Black Palm Cockatoos - King of Cockatoos

Abstract

The Palm Cockatoo, Probosciger aterrirnus, is considered by some to be regal, the king of cockatoos. Others feel it has a sinister appearance but most will agree the Palm Cockatoo is a unique and fascinating bird.

The species is characterized by black plumage which is greyed by powder down. Its heavy beak is adapted for cracking hard seeds, which it does with ease. The highly specialized beak structure would seem to indicate co-evolution with a favored food item which, in this case, may be pandanus. Its naked red facial skin, capable of blushing, is unique in cockatoos. Oral and pharyngeal anatomy is also unique and highly specialized. Unlike other psittacines, the long bones of legs, especially the tibiotarsus, is unusually elongated and that part of the leg is sparsely feathered. The significance of these adaptations warrant further study.!«

Another area in need of study is Palm Cockatoo taxonomy. Probosciger is a monotypic genus. Palms range primarily on the Island of New Guinea which is divided into the independent country of Papua New Guinea on the east and West Irian, an Indonesian territory on the west. Palms are also found on some surrounding islands and the Cape York Peninsula in North Queensland Australia.1,2,3,s

Most authors refer to three subspecies of Probosciger aterrimus, all three found on New Guinea. Pa. aterrimus, the nominate subspecies, is reported from the Cape York Peninsula, but also ranges from the Aru Islands through southern Irian, eastward to the Gulf of Papua. Mr. Joseph describes the Cape York population as intermediate in size between goliath and aterrimus, speculating that it may be unique. The distance from the southern coast of New Guinea to the Cape York Peninsula is approximately 150 miles. Mr. Joseph also reported that the Cape York habitat was recently given protection from mining and agricultural utilization. Pa. goliath is the largest subspecies and ranges from the western Papuan Islands through western New Guinea (West Irian or Irian Jaya) in the region of the Vogelkop Mountains and eastwards through Papua New Guinea. Pa. stenolopbus is similar in size to Pa. goliath but reportedly has narrower crest feathers. It ranges from Japen Island through northern West Irian eastwards to Collingwood Bay in Papua.1,2,3,4,s

Subspecies distinctions are extremely vague and may, in fact, represent geographical races. Overlapping size and physical characteristics makes current pairing difficult. Genetic analysis may be necessary to determine the validity of described subspecies.

Size difference between sexes has been observed. The average weight for all males in the Avicultural Breeding and Research Center (ABRC) collection is 721 grams (range: 545 to 1092 grams), while the average for all females is 602 grams (range: 503 to 950 grams). Weight for Pa. goliath is generally considered to be 800 to 1100 grams and for Pa. aterrimus, 500 to 750 grams. Palms are monomorphic making surgical sexing (or other techniques) necessary for proper pairing. i ,5

Habitat preference is rain forest edges and adjacent eucalyptus forests. It often moves considerable distances from rain forest areas through drier eucalyptus in search of food. Wild diet includes fruits, nuts, berries, seeds and vegetable matter. A favored food item is the fruit of the Pandanus. While often referred to as a palm tree, Pandanus species are in a separate family, Pandanaceae, which is closely allied with palms. The thick, fibrous hull of Pandanus fruit is easily pried open by Palm Cockatoos to obtain the seeds.1,3,6

Nesting season in the wild is reported to be August to January. The nesting site is usually a vertical hollow trunk with a deep cavity which is filled with chewed wood debris supposedly to allow drainage of rain water.

In 1987, Palm Cockatoos were added to Appendix I of the Convention on International Trade in Endangered Species (CITES). The species is also protected in both Indonesia and Australia. Several shipments of birds were imported in 1983 utilizing Malaysian documentation. Two shipments were confiscated and subsequently were distributed to zoos and private aviculturists with the stipulation they must be maintained in a studbook and Species Survival Plan (SSP). ABRC is participating in the SSP program.

Palms have been bred inconsistently and infrequently. The first reported captive breeding was in Australia in 1912 by W.R. McLennan. Reports typically detail attempts which often end in failure. Sindel and Lynn determined, after extensive review of the literature, that Bob Lynn of Sydney, Australia, had the world's first breeding in 1968. The chick was parent reared.