Red Tailed Black Cockatoo

Red Tailed Black Cockatoo

Length: 2396 words (6.8 double-spaced pages)

Rating: Excellent

Open Document

Essay Preview

More ↓
Red Tailed Black Cockatoo


Calyptorhynchus banksii, or red-tailed black-cockatoo, has coped with extreme variations in its environment. Much like the plant species of Australia, the red-tailed black-cockatoo has evolved physiological and anatomical adaptations that have allowed it to survive in changing surroundings. One of the most prevalent adaptations was that seen in the beak apparatus. Changes in the beak allowed the cockatoos to consume the newly evolved sources of food. The metabolic requirements of the cockatoos and the availability of food are also forces that have influenced the beak apparatus and the distribution of red-tailed black-cockatoos throughout Australia.


Calyptorhynchus banksii, commonly known as the red-tailed black-cockatoo, is of the Family Cacatuidae (Cockatoos), which is a branch of the Order Psittaciformes. Red-tailed black-cockatoos are indigenous to Australia and can be found throughout the entire continent. Calyptorhynchus banksii is distinct in that there are five different subspecies: Calyptorhynchus banksii( C.b.) banksii, C.b. macrorohynchus, C.b. naso, C.b. graptogyne, and C.b. samueli (Del Hoyo et al., 1997). Differences in beak apparatus are one of the most prevalent variations observed within the subspecies. Throughout the paper an examination of evolutionary forces will explain the changes that have occurred in the beak apparatus of the red-tailed black-cockatoo.


Male red-tailed black-cockatoos are black with areas of red on the underside of their tails except on the two central feathers. They have an upright, backward-sloping crest and dark grey bills and feet. Females are brownish black with areas of yellow on their head, shoulders, and the underside of their tales. Their bills are cream colored, and their feet are dark grey. The actual size of the cockatoo ranges from 50-65 cm and 570-870 g (Del Hoyo et al., 1997). Calls of the cockatoo are loud, harsh, and can be heard from a distance (Higgins, 1997).

Red-tailed black-cockatoos usually form a lifelong bond with their mating partner (Del Hoyo et al., 1997). They typically nest in large hollows of eucalyptus trees where they rear their young, generally one egg per clutch. Parental care is shared between the two mates; however, the female does most of the incubating and the male does most of the feeding (Higgins, 1997).

Subspecies Variations

Subspecies of red-tailed black-cockatoos differ in regards to their body size, beak structure and size, and the coloration of females. The variation in beaks is due to the presence or absence of a groove at the tip of the upper maxilla and the shape of the cutting edge on the lower mandible (Higgins, 1997).

How to Cite this Page

MLA Citation:
"Red Tailed Black Cockatoo." 15 Dec 2019

Need Writing Help?

Get feedback on grammar, clarity, concision and logic instantly.

Check your paper »

The Red Indians And The Black Indians Essay

- In the history of United States, the red Indians and the Black peoples own a very unique and wondrous extent. They both suffered from a course of collective tragedy over nineteenth century. They have been misrepresented, stereotyped and simplified over time. Their stories cannot be simply condensed into one master narrative of defeat and decimation. To understand what really happened to them, we need to look at various historic pieces on the lives of many Indians, Blacks and Whites- that contributed to these multi-faceted stories....   [tags: Black people, Slavery in the United States]

Research Papers
1208 words (3.5 pages)

The Wedge-Tailed Eagle (Aquila Audax) Essay

- The Wedge-tailed eagle (Aquila audax) is the largest Australian bird of prey 1, 2, 3, 5 . One of the most characteristic features of the Aquila audax is its long, wedge like tail1, 3, 5, 7 . They’re also identifiable by their narrow wings and distinctive shoulders when perched 1, 3, 5, 7. The beak is yellowish-grey, the eye brown to dark brown, and the feet off-white. The wedge-tailed Eagle also has feathering all the way to the toe1, 2, 3,5,7. The adult Aquila audax is largely dark brownish-black, excluding the reddish-brown hackles on the back of the neck and a narrow, speckled grey-brown band across the upper wing1, 3, 5 ....   [tags: birds of prey, Australia]

Research Papers
1150 words (3.3 pages)

