Restricted to New Britain, in the Bismarck Archipelago, eastern Papua New Guinea, the blue-eyed cockatoo (Cacatua ophthalmica) is one of the least-known cockatoos, both in the wild and in captivity. Reported occurrences on neighboring New Ireland apparently refer to birds taken there from New Britain, where they are commonly kept or traded as pets and regularly offered for sale at markets in Rabaul.
Taking its name from the bright blue skin surrounding its eye, this species measures approximately 193/4 inches (50 centimeters) in length and superficially resembles the familiar sulphur-crested cockatoo (C. galerita), to which it is closely related. At one time, these two species were considered conspecific.
The most prominent difference is in the crest. C. ophthalmica has a backward-curving crest of broad yellow feathers bordered anteriorly by elongated white crown feathers. For further description of the distinguishing features, please refer to my Parrots of the World: An Identification Guide (Princeton University Press, 2006).
The Blue-Eyed Cockatoo In Its Native Land
Our lack of information about the habits of these splendid cockatoos is due primarily to infrequent visits to New Britain by trained observers rather than to any scarcity of birds. In the 1960s, they were commonly found in rain forest throughout the lowlands and foothills up to about 3,280 feet (1,000 meters), becoming rare and locally dispersed at higher altitudes. Field surveys undertaken between December 1998 and April 1999 at two study sites along the east coast provided more precise estimates of abundance and a better understanding of habitat preferences.
At these study sites, observers encountered cockatoos only in forested areas, with counts of up to 73 birds per square kilometer in primary forest and selectively logged forest. The birds?seemed to prefer those habitats over forest gardens or secondary forest, where counts were less than 28 birds per square kilometer.
Similar habitat preferences and levels of abundance were noted elsewhere on the island. A cautious extrapolation of population figures from the study sites was applied to New Britain as a whole, and this produced an estimate of 115,000 total birds. Land clearance resulted in some habitat loss, so presumably those numbers have declined. Nevertheless, the absence of large-scale trapping and the preservation of extensive tracts of undisturbed forest keeps the species?numbers high.
These cockatoos spend most of their time in the canopy and are usually seen singly, in pairs or small parties flying above the treetops. The discordant call-notes invariably betray their presence well before they come into view. A flock of 40 birds was the largest group encountered during the 1998 to ?9 field surveys.
Corresponding to the birds?main bouts of foraging, peak activity levels for the blue-eyed cockatoo take place in the early morning and late afternoon. During these times, the birds are seen in the vicinity of villages. At midday they shelter amidst the canopy foliage.
They gather in flocks of 10 to 20 birds around dusk in tall trees for their pre-roost gatherings, engaging in aerobatics accompanied by constant screeching. On one occasion, a cockatoo was seen flying down a steep mountain slope, descending nearly 1,000 feet before turning and twisting, as if to reduce speed, and then disappearing into a forested canyon.
Compared to the familiar screeching notes of sulphur-crested cockatoos, observers find these cockatoos?calls more high-pitched, less raspy and more nasal. Recorded calls include a series of screams, each note terminating in a downward deflection, usually emitted while perched. A loud, nasal ?aah?was recorded at intervals of one to three seconds during flight. The flight comprises fluttering wingbeats interspersed with gliding.
Seeds, nuts, fruits, berries and probably insects and their larvae make up the blue eyed? diet. The bird procures these items in the treetops. Some individuals were observed in coconut palms feeding on both flowers and fruits. Feeding on Melanolepis fruits, wild figs and blossoms of Eucalyptus deglupta was also recorded.
Blue-eyed cockatoos nest in a hollow limb or hole, high off the ground in a forest tree. Ten of the 13 nests found during the 1998 to 99 survey were in trees in primary forest, and all nests were in large trees at heights between 42 3/4 and 164 feet (13 and 50 meters). Hollow entrances measured between 7 and 201/2 inches (18 and 52 centimeters) in length and between 51/2 and 15 inches (14 and 38 centimeters) in width.
The Blue Eye In Aviculture
Aviculturists in North America and Europe have successfully bred the blue-eyed cockatoo. In the mid-1980s, Sheldon Dingle was particularly successful with a pair held in his aviaries in Los Angeles, and he kindly provided me with some details of his experiences. The original breeding pair was probably wild-caught, because it was suspected that both birds were brought into the United States by an airline pilot who had worked extensively in Southeast-Asia and Papua New Guinea.
The pair was initially housed in an aviary that was 12-feet long by 4-feet wide by 8-feet high, with a covered shelter and a cement floor. The birds did not seem to like this aviary, and no courtship or nesting activities took place. The aviary was in a block of 12 flights, and it? possible that the pair was bothered by their neighbors.
