Probosciger aterrimus

Geographic Range

Palm cockatoos are found in the Australasian region, including New Guinea, the Cape York Peninsula (Northern Australia), Aru Islands, West Irian, Misool Isle (Western Papuan Islands) and other islands. There are three subspecies, P. a. atterimus , found in the Misool Isles, Aru Islands, and Northern Australia, P. a. goliath , the largest of the subspecies, found in Western Irian and the Papuan Islands, and finally P. a. stenolopus , in New Guinea and Western Irian.

• Biogeographic Regions
• australian australian
  • native native

Habitat

Palm cockatoos are found in rainforests, including gallery forests, forest edges, monsoon woodlands, eucalypt and paperbark woodlands, partly cleared areas, and dense savannas. They choose large trees for nesting and roosting. During the day they roost near food or water sources and at night roost in or near a nest tree.

• Habitat Regions
• tropical tropical
• terrestrial terrestrial

• Terrestrial Biomes
• forest forest
• rainforest rainforest

• Other Habitat Features
• riparian riparian

Physical Description

Palm cockatoos are the largest of all parrots, ranging from 49 to 68 cm in height. They weigh 500 to 1100 g, with females ranging from 500 to 950 g and males ranging from 540 to 1100 g. Wing length is around 35.1 cm, tail length 23.8 cm, bill length 9.1 cm, and tarsus length averages 3.5 cm.

Palm cockatoos are almost all black with a 15 cm erectile crest on their head. Their beaks never close completely, always revealing a bit of their black-tipped red tongues. This partly open mouth makes it easier for the birds to hold nuts in their mouth and crack them at the same time. Their strong mandibles are used for cracking nuts and are larger in males than in females. Their legs are grey/black with few feathers on their thighs and their red facial markings are their most distinguished characteristic. Their cheek skin changes color based on their health or level of stress so when highly stressed the skin will change color to a pink/beige, while when highly excited the skin changes to yellow. In young birds, the underfeathers are lined with a pale yellow and in very young birds (under 18 months old), the tip of the bill and the eye ring are white.

• Other Physical Features
• endothermic endothermic
• homoiothermic
• bilateral symmetry bilateral symmetry

• Sexual Dimorphism
• male larger

Reproduction

During mating the male and female approach each other with wings extended. Before mating the male makes loud whistles and bows several times during which the skin on the face will usually become a deep red. Sometimes the male will also bang a stick against a tree while calling out, as a territorial gesture near the nesting sight. Palm cockatoos are monogamous and stay together for life.

• Mating System
• monogamous monogamous

The mating season varies with local climate, but is usually from August to January. Palm cockatoos cannot excavate their own nesting cavities. Instead they use previously hollowed cavities in large trees, such as palms. Their nesting holes tend to be about 1 m in depth and 25 to 60 cm in diameter are are lined with a pile of broken twigs at the bottom, upon which the egg rests. The same site is often used year after year.

Palm cockatoos lay one egg per clutch, which is incubated for 30 to 33 days. The newly hatched young are naked and helpless. They take 100 to 110 days to fledge, the longest period to fledging of any parrot species.

After leaving the nest, the young bird is dependent on the parents for at least another 6 weeks because of its inability to fly. After this, the young bird will be independent, but will stay relatively close to the parents until the next breeding season, whereupon the parents evict the previous year's young from their territory. Young birds are estimated to reach sexual maturity at 7 to 8 years old.

• Key Reproductive Features
• iteroparous iteroparous
• seasonal breeding seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual sexual
• oviparous oviparous

Although both parents participate in incubation, females incubate the egg more than males and males spend more of their time foraging for food. After hatching, chicks are brooded mostly by females. Males also brood the young, but are mainly responsible for finding food. After the chick leaves the nest, both parents provide food and protection for it until it is fully independent.

• Parental Investment
• altricial altricial
• pre-fertilization
  • provisioning
  • protecting
    • female
• pre-hatching/birth
  • provisioning
    • female
  • protecting
    • male
    • female
• pre-weaning/fledging
  • provisioning
    • male
  • protecting
    • male
    • female
• pre-independence
  • provisioning
    • male
    • female
  • protecting
    • male
    • female
• post-independence association with parents

Lifespan/Longevity

The lifespan of wild palm cockatoos is not well known. Other cockatoo species live from 40 to 60 years in the wild. Captive cockatoos may live to more than 100 years old.

Behavior

Wild and captive birds behavior differently. Captive birds may develop compulsive behaviors, such as feather picking. They can also mimic human sounds and language. Wild palm cockatoos are bold and will accept food from humans and raid bird feeders. When food sources become low, they have been known to chew up decks and side paneling on homes.

Palm cockatoos can be found alone, in pairs, and in larger groups. They spend a lot of their time high in the forest canopy or flying between roosting and foraging areas. They often feed in large groups, where one "sentinel" bird will watch out for predators. If a predator or any other threat should appear, the “sentinel” gives an alarm cry to alert the rest of the flock. They are highly social, gathering in groups early in the day in favorite locations where they spend time preening and interacting. In rainy conditions they can be found hanging upside down with their wings and tails stretched out, as if taking a bath.

• Key Behaviors
• arboreal arboreal
• flies
• diurnal diurnal
• motile motile
• sedentary sedentary
• territorial territorial
• social social

Home Range

Palm cockatoos sometimes remain quite close to their nesting sites, but can travel long distances in search of food or water. Their territory includes several possible trees for nesting sites. They will visit these sites throughout the year for various reasons, increasing the frequency of these visits during the breeding season.