Gothic Horror in Susan Hill's The Woman in Black and H.G. Wells' The Red Room

- Gothic Horror in Susan Hill's The Woman in Black and H.G. Wells' The Red Room As with all things, the gothic horror genre of literature did not begin at one definable point, but evolved gradually. Gothic horror evolved out of gothic fiction (as opposed to classical fiction, for example the novels of Jane Austen), before establishing itself as a genre in its own right. However, many literary scholars and critics would point to "The Castle of Otranto", written by Horace Walpole and first published in 1764, as the first true gothic horror novel, containing as it does many of the clichs prevalent throughout the genre....   [tags: Wells Red Room Hill Woman Black Essays]

Research Papers
1983 words (5.7 pages)

Management Of Pacific Douglas-Fir Stands To Maintain Black-Tailed Deer Populations

- Management Of Pacific Douglas-Fir Stands To Maintain Black-Tailed Deer Populations Introduction Within the Pacific Northwest region of the United States, intensive, even-aged silviculture has simplified the structure and species composition of native forest stands. Within the range of the coastal Pacific Douglas-fir (Pseudotsuga menziesii), old-growth forests presently cover only 13 percent of the region; 60 percent of these remnants occur in patches less than 40 hectares in size. In this region, total land area consisting of old-growth forest before extensive logging has been estimated at 60-90 percent (Williams and Marcot 1991)....   [tags: Environment Animals Environmental Essays]

Free Essays
3080 words (8.8 pages)

Essay on Symbolism in The Masque of the Red Death

- Edgar Allen Poe, in the short story “The Masque of the Red Death”, shows how people may try to outsmart death and surpass it, but in the end they will die since death is inevitable. He reveals this in the book by showing all the people closed up in the abbey that belongs to Prince Prospero. They are trying to escape the “Red Death” and think that they can escape the death by hiding away in the abbey. They manage to stay safe for six months but in the end they all die after the stroke of midnight during the masquerade ball Prince Prospero puts on from the Red Death itself which appears after midnight and leaves no survivors in the end....   [tags: Masque of the Red Death Essays]

Research Papers
1690 words (4.8 pages)

Benefits of the Red Drum Fishery Essay

- Red Drum populations along the east coast and gulf coast of the United States, have drastically diminished over the past thirty years. The cause of the drop in numbers of this beautiful fish is primarily due to the overfishing from both recreational and commercial fishermen. Federal and State governments have implemented measures in to prevent this fish from being targeted, and to make sure that the population numbers increase. Not only is this fish important for the fisheries in which they thrive, but they also contribute to the biodiversity of a number of different ecosystems....   [tags: Red Drum Populations]

Free Essays
2186 words (6.2 pages)

Essay on The Effect of Red on Performance Attainment

- The teacher passes back the last graded papers, and the students wait patiently for their grades. A student on the first row is the first to receive his paper. As he looks at his paper, the smile disappears from his face, on his paper there are a lot of red pen marks. It does not matter if the comments are positive or negative, all he can focus is on is the red pen markings. Thoughts of failure invade his mind as he analyzes his mistakes. Red pens should be banned from the classroom because it of the psychological and biological repercussions it can cause; and another ink color should be used instead....   [tags: children, learning, red ink pens]

Research Papers
1121 words (3.2 pages)

The Masque Of The Red Death Essay

- Masquerade In the short story “The Masque of the Red Death” written by Edgar Allan Poe, death and color are portrayed as a narrative meaning. Edgar Allan Poe writes about death as an actual entity that lurks his way through the last masquerade of the night. In the short story “The Masque of the Red Death” there are seven colored rooms that each have their own distinct color that describe what stage of life the followers of Prince Prospero were facing. The symbolism in the rooms of the castle “The Masque of the Red Death” has a unique meaning; furthermore, the symbols used in the story is the most important part in the story....   [tags: Edgar Allan Poe, The Masque of the Red Death]

Research Papers
1001 words (2.9 pages)

Essay about White Tailed Deer

- White tailed deer (Odocoileus virginianus) are one of the most common species of mammals seen in North America, the most common of large animals actually. The last official count of deer in the USA and Canada was done in 1982, at which time 15000000 were found at an average of 3 deer in every square kilometer. The deer are very much native and were hunted even by Native Americans. You may have even seen this species yourself. Some of the most common places to find them are in your own backyard, in parks, or even dazed at headlights in the middle of Winton Road....   [tags: essays research papers]

