They live in and around freshwater swamps, streams and marshes. This one was at the Dubbo Zoo.
You can find out more here at Birds in Backyards.
But their breeding I'll paste here, taken from the Birds in Backyards website, because it's interesting:
Purple Swamphens are generally found in small groups and studies have shown that these consist of more males than females.
More than one male will mate with a single female.
All family members, and occasionally the young from a previous brood, share in incubation and care of the young.
The nest consists of a platform of trampled reeds with the surrounding vegetation sometimes being used to form a shelter. Often two broods will be raised in a year.