The Australasian Bittern (Botaurus poiciloptilus) is a heavy-set, partially nocturnal heron with upperparts that are patterned dark brown, buff and black, and underparts that are streaked brown and buff. The eyebrow and throat are pale, and the side of the neck is dark brown. The bill is brown and the legs are greenish.

The endangered Bunyip Bird aka Australasian Bittern, is famous for its deep booming call – for thousands of years thought to be the sound made by the mythical Bunyip -  a creature from the aboriginal mythology of south-eastern Australia, said to lurk in swamps, billabongs, creeks, riverbeds, and waterholes. (Wikipedia)