Free Essays
422 words (1.2 pages)

black and red drum Essay

- Have you ever been fishing before. Not fishing based on lucky casts with worms or a bobber but fishing based on knowledge of what the fish do under the waves. I’ve been interested in fishing since the beginning of my time here on earth. Fish fascinate me, and catching them on rod and reel excites my inner primal being. I chose this topic to get into the mind of the fish I aim to catch. I already know much about my quarry. I know that Red Drum come in from the ocean to spawn in salt water back bays....   [tags: essays research papers fc]

Free Essays
2190 words (6.3 pages)

Related Searches

Figure 1 illustrates the variations observed in four of the five subspecies beaks. The significance of these variations will be addressed in later sections.

C.b. banksii is the largest of the subspecies. The groove in the upper maxilla is usually very small or absent, and the cutting edge of the lower mandible is slightly rounded and concave. C.b. macrorohynchus has the largest beak in the subspecies and a relatively large body size. Characteristics of the beak include a large distinct groove in the upper maxilla with a rounded and concave cutting edge on the lower mandible. C.b. naso is smaller with a more spherical beak. The groove in the upper maxilla may be large or completely absent, and the cutting edge on the lower mandible is concave. C.b. graptogyne is the smallest of the subspecies. The upper maxilla may have a small or absent groove, and the cutting edge of the lower mandible is sharply defined. C.b. samueli is close in size to C.b. naso. The cutting edge of the lower mandible is flat, and the groove in the upper maxilla is small or absent (Higgins, 1997).

Different characteristics in the bill and morphology, as well as diet and use of foraging substrates, suggest that regional differences in food sources have had an evolutionary impact on the species and subspecies of the red-tailed black-cockatoo (Franklin et al., 2000).

Species Distribution

Australasia is a region that has a limited number of total bird species probably as a result of the following factors: (1) The large number of islands which tend to have fewer species than continental regions; (2) The relatively small land mass as opposed to other avifaunal regions; and (3) The arid climate (Podulka et al., 2004).

Granivores, or seed eaters, account for 20 percent of the land bird species in Australia including red tailed black-cockatoos (Franklin et al., 2000). The granivorous red-tailed black-cockatoos can be further divided into 1 of 2 groups: terrestrial, those that feed on the ground; and arboreal, those that feed in trees. Terrestrial granivores are most abundant in inland northern Australia and the semiarid zone, particularly the north-west. Arboreal granivores are most prominent in areas of higher rainfall like the coastal and sub coastal regions (Franklin et al., 2000).

Consequently, the subspecies of red-tailed black-cockatoos are distributed throughout the continent of Australia according to their foraging mode. C. b. banksii is found predominately in forests of tropical northern Australia. C.b. macrorhynchus inhabit woodland of eastern Australia. C.b. naso and C.b. graptogyne are found in eucalypt forests of southwest and southeast Australia. C.b. samueli, the terrestrial forager of the five, inhabits the semi-arid inland of central Australia (Del Hoyo et al., 1997).

Evolution of Available Food Sources

The separation of Australia from Gondwana had a significant impact on the food sources of the red-tailed black-cockatoo. Australia’s original biota consisted of forests dominated by gymnosperms: conifers, araucarias, and podocarps whose seeds are not enclosed in an ovary (Pyne, 1991). However, the continental shift is perhaps responsible for the stimulation of angiosperms, plants whose seeds are enclosed in an ovary (Pyne, 1991). Retrieving seeds from gymnosperms did not require red-tailed black-cockatoos to have specialized morphological traits but would require changes for feeding on angiosperms.

The northern movement of Australia into the tropics stimulated a dramatic change in climate. Increased aridity and high temperatures had an extreme impact on the plant species present. As a result of the change in climate, the continent began to dry and fire became much more prevalent (White, 1994). Those plants that survived the climate change evolved into sclerophylls, plants with small tough leaves that resist transpiration of water. In order to protect their seeds from drying and burning, plant species developed thick-walled woody fruits characteristic of fire-adapted serotinous shrubs and trees (Higgins, 1997). Sclerophylls eventually permeated every ecological niche in Australia (Pyne, 1991). Consequently, the feeding apparatus of the red-tailed black-cockatoo was affected by the change in food sources resulting in two distinct styles of beaks.

