The bush stone-curlew or bush thick-knee (Burhinus grallarius, obsolete name Burhinus magnirostris) is a large (55–60 cm wingspan), ground-dwelling bird endemic to Australia. Although it looks rather like a wader and is related to the oystercatchers, avocets and plovers http://en.wikipedia.org/wiki/Bush_stone-curlew
Like most stone-curlews, it is mainly nocturnal and specialises in hunting small grassland animals: frogs, spiders, insects, molluscs, crustaceans, snakes, lizards and small mammals are all taken, mostly gleaned or probed from soft soil or rotting wood; also a few seeds or tubers, particularly in drought years. Birds usually forage individually or in pairs over a large home range, particularly on moonlit nights
During the day, bush stone-curlews tend to remain inactive, sheltering amongst tall grass or low shrubs and relying on their cryptic plumage to protect them from predators. When disturbed, they freeze motionless, often in odd-looking postures. For visual predators like raptors (and humans), this works well, but it serves little purpose with animals that hunt by scent such as foxes, dingoes or goannas
The bush Stone-curlew is probably heard more than it is seen. Its call sounds like a wail or a scream in the night. When scared, it screeches – a sound similar to the screech of a possum. When threatened (presumably in the presence of a nest), they may raise their wings wide and high in an impressive threat posture and emit a loud, hoarse hissing noise
Despite their ungainly appearance and habit of freezing motionless, they are sure-footed, fast and agile on the ground, and although they seldom fly during daylight hours, they are far from clumsy in the air; flight is rapid and direct on long, broad wings.