The Australasian Bittern, Botaurus poiciloptilus, also known as the Brown Bittern, is found in south-western and south-eastern Australia, Tasmania, New Zealand, New Caledonia and Ouvea. Populations in Australia and New Zealand have declined in the 20th Century.
It is a large bittern, patterned and streaked brown, buff and black, with a pale throat. It is a cryptic and partly nocturnal species that inhabits densely vegetated wetlands. It feeds on aquatic animals such as frogs, eels and freshwater crustaceans. It is a solitary nester on the ground in dense wetland vegetation on trampled reeds and other plants. It has a distinctive booming voice and may be heard more often than seen.
The principal cause of past and ongoing decline is thought to be wetland drainage and degradation. In Australia it is though to be particularly sensitive to the destruction of drought refugia.