The Philippine Cockatoo , locally known as the 'Kalangay' was once so abundant in the Polillos that it was considered a rice pest. In 1910, McGregor observed a roost of several hundred kalangay on Polillo, owever, within a hunter's lifetime, the population has plummeted dramatically. Recent primary observations were confined to Patnanungan Island within small pockets of forest with relatively few large trees.

Internationally recognised as Critically Endangered, this species is thought to have undergone a decline of at least 80% over the last 10 years or three generations (Collar et al 1999, designation-A1). Further, there are believed to be fewer than 250 mature individuals remaining and its continuing decline rate is estimated to be at least 25%/generation (C1). The population structure of C.haematuropygia, is so severely fragmented that no subpopulation is believed to contain more than 50 mature individuals. With a clutch size of only 1-3 eggs (and infrequent breeding) this species has very limited resilience to persecution.

There is an urgent need to establish protection measures for the remnant patches of forest and mangroves and to safeguard against hunting. In the past loggers supplemented their income by catching birds either as nestlings or alternatively using the sticky 'antipolo' sap. In the days when the cockatoo was abundant sales reached about 5 pesos/piece, however more recently it is speculated that they reach 1000-3000 pesos, the latter price expected in Manila. That a remnant of hunting persists today seems likely and is most serious considering the tiny population remaining, the lack of large trees for breeding and perhaps most crucially the species open vulnerability to hunters