- red-vented cockatoo (Cacatua haematuropygia)
- 560–1,150 total number
- Philippines ()
The world's rarest species of cockatoo is the red-vented cockatoo Cacatua haematuropygia, endemic to the Philippines and once common there, but nowadays with only remnant populations scattered among a few islands. Today, a total number of only 560–1,150 individuals is estimated to remain in the wild, after the species has suffered an extremely rapid decline owing to destruction of its lowland forest habitat and capture by the cage-bird trade. It is currently categorized as Critically Endangered by the IUCN.
The only other species of cockatoo currently categorized as Critically Endangered by the IUCN is the yellow-crested cockatoo C. sulphurea, native to wooded and cultivated areas in East Timor on the island of Timor and to the Indonesian islands of Sulawesi and the Lesser Sundas. Illegal trapping for the cage-bird trade has caused its population to decline dramatically, with an estimated total number of around 7,000 individuals currently existing in its native islands homeland. Interestingly, an additional wild-living population exists in Hong Kong, having established itself from escaped and released cage-birds successfully breeding there.