bluesdave is right .. they are nocturnal, and also very docile .. they specialise in shutting their eyes, never moving, and imitating pieces of dead wood .. which they do perfectly.
You can stand alongside them and not see them, with the right background.
Unfortunately, they are also ready to become an endangered species, due to their docility, and predation by animals such as cats and foxes. Land clearing has also reduced their habitat.
Scroll down this page to see some really good pics of them ..
http://www.bluemountains.net/birds/bird.asp?bird_id=96
Members of the podargus family, with several species, related more to nightjars than owls, they are spread from India, through S.E. Asia, to Australia ..
Here's a classic pic ..