This study determined methods for identifying individual Carnaby's Cockatoo Calyptorhynchus latirostris using natural variations in markings, to assist future research and management Photographs of wild and captive cockatoos and museum specimens were studied and a variety of useful identification characteristics were found. These included marks on subterminal tail panels, yellowish colouration, upper mandible markings, atypical white feathers, white panels on undertail coverts and grey areas in the ear covert patches of females. A combination of distinctive marks could sometimes be used to identify individuals. Distinctive markings may be short term and useful until the next moult, or longer term and maintained over years. Females provided more identifying marks than males, with 28.6% of preserved adult female tails having black spots and/or bars in their white tail panels compared to 5.0% of adult males, and 53.1% of immature females compared to 12.5% of immature males. The tails of immature C. latirostris were more commonly heavily marked, compared to adults, suggesting that marks, where present, are gradually lost over successive moults. This was confirmed by observations of heavily marked tails re-growing feathers without markings and with analysis of pentosidine concentration in skin to age six museum specimens.A gradual loss of spots and bars in subterminal tail panels in some Clatirostris may reflect the evolutionary history of this endangered endemic Western Australian species.