After more than a year without any nesting activity, Dingle transferred the pair to a 4-foot square cage that was covered on the top, back and part of the way down the sides. He attached a nest box to the outside, and positioned the new cage away from his other aviaries. The cockatoos reacted positively to this change nearly immediately. They commenced courtship behavior, and the male became very aggressive. Prolonged copulation, often occurring twice a day, preceded egg-laying.
This pair? diet comprised of a standard large parrot seed mix dominated by safflower but with very little sunflower, and mixed with smaller seeds, including flax, millet and niger. Supplementary foods included soaked, sprouted sunflower seeds, seasonally available green foods, mainly chard and romaine lettuce, apples and corn-on-cob. Quantities of these supplementary foods were increased prior to and during nesting.
Made with 1- by 12-inch planks, the grandfather-clock type nest box was approximately 4 feet tall and about 12 inches square, with an entrance hole and perch about 10 inches down from the top.
The exterior was covered with 12 gauge, 1- by 3-inch wire mesh to prevent the birds from escaping if they chewed through the wood. A door was cut out at about 12 inches above the bottom of the box to enable access to the eggs. Clean pine shavings were tightly packed into the bottom of the nest box to a depth of about 12 inches, but the birds normally scraped down to the wooden floor, leaving only a small quantity of shavings to protect the eggs.
There was no discernible seasonality in nesting activities. Clutches normally comprised of two eggs, and incubation was undertaken solely by the female. Unlike her mate, she was quite docile and unperturbed by weekly inspections made through the access door.
The first few eggs laid were infertile, but fertile eggs came soon after. The female incubated closely. In the first fertile clutch, one chick hatched and was fed by the female until it was fully feathered. At that time, Dingle removed the chick for hand-rearing as a precaution against attacks by the aggressive male.
In subsequent clutches, the eggs were cracked or broken by the male who also ate the eggs on occasion. Dingle modified the nest box so that the eggs rolled through a hole in a concave false floor to collect in a well-padded basket. All eggs were artificially incubated, and the chicks hand-reared. This system proved successful and resulted in nearly 25 youngsters before the pair went to another breeder. The female died shortly after the move.
In Spain, Sergio Chaves received similar success with his pair of blue-eyed cockatoos, and he kindly provided some details of his experiences with these birds.
The breeding pair is housed in an aviary with an indoor shelter attached to an outdoor flight that is 241/4-feet (8 meters) long, 10-feet (3 meters) wide and 61/2 feet (2 meters) high. They receive Kaytee Exact Rainbow Chunky for large parrots supplemented with sunflower seeds, peanuts and walnuts and a mix of diced fresh fruits and vegetables, including oranges, apples, pears, carrots, corn, green peppers and green beans.
The hen lays a clutch of two eggs in the spring, and, on rare occasions, a second clutch of two eggs after the first clutch has been removed for artificial incubation and hand-rearing.
Chaves rears chicks with Kaytee Hand Feeding Formula for larger parrots. At 3 months old the chicks are fully feathered and at 4 months, the young birds are independent. Hand-reared birds become affectionate, inquisitive and active. They are less noisy and more active than Moluccan cockatoos (C. moluccensis) but not as active or nervous as the Western corella (C. pastinator).
I am somewhat apprehensive about the long-term viability of captive populations of blue-eyed cockatoos when virtually all offspring are being hand-reared. Parent-reared birds normally make more reliable breeders, and I would be more confident of the species preservation in aviculture if breeding pairs could be made up of parent-reared birds.
Papua New Guinea? strict conservation legislation prohibits commercial exports of wildlife, which makes it unlikely that we?l be able to augment the captive population with new lines from wild blue-eyed cockatoos. Also, while numbers in captivity remain fairly low, the genetic pool for breeding remains restricted, so every effort must be made to maximize successful breeding to ensure that this most interesting cockatoo can be maintained in collections.
For me, the blue-eyed cockatoo is almost synonymous with Chester Zoo, in northern England where I first encountered these birds. That institution has been particularly successful in breeding the species. The European Studbook for captive populations also is maintained at the zoo, thus enhancing the association between that institution and this species.
Since the first pair was brought to the zoo in 1966, 40 youngsters have been reared successfully, and nine of these were loaned to other collections to form the core of a coordinated international zoo breeding program.
Aviaries with indoor shelter measuring 121/4 by 121/4 by 121/4 feet (3.7 by 3.7 by 3.7 meters) house pairs. A connecting outdoor flight of similar dimensions is available to them, too. Wood shavings cover the concrete floor of the shelter and sand covers the outdoor flight? floor. Each aviary is arranged so that the occupants are in auditory, but not visual contact, with other cockatoos.
According to the Chester Zoo, there are no plans for the birds to go on public display.