It is a Citron Crested Cockatoo, I had one for over 10 years.
They are NOT a hybrid.
"These beautiful and smaller Cockatoos are native to Indonesia. They are endangered in the wild due to illegal pet markets and deforestation. 12 to 15 inches in size and 360 to 425 grams in weight, they are smaller than their Umbrella relatives yet larger than the Goffin's, Bare Eyed or Rose Breasted.
Citrons display a bright orange crest, unlike Sulphur Crested Cockatoos, that sport a bright yellow crest, They also have pale orange cheek patches and pale yellow under their wings. Eyes range from amber-brown to very black. The eye color variation may be related to males or females.
Citrons are usually found to be a quieter Cockatoo, not usually screamers. They are not, however, considered to be good talkers. You may get a Citron to learn five to fifteen words. They are curious pets, and usually very social. They can be taught to perform tricks and seem to enjoy entertaining. They are big chewers, so provide toys frequently and interchange toys to prevent boredom. "
From Birdfarm.com