The endangered Western Australian endemic Carnaby's Cockatoo Calyptorhynchus latirostris was studied by Denis Saunders from 1968 to 1996, and by Rick Dawson and Denis Saunders from 2009 to 2016. One breeding population at Coomallo Creek in the northern wheatbelt of Western Australia was studied intensively from 1969 to 1976, and then monitored in early September and November most breeding seasons until 1996. Monitoring resumed in 2009 following the same protocols used from 1977 until 1996, but with at least one extra monitoring visit, usually in January. This long-term research project has: confirmed that what was known as the White-tailed Black Cockatoo C. baudinii is two species, Baudin's Cockatoo C. baudinii in the forested southwest, and Carnaby's Cockatoo in the wheatbelt, and overlapping the range of Baudin's Cockatoo; demonstrated photographic techniques for identifying banded individuals; proved identification of individuals based on contact calls, and suggested using individual vocal recognition as a method of non-invasive monitoring of endangered bird species; demonstrated the loss of large hollow-bearing trees was greater than replacements were being established; revealed the high rate of loss of hollows in trees still alive; shown that lack of nesting hollows may be limiting breeding; demonstrated the efficacy of artificial hollows; established methods for establishing the timing of egg-laying based on measurements of eggs, and aging of nestlings; developed a method for assessing nestling condition based on body mass; and shown that total rainfall in the first half of autumn is a significant factor in timing of egg-laying. The conservation implications of this half-century of research on Carnaby's Cockatoo are discussed.