The above images are of a Sulphur-crested Cockatoo (Cacatua galerita).
As you can see from the image, they are a large white bird with a sulphur coloured crest and part of their underwing and tail is also tinged a pale yellow colour. They appear to fly and feed in large flocks, I observed them in flocks of up to eight or ten. They have an incredibly harsh and almost eerie sounding loud and piercing call which resonates through the forest heralding their arrival. I noticed that when Sulphur-crested Cockatoos came to feed at the bird table in the above photograph, all the other birds in the vicinity made themselves scarce. The Sulphur-crested Cockatoos appear to take advantage of their size (their total length can be up-to 55cm long) and the fact that they fly in large flocks to bully other birds out of the way.
The Sulphur-crested Cockatoo (Cacatua galerita) is a relatively large white cockatoo found in wooded habitats in Australia and New Guinea. They can be locally very numerous, leading to them sometimes being considered pests. They are well known in aviculture.
There are four recognised subspecies;
Within Australia, Sulphur-crested Cockatoos of the nominate race have also been introduced to Perth, which is far outside the natural range. Outside Australia, they have been introduced to Singapore, where their numbers have been estimated to be between 500 and 2000. They have also been introduced to Palau and New Zealand. In New Zealand the introduced populations may number less than 1000. This species has also been recorded as established in Hawaii and from various islands in Wallacea (e.g. Kai Islands and Ambon), but it is unclear if it has managed to become established there.
The plumage is overall white, while the underwing and -tail are tinged yellow. The expressive crest is yellow. The bill is black, the legs are grey, and the eye-ring is whitish. Males typically have almost black eyes, whereas the females have a more red or brown eye.
Their distinctive raucous call can be very loud; it is adapted to travel through the forest environments in which they live, including tropical and subtropical rainforests. These birds are naturally curious, as well as very intelligent.
These birds are very long-lived, and can live upwards of 70 years in captivity, although they only live to about 20–40 years in the wild. They have been known to engage in geophagy, the process of eating clay to detoxify their food. These birds produce a very fine powder to waterproof themselves instead of oil as many other creatures do.
Species that feed on the ground are very vulnerable to predator attack. The Cockatoo has evolved a behavioural adaptation to protect against this: whenever there is a flock on the ground, there is at least one high up in a tree (usually a dead tree), keeping guard.