Beak Apparatus

The conventional configuration of a bird’s beak allows for two major motions: the lowering of the mandible and the raising of the maxilla (Homberger, 2003). By utilizing particular muscles Psittaciformes are able to bring together the tips of the upper and lower beak. They meet when the maxilla is depressed and the mandible is lowered allowing Psittaciformes to grasp objects in their beak (Homberger, 2003). Detailed descriptions of the beak movements are illustrated in Figure 2.

The design of the illustrated beak prevents caudo-rostral, back and forth movement, and medio-lateral, side-to-side movement (Homberger, 2003).

Evolution of the Beak Apparatus

The beak apparatus of certain subspecies of the red-tailed black-cockatoo has diverged from the conventional configuration of Figure 2 allowing for side-to-side movement. This observed change is thought to be an adaptation for eating seeds contained in hard, woody nuts that must be removed via cutting instead of by compression (Homberger, 2003). Choreographed movements of muscles result in transverse movement when the beak is closing which simulates a cutting motion. The motion of the jaw is very similar to that seen in ruminants (Homberger, 2003).

There are two basic types of beaks within the Psittaciformes, the psittacid and calyptorhynchid. Psittacid type beaks are generally found in ground feeders, i.e. C.b samueli, and do not allow transverse motions. The inside of the maxilla has a characteristic notch and rough texture used for manipulating food, and the mandible has a broad transverse cutting edge (Homberger, 2003). Psittacid type beaks are efficient at shelling seeds intra-orally without use of a foot. Seeds are shelled by positioning them against the rough notch of the maxilla and cornering them there with the transverse edge of the mandible. Before shelling the seed the weakest area of the seed is located decreasing the amount of force that needs to be exerted (Homberger, 2003). The use of the tongue in positioning food is illustrated in Figure 3. Since there is no lateral motion of the beak, the entire force generated by the jaw muscles is focused on biting force. This makes the psittacid type beak extremely effective at removing seeds from shells with weak points, but ineffective at removing seeds from within lignified thick shells (Homberger, 2003).

The calyptorhynchid type beak is usually found in arboreal feeding species and does allow for transverse movement of the jaw. The internal surface of the maxilla is smooth and typically has no apparent notch. The transverse cutting edge of the mandible is emarginated and V-shaped creating sharp corners on the lower jaw. It is necessary for cockatoos with calyptorhynchid type beaks to use their foot when positioning food. Seeds are held against the transverse cutting edge of the lower beak which aligns with the maxilla during transverse movement creating a cutting motion (Homberger, 2003). Instead of using sheer force to shell seeds, cockatoos with calyptorhynchid type beaks cut open shells by using side-to-side motions and their transverse cutting edge.


Red-tailed black-cockatoos with a calyptorhynchid type beak feed on seeds enclosed in fibrous-woody, thick-walled shells such as Eucalyptus, Allocasuarina, Banksia, and Hakea (Cooper, 2000). Eucalyptus is typically favored among the subspecies of arboreal feeding red-tailed black-cockatoos.

Red-tailed black-cockatoos that have a psittacid type beak typically feed on seeds from shrubs, grasses, and fruits of trees (Homberger, 2003). The terrestrial feeding subspecies of red-tailed black-cockatoo, C.b. samueli, favors a diet of burrs and hard seeds, i.e. Emex and Erodium.


The metabolic requirements of red-tailed black-cockatoos may also influence their distribution, choice of diet, and the evolution of their bills. A study conducted by Cooper et al. (2002) determined the basal metabolic rate (BMR) at a thermo neutral temperature for inland and forest red-tailed black-cockatoos. The evaporative water loss (EWL) was also determined due to its implications in their distribution and habitat. Programs were used to record O2, CO2, and dew point data collected during the experiment and to calculate the rates of O2 consumption, CO2 production and EWL (Cooper et al., 2002).

