Baudin's and Carnaby's Black Cockatoos
Calyptorhynchus baudinii and C. latirostris

These two black cockatoos a pair of a pair of very similar white-tailed black cockatoos. Both species are endemic to the south-west of WA and despite favouring different habitats, they can often be found in mixed flocks. Visually, they are very close with the main difference being the width and length of the beak: Baudin's has a long beak (also know as Long-billed Black Cockatoo) and Carnaby's is shorter and wider (also known as Short-billed Black Cockatoo) although this can be difficult to see sometimes if the facial feathers are obscuring the bill. A more useful identifier is the call - the general rule is the long-billed has a short call and vice-versa. The different bill lengths between the two species are determined by their diet - the longer bill of Baudin's is better for extracting seeds from cones, the seed pods of the marri gum and from banksias while Carnaby's is suited for smaller seed capsules and ground-feeding. As with other black cockatoos, the male has a grey beak while the female's is white. Both species are the same size at 53-60 cm in length. The first photo is a male Baudin's and the last is a group of Carnaby's, all of which were in a mixed flock.
 

1-2: Porongurup, WA, 29/09/2012.