Communication and Perception

Palm cockatoos are one of the loudest parrot species, making loud whistling calls. The most common call heard is the contact call which is a disyllabic whistle. When they are alarmed they produce a sharp, harsh screech. Other calls include grunts, mournful/wailing cries, whistles, and screeches. Another way they communicate is by stomping noisily on a perch, using sticks or nuts to drum against the tree, sometimes up to 200 times. This is usually used to advertise territorial boundaries. Their cheeks will change color with mood, stress, and health. They also use their erectile crest to communicate mood.

• Communication Channels
• visual visual
• acoustic acoustic

• Other Communication Modes
• mimicry mimicry

• Perception Channels
• visual visual
• tactile tactile
• acoustic acoustic
• chemical chemical

Food Habits

Palm cockatoos mainly eat leaf buds, seeds, and fruits. They sometimes also eat insects and their larvae. They forage primarily in the forest canopy, but may also forage on the forest floor for fallen fruits and seeds. They crush seeds and hard fruits with their sharp, strong mandibles.

• Primary Diet
• herbivore herbivore
  • frugivore frugivore
  • granivore granivore

• Animal Foods
• insects

• Plant Foods
• leaves
• seeds, grains, and nuts
• fruit

Predation

Confirmed reports of predation on palm cockatoos was not found. However, common brushtail possums steal eggs from glossy black cockatoo nests, a close relative of palm cockatoos. Egg predation was found to greatly reduce the population size of the glossy black cockatoos . Arboreal snakes are also potential nest predators. Large birds of prey may take adults.

Competition between cockatoo species for nesting sites is high, and may result in egg or nestling death when cockatoo individuals fight over a nest.

Ecosystem Roles

Palm cockatoos aid in the dispersal of seeds for many fruit-bearing trees. Many plant species have evolved methods to attract large, frugivorous birds to further enhance the probability of seed dispersal.

• Ecosystem Impact
• disperses seeds

Economic Importance for Humans: Positive

Palm cockatoos are sometimes kept as pets or in zoos because people enjoy the intelligence, sociality, and vocal dexterity of parrots. Unfortunately, trade in cockatoos sometimes harms wild populations.

• Positive Impacts
• pet trade pet trade
• ecotourism ecotourism
• research and education

Economic Importance for Humans: Negative

Because palm cockatoos take quickly to accepting food from humans, they are known to raid bird feeders. They may destroy wood decks and the paneling of houses.

• Negative Impacts
• household pest

Conservation Status

Palm cockatoos are considered near threatened or low risk due to the destruction of habitat with logging and seasonal fires. Additionally, in the 1970s, keeping palm cockatoos as pets became quite popular, and since then they have been the object of hunting for the aviary trade with the most popular tactic of capture involving arrows covered in sticky resin. There are now laws that prohibit the export of any palm cockatoo without a permit. Unfortunately, many are still illegally exported and sold as pets, and they do not survive well in captivity.

Other Comments

Probosciger aterrimus , is derived from the Greek words " proboscis " which means nose and " gero " which means to carry. The specific name is from the Latin " aterrimus ," meaning very black.

Additional Links

Encyclopedia of Life

Contributors

Tanya Dewey (editor), Animal Diversity Web.

Justine Zingsheim (author), Kalamazoo College, Ann Fraser (editor, instructor), Kalamazoo College.

References

Filardi, C., J. Tewksbury. 2005. Ground-foraging palm cockatoos (Probosciger aterrimus) in lowland New Guinea: fruit flesh as a directed deterrent to seed predation?. Journal of Tropical Ecology , 21: 355-361. Accessed November 11, 2006 at http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=315507 .

Heinsohn, R., S. Murphy, S. Legge. 2003. Overlap and competition for nest holes among eclectus parrots, palm cockatoos and sulphur-crested cockatoos. Australian Journal of Zoology , 51: 81–94. Accessed November 11, 2006 at http://publish.csiro.au/paper/ZO02003.htm .

Rauzon, M. 2001. Parrots Around the World . New York: Franklin Watts, a Division of Grolier Publishing.

Silverstein, A., V. Silverstein, L. Silverstein Nunn. 2003. Beautiful Birds . Brookfield, Connecticut: Twenty-First Century Books.

Taylor, M. 2006. "General Characteristics and Natural History" (On-line). Accessed November 09, 2006 at http://www.funnyfarmexotics.com/PALM/chapter1.htm .

2006. "Animal Bytes: Cockatoo" (On-line). Zoological Society of San Diego. Accessed October 13, 2006 at http://www.sandiegozoo.org/animalbytes/t-cockatoo.html .

2006. "Fact Sheets: Palm Cockatoo" (On-line). Smithsonian National Zoological Park. Accessed September 30, 2006 at http://nationalzoo.si.edu/Animals/Birds/Facts/FactSheets/fact-palmcockatoo.cfm .

2003. "Nature Feature (Probosciger aterrimus)" (On-line). Accessed November 12, 2006 at http://www.australianstamp.com/coin-web/feature/nature/palmcock.htm .

2006. "Palm Cockatoo" (On-line). Honolulu Zoo. Accessed September 30, 2006 at http://www.honoluluzoo.org/palm_cockatoo.htm .

2006. "Parrots: Cockatoos" (On-line). Natural Encounters Inc. Accessed September 30, 2006 at http://www.naturalencounters.com/abby3a.html .

2006. "Threatened Species - South Australian Glossy Black-Cockatoo - A Gradual Recovery" (On-line). Biodiversity. Accessed November 11, 2006 at http://www.environment.sa.gov.au/biodiversity/glossyblack.html .