Little Corella
Cacatua sanguinea

Little Corellas are members of the cockatoo family, closely related to the Long-billed Corella, differing mainly in size (38-41 cm for Long-billed against 36-39 cm for Little), beak length and the amount of red around the face - the Little having less. They are native to most of central Australia, but in the Sydney area they are thought to have been introduced although they may have been present before westerners landed. They can form huge flocks in rural areas, sometimes being a crop pest.
 

1: Monash University, Victoria, 27/04/2012.
2: Victoria Park, Sydney, NSW, 26/02/2010.