In a swamp just north of Newcastle a team of researchers is on the hunt for one of Australia's most secretive wetland birds, the Australasian bittern. The large, heron-like bird lives among the tall reeds of wetlands, mainly in south-eastern Australia. It is estimated there are only 2,500 left in the world. The team had been using "songmeters" to record the bittern's distinctive call and the source of its nickname, the bunyip bird. The team now pinned its hopes on a thermal imaging camera attached to a drone to get a visual confirmation of the sounds they recorded.