Palm Cockatoo Probosciger aterrimus


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Palm Cockatoo Probosciger aterrimus
  • LC Least Concern
  • Names (16)
  • Subspecies (3)

© raniero massoli novelliWoollahra, New South Wales, Australia 01 Aug 2001

with naked scarlet cheek patches and long, backward-curving crest 

© Tomasz DorońBerlin, Germany 30 Sep 2009

gape  red, tongue red with black tip; massive bill  grey-black 

© Lars PeterssonPapua Barat, Papua, Indonesia Macaulay Library ML 205931391

, with upper mandible 94 mm long in male, 74 mm in female; eye dark brown; legs grey to black (1) with bare grey thighs. Female also has smaller cheek patches (1). Immature has feathers of underparts and underwing-coverts (1) edged pale yellow, as well as white tip to bill (lost after c. 18 months) and eyering, with paler pink facial skin (1).

Systematics History

Internal taxonomy uncertain; phylogeographical study (2) identified two main clades: one in W, corresponding approximately with race goliath; and the other in E, where small genetic differences among populations render delimitation of races very difficult and perhaps unreliable; present arrangement provisional, pending further investigation. Proposed race alecto (W Papuan Is) is here included within goliath; form intermedius (Aru Is) is a synonym of nominate. Original type locality of species probably based on faulty citation of Latham referring to another species of cockatoo. Four subspecies tentatively recognized.

Subspecies

Introduced (possibly nominate race) to Kai Is, in SE Moluccas.


SUBSPECIES

Probosciger aterrimus stenolophus Scientific name definitions

Distribution

N and E New Guinea (from Mamberamo R E to Collingwood Bay) and Yapen I (in Geelvink Bay).

Identification

Larger than nominate, with narrower crest feathers.

© Mehd HalaouatePapua, Papua, Indonesia Macaulay Library ML 205941011

SUBSPECIES

Probosciger aterrimus goliath Scientific name definitions

Distribution

W Papuan Is (except Misool), and W, C (except S Trans-Fly) and SE New Guinea.

Identification

Larger than nominate.


SUBSPECIES

Probosciger aterrimus aterrimus Scientific name definitions

Distribution

Aru Is., Misool I., s New Guinea and ne Australia (Cape York)

Distribution

Editor’s Note: Additional distribution information for this taxon can be found in the ‘Subspecies’ article above. In the future we will develop a range-wide distribution article.

Habitat

In New Guinea 

© Lars PeterssonPapua Barat, Papua, Indonesia Macaulay Library ML 205950661

, frequents rainforest, gallery forest (1), forest edges, partly cleared areas, tall secondary forest, monsoon woodland and, locally, dense savanna. Mostly in lowlands and hills up to 1350 m, but commonest below 750 m (1). On Cape York Peninsula  , frequents fringe zone between lowland monsoon forest and adjacent Eucalyptus woodland, as well as dense savanna and paperbark woodlands (1). In Australia, most abundant in woodland, rather than rainforest (3).

Movement

Territorial pairs are resident in a patch of forest that provides several nest-hollows. Pairs 

© Lars PeterssonPapua Barat, Papua, Indonesia Macaulay Library ML 205950651

may associate together in flocks of up to 30 birds when foraging outside the territory wherever fruiting trees are available, but return to roost in their territories at night, where they are intolerant of other conspecifics.

Diet and Foraging

Chiefly arboreal feeder  , taking seeds, fruits, nuts  , berries and buds from a wide variety of plants, particularly Pandanus palm nuts and Castanospermum australe (1); occasionally eats fallen fruits on the ground  , especially seeds of Terminalia kaernbachii and Canarium (1). Nuts are routinely cut in half using the massive bill (1).

Sounds and Vocal Behavior

Wide variety of calls, all of which are generally higher-pitched than those of Cacatua galerita, while the frequently-uttered bisyllabic whistled  contact call is less harsh and grating than in Calyptorhynchus species, with the first note mellow and deep, the second shrill, high-pitched, prolonged and ending on an abrupt upward-inflection; also more raucous calls including a far-carrying, donkey-like “keeyaank!”, “eeyohn!” or “raah!” and a sharp guttural screeching (1).

Breeding

Laying recorded Jul–Mar. Pairs are territorial and resident, nesting in hollows high (1) in the trunk of dead or living trees (in Australia, Eucalyptus tetrodonta or Corymbia nesophila and C. clarksoniana are the most frequently used tree species) (3); hollow is lined with freshly shredded twigs and wood chips (1) prepared by both members of pair; lining sometimes up to 1 m deep (1). Species builds nests in multiple hollows, a subset of which are used for actual breeding whereas the rest are used only for display 

© Lars PeterssonPapua Barat, Papua, Indonesia Macaulay Library ML 205950671

purposes (3). Both partners have been seen to give spectacular drumming display at nest-hollow, using specially prepared stick or Grevillea glauca nut as a tool; drumstick is held in foot and beaten against hollow trunk. Usually one white egg (1); incubation c. 30–35 days (1) by female, which is fed by male; hatchling naked, not downy as in other cockatoos; nestling remains in the hollow for 100–110 days (1) and is fed by female; in captivity, fledging 78–81 days. On fledging, young bird remains with parents until next nesting season approaches and continues to be fed by adults for c. 6 weeks after leaving nest (1). Nest success 22% in N Australia in 1999 (4), but 40% in Crater Mountain (Papua New Guinea) (5); major nest predators include varanid lizards (Varanus spp.), giant white-tailed rats (Uromys caudimaculatus), Black Butcherbirds (Melloria quoyi) and amethyst pythons (Morelia amethistina) (5). Furthermore, reproductive rate is very slow, as females in Iron Range National Park, on Cape York Peninsula, only breed on average every 2·2 years (5).

Conservation Status

Conservation status on BirdlifeLC Least Concern

Not globally threatened. CITES I. Previously considered Near Threatened. Much sought after for aviary trade, which is illegal in Australia; development of methods to distinguish between Australian and New Guinea birds would help the authorities to police this trade; may be seriously affected by this factor, and listed on CITES I since 1987. In New Guinea, extent of lowland rainforest habitat has been notably reduced by logging, which continues. Remains common in Fakfak Mts, SW Irian Jaya (6). Status in Australia rated insufficiently known; the ecotone between tropical forest and woodland has been little modified, but more frequent and mismanaged fires late in dry season may destroy significant numbers of nest-hollows; a study conducted between 1999 and 2005 focusing on a mean 48 nest-trees each year found that 26·2% trees were rendered unusable by the cockatoos due to fire (62·5%), wind (25%) and intense decay, where the tree was left standing but unusable (12·5%), with on average, 5·2% of nest-trees lost each year of the study; on the other hand, tropical cyclones can be a positive agent for creating nesting habitat (3). Like many other birds restricted in mainland Australia to N Queensland 

© Jennifer SpryCook, Queensland, Australia 25 Oct 2005Macaulay Library ML 204356921eBird S64979670

, it is poorly known among the country’s general public, which does not facilitate its conservation (7). Species (especially nestlings) (5) hunted for food in New Guinea, and possibly on Cape York too; high rates of nestling predation in Papua New Guinea and low reproductive rate in Australia suggest that in the long term the species is at some risk (5). Captive-breeding programmes in Europe and North America.


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