4 to 8 eggs. Incubation takes around 14 days. Chicks are altricial (nearly helpless and requiring parental feeding and care) and take a relatively long 2 to 3 weeks to fledge.
They are considered Vulnerable on the IUCN Red List due to habitat loss and hunting, which means that they will be Endangered unless something changes.
On the other hand, Java Sparrows have been introduced to other tropical areas where they compete with local species for food. They are one of the only species in the world that is Vulnerable while also expanding their range.