Carnaby’s Black Cockatoos (Calyptorhynchus latirostris) and Red-tailed Black Cockatoos (Calyptorhynchus banksii naso) are often seen in Warwick Bushland and feed on trees. These impressively large birds, live for about 25 to 50 years, begin breeding at four years of age, mate for life and tend to nest in the same hollow each breeding season. Unfortunately, suitable nesting hollows are in short supply because feral honeybees and other birds that are new to urban bushland have occupied most of them. These two cockatoo species are closely related and primarily distinguished by red or white coloured bars under their tail feathers that are most visible when flying. Both species are endemic to Southwest Western Australia and are specially protected as they are considered at risk of extinction. Numbers of both species have declined overall due to the destruction of their habitat and competition for nesting hollows, but Red-tailed Black Cockatoos have recently become much more common in Perth.

Red-tailed Black Cockatoos feed primarily on the seed of native trees, such as Marri, Jarrah and Sheoak, as well as some urban landscaping trees. They use their powerful beaks to extract seeds from the fruits and nuts. Examples of chewed gumnuts are shown below. In Warwick Bushland they are primarily feeding on jarrah fruit leaving a carpet of chewed gumnuts and pruned branches under trees. Unfortunately, they prune off many branches that get in their way so that trees can look defoliated.