Palm Cockatoo (Probosciger aterrimus)


We determined that the species selected to commence this series should be one of the more spectacular parrots, and preferably one which is familiar to readers, though not necessarily common in aviculture. Our eventual choice was prompted by my recalling what probably was my most memorable field experience with parrots in Australia - my first sighting of a Palm Cockatoo at Iron Range, Cape York Peninsula, in November 1963.

Less than two hours after arriving at Iron Range airport, I was setting up camp in a rainforest clearing beside the Claudie River when a lone cockatoo flew into the uppermost leafless branches of a tall tree standing at the forest edge. Obviously alarmed at my presence, this bird climbed with slow, deliberate footsteps to the top of an emergent branch; alternatively placing one foot in front of the other, it advanced up the branch, regularly bowing forward and raising the spectacular crest while g1vmg loud, whistling call-notes. Sitting atop the projecting limb, it continued to scold loudly, with a flushing of the red cheekpatches being clearly visible, before eventually flying off through the forest canopy. On return visits to Iron Range, I have seen these majestic cockatoos numerous times and encounters always are exciting, but that initial sighting


Closely Associated with Rainforest

Palm Cockatoos are unmistakable, being readily identified hy the prominent, backward-curving crest of narrow, elongated feathers and an enormous black . hill, the mandibles of which meet at only one point thus exposing the small black-tipped, red tongue. Bare facial skin is crimson, while the general plumage is black with a slight hluish-grey suffusion coming from a heavy coating of powder-down on the feathers. A smaller bill distinguishes the adult female, while juveniles have feathers of the underparts finely edged with pale yellow and the bill is pale grey with a contrasting white culmen.


These cockatoos are distributed throughout the lowlands of New Guinea, and occur also on the Aru and western Papuan Islands, Indonesia, and on Cape York Peninsula, northernmost Queensland, Australia.

Subspecies are differentiated by size and by structure of the crest. Smallest birds belong to P. a. aterrirnus from the Aru and western Papuan Islands, and many of the pairs that I have seen in captivity are of this subspecies. A significantly larger size differentiates both P. a. goliath from the lowlands of western and southern New Guinea and P. a. stenolopbus from northern New Guinea, but the latter has much narrower crest feathers. P. a. macgilliurayi from Cape York Peninsula, northernmost Australia, and southern New Guinea, between the


Fly and Bian Rivers, is intermediate in size between aterrimus and goliath.

Closely associated with monsoonal rainforest, Palm Cockatoos commonly are seen at forest edges or in clearings, though also in tall secondary growth and tropical woodland. On Cape Yark Peninsula, I have found them to be very much birds of the ecotone, where rainforest meets Eucalyptus-Melaleuca woodland, and they seem to he more prevalent in the woodland, though rarely venturing more than a few hundred meters from rainforest margins. During the middle of the day they tend to retreat into the rainforest, presumably to shelter from the heat.

Conspicuous Interactions in the Earfy Morning

These cockatoos usually are encountered singly, in pairs or in small groups, the last being more prevalent outside the breeding season, hut occasionally larger flocks of up to 30 birds will congregate to feed. At Iron Range, I observed that they habitually roosted singly in the topmost branches of tall trees, and daily activities did not commence until about an hour after sunrise, when each bird spent some time preening before calling to another and then flying off to join with other birds at a favored tall tree in open woodland. At this 'congregating tree' the birds interacted with each other, performing bowing displays with wings outstretched and crests raised or making mock attacks in which two or more birds flew at another sitting nearby, Parties then drifted out from these 'congregating trees' to feed in open woodland until mid morning, when they retreated into the rainforest.

I found also that, while feeding in the rainforest, the cockatoos could be approached fairly easily, but in open woodland they are very shy, immediately flying off when disturbed, They feed on seeds, nuts, fruits, leaf buds and possibly insects and their larvae. Feeding is mostly arboreal, hut birds will come to the ground to pick up fallen seeds, and they have been seen scratching about in the soil along creek banks. On one occasion, I watched

seven birds feeding in a nonda tree Parinari nonda, under which the ground was littered with husks, twigs and fruit remains; the cockatoos showed surprising agility as they clambered about at the extremities of branches, often stretching out and down to get at fruits, which then were held in the foot while the bill was used to split them along the small axis and the seeds extracted.