It measures around 55-60 cm (22-24 in) in length and weighs between 500-1,000 g. It is a distinctive bird with a large crest and has one of the largest bills of any parrots (only the Hyacinth Macaw's is larger). This powerful bill enables Palm Cockatoos to eat very hard nuts and seeds that other species have difficulty accessing. The bill is unusual as the lower and upper mandibles do not meet for much of its length, allowing the tongue to hold a nut against the top mandible while the lower mandible works to open it. The Palm Cockatoo also has a distinctive red cheek patch that changes colour when the bird is alarmed or excited.