As per Wikipedia it is listed as endangered having been downgraded from critically endangered due to the spread in sightings over the years over a large area. Sightings have been rare with a reported sighting on 12th April 2005 and a dead specimen found in 2006 The first photos and a 17 second video of the bird was taken by a wildlife photographer John Young in 2013. Details can be found in this link.
According to Birdlife.org the reason for its population to decrease significantly include predation by feral cats and foxes, altered fire regimes, competition for food, degradation of habitat near water by stock or rabbits, and reduced availability of water as a result of over-use by feral camels.