The basal metabolic rate of inland red-tailed black-cockatoos was found to be 0.62 +/- 0.13 mL O2 g -1 h-1 and 1.11+/- 0.13 mL O2 g -1 h-1 for the forest red-tailed black-cockatoo. The EWL of the forest red-tailed black-cockatoo was 0.44+/-0.07 mg g-1 h-1 and 0.89+/-0.16 mg g-1 h-1 for the inland red-tailed black-cockatoo (Cooper et al., 2002). It is beneficial for species that inhabit arid habitats to minimize energetic requirements and metabolic heat production (Cooper et al., 2002). Since the inland red-tailed black-cockatoo live in an arid environment it is logical that they have a lower BMR than forest red-tailed black-cockatoos, which are found in less arid environments.

Energy Requirements

In order to meet their energy requirements the cockatoos must create a balance between how much energy they spend obtaining food and how much energy they gain. Often a greater amount of energy is expended on a certain food than would be on another, but the energy return is greater. For example, forest red-tailed black-cockatoos can recover a seed from Eucalyptus marginata nut in almost 12 seconds while it can take 2.45 minutes to recover a seed from Corymbia calophylla, but the energy return is greater for C. calophylla which justifies the extra time spent to retrieve the seed (Johnstone and Kirkby, 1999).

The relationship between available energy and the amount of time it takes to acquire the energy is derived from Tables 1 and 2. Fewer nuts, cones, and/or seeds of the Eucalyptus marginata, Corymbia calophylla, and Banksi attenuata are needed to meet the energy requirement of the forest red-tailed black-cockatoo (Table 1). It takes slightly longer to acquire the energy from a Corymbia calophylla nut than it does from the Eucalyptus marginata, yet the energy return is much faster than the other nuts listed (Table 2).

These results show that the longer time required to open Corymbia calophylla nuts by forest red-tailed black-cockatoos is compensated for by their high energy return (Cooper et al., 2002). Similarly, inland red-tailed black-cockatoos are able to meet their energy requirements by feeding on E. australis seeds.

Considering the variations observed amid the five subspecies of red-tailed black-cockatoo, the differences in beak apparatus is perhaps the most significant. The exact sequence of events that led to the differentiation in beaks is not precisely known, nor is it definite how all of the previously discussed issues relate to one another. However, it is clear that the combination of changing food sources, availability of food sources, metabolism, and energy requirements are of the main reason for variations of the beak apparatus in red-tailed black-cockatoos.

Literature Cited

Cooper, C. 2000. Food manipulation by Southwest Australian cockatoos. Eclectus. 8:3

Cooper, C.E., Wither, P.C., Mawson, P.R., Bradshaw, S.D., Prince, J., Robertson, H. 2002. Metabolic ecology of the cockatoos in the south-west of Western Australia. Australian Journal of Zoology. 50: 67-76

Del Hoyo, J., Elliot, A., Sargatal, J. 1997. Handbook of the Birds of the World. Vol. 4. Sandgrouse to Cuckoos. Lynx Edicions, Barcelona.

Franklin, D.C., Woinarski, J.C.Z., Noske, R.A. 2000. Geographical patterning of species richness among granivorous birds in Australia. Journal of Biogeography 27: 820-842.

Higgins, P.J. 1997. Handbook of Australia, New Zealand, and Antarctic Birds.
4: 40-51.

Homberger, D.G. 2003. The comparative biomechanics of a predator-prey relationship: The adaptive morphologies of the feeding apparatus of Australian Black-Cockatoos and their foods as a basis for the reconstruction of the evolutionary history of the Psittaciformes. In Vertebrate Biomechanics and Evolution, eds. Bels, V.L., Gasc, J.P., Casinos, A, pp. 203-228. BIOS Scientific Publishers Ltd, Oxford.

Johnstone, R.E., and Kirkby, T. 1999. Food of the forest red-tailed black cockatoo. Calyptorhnchus banksii naso in southwest western Australia. Western Australian Naturalist. 22: 167-177.

Podulka, S., Rohrbaugh, R.W., Bonney, R. 2004. Handbook of Bird Biology. Princenton University Press.

Pyne, S.J. 1991. Burning bush: a fire history of Australia. New York: Henry Holt and Company.

White, M.E. 1994. After the greening: the browning of Australia. Kangaroo Press.
Return to