That Bird Blog – Bird Care and History for Pet Birds

Few birds actually live up to the reputations we assign them – owls, for example, have been shown to be less “wise” than most other species when it comes to learning from their mistakes. The ringdove, however, does indeed seem to possess the calm, peaceful demeanor that we have come to associate with doves (although those I kept as a boy begun their admittedly “soft” cooing at 4 AM, rendering my otherwise patient mother far from “calm”!). Kept in a mixed species aviary, even breeding pairs of ringdoves are quite tolerant of smaller birds.

When I began work at the Bronx Zoo, a primary focus of the Ornithology Department was the conservation of the pink pigeon, Nesoenas mayeri. Limited in distribution to the island of Mauritius, off the east coast of Africa, this spectacularly colored bird is highly endangered. It is here that the ringdove’s “accepting nature” came into play. Pigeons and doves feed their young with “crop milk”, a food partially formed from the lining of the mother bird’s crop. Commercial substitutes exist, but none approach the real thing.

In order to obtain as many eggs as possible from the small captive population, we pulled eggs from incubating female pink pigeons and placed them beneath brooding ringdoves (egg removal, within a specific time period, stimulates the female to lay another clutch). The female ringdoves were wonderful foster parents. They produced amazing quantities of crop milk to feed their unusual nestlings, which grew to almost twice the size of their foster moms before fledging. I shall not soon forget the sight of a female ringdove literally perched on the back of a huge nestling pink pigeon while feeding it! Birds raised by foster parents of other species often have problems in breeding with their own species when they mature – fortunately, the fostered pigeons went on to reproduce normally.

The ringdove makes a fine pet and is available in a wide variety of colors, including apricot, white and pied. It has an unusual captive history, and may actually be a mere variant of the wild African collared dove, S.roseogrisea, which was domesticated 2-3,000 years ago. Its actual status is unclear, however, as captives have likely hybridized with related species, such as the Eurasian collared dove and the red-eyed dove. Feral populations of ringdoves live in the USA (Florida, Los Angeles, San Francisco), Italy, Taiwan and England, usually to the delight of local residents.

An interesting perspective on the origins of the ringdove is provided at: http://www.internationaldovesociety.com/Articles/ringneck%20history.htm

Indian peafowl, often referred to as “peacocks” (in truth that name should be applied to males only) are one the earliest species to have been established in aviculture, and still among the most desired. Despite their great space requirements and the loud calls of the males (one community in a NYC suburb passed an ordinance requiring surgical “silencing” of pet males’ vocal cords!), they remain quite popular in this country.

A group of 60 or so has roamed the grounds of the Bronx Zoo for decades. Although equipped with well-developed powers of flight, the birds simply do not leave the zoo grounds. Perhaps it is the un-inviting Bronx streets that dissuade them – although such did not deter a huge saurus crane, but that story is for another time!

Wild turkeys also inhabit the forested areas of the zoo’s 265 acres. Some years ago I noticed that a young turkey, separated from its mother, had taken up with a brood of peafowl. He followed the female about as if she were his own mother, and roosted with the family at night. Turkeys and peafowl, despite hailing from very different parts of the world, are related (both are members of the order Galliformes) and share many traits.

As the bird matured, he began sparring with male peafowl as opposed to male turkeys. One day a visitor alerted me to a “murder” in progress – a male peafowl stood over the turkey, pummeling the prostate bird and drawing blood with his sharp leg spurs. The turkey was fully alert and turned out to be not badly hurt (when I rescued him, receiving a gash for my efforts), but had seemed paralyzed and unwilling to fight back.

An older bird keeper provided an explanation of this odd behavior – as do many animals, turkeys utilize a submissive posture when they have lost a battle, thereby ending hostilities without serious injury. The turkey had apparently lain flat on the ground in an attempt to give up, but this had only spurred his enemy to further aggression. Peafowl and turkeys are related enough for males to view each other as rivals – yet not so close as to recognize each other’s behavioral signals.

As for the turkey, the lesson seemed only to confuse him further – he soon found small children easier targets than peafowl, and began running them down during the breeding season! He eventually found a home among a group of domestic turkeys at a local nature center where, hopefully, he sorted out his identity crisis.

As mentioned in my recent article on this blog, providing pet birds with access to sunlight and fresh air is of great value to their well-being. A pair of yellow-fronted Amazon parrots, Amazona ochrocephala, kept at a research station on Tortuguero Island, Costa Rica, where I worked some years ago, seemed a perfect example of this. They spent their days climbing in 2 small trees and over the ropes stretched between them (their flight feathers were clipped). Active and inquisitive, they were in the peak of health and color. A large cage, door opened, hung in one of the trees. For a time, the birds’ owner had tried to herd them into the cage for the night, but had given up in the face of their stubborn refusal to cooperate.

One morning, we awoke to the gruesome discovery of a small pile of blood-spattered feathers below the birds’ roosting site – all that remained of the male. Tortuguero is home to a number of creatures, including ocelots, Leopardus pardalis, great horned owls, Bubo virginianus, and the unusual Linneaus’ false vampire bat, Vampyrum spectrum, that would be more than happy to snack on a plump parrot. Apparently, the dog that usually slept below the roost had gone “off duty”, and a nocturnal predator had made the most of the lapse in security. On the very next evening, with only the slightest of prodding, the female walked over into her cage and perched quietly while the door was secured – and, I’m told, she has done so each night since!

To read the first part of this article, click here.
In reproductive biology as well, the palm cockatoo breaks with its close relatives. The male’s breeding display is the group’s most complex – flying high above the ground towards his mate, he raises his spectacular crest, deepens his cheek patch color, and calls loudly. They are the only cockatoos to build stick nests within their nest cavities – perhaps as a precaution against flooding – and their young are unique in hatching without down and in having such a long (to 160 days) nestling period. Even after all that time, young palm cockatoos fly poorly upon leaving the nest and are fed by their parents for an additional 6 weeks.

Strictly protected by the governments of New Guinea and Australia (and listed on Appendix I of CITES, The Committee on International Trade in Endangered Species), palm cockatoos were relatively unknown in American aviculture until quite recently. In fact, zoos here did not pay much attention to Psittacines in general – intelligent and gregarious, they need lots of room, stimulation and appropriate social groups and thus are difficult to provide for. After observing flocks of military macaws, Asa militaris, and other species, in the wild, I came to regard parrots and their relatives, in terms of their captive needs, as the “primates of the bird world”. Those of you who keep them as pets are no doubt familiar with their curiosity, and are fortunate in having a wide range of helpful products from which to choose when looking to keep them happy.

In 1983 the US Fish and Wildlife Service confiscated a large group of palm cockatoos, and placed them with various zoos and qualified private individuals. I was working in the Bronx Zoo’s bird department at the time, and learned that I would be assisting in the hand rearing of two chicks. Given the rarity of this species in captivity, I was excited by the opportunity to perhaps contribute to our understanding of its captive husbandry. The group eventually did quite well, and gave rise to a good percentage of the individuals in this country today.

The two chicks were at first fed (via syringe) around the clock, and thus required attention at all hours of the night. This quickly gave rise to their names – “OT” and “MOT”, signifying “Overtime” and “More Overtime”! Their helplessness (and the fattened pay checks they engendered) endeared the birds to their keepers. With barely any down feathers, they were at first kept at quite warm temperatures (92 F or so) in an incubator. Feather growth increased from age 3 weeks, when the temperature was reduced to 85F, and was complete when the birds were approximately 3 months old. The chicks’ face-patch color was variable even during their first weeks of life, although I cannot say what the changes meant. In common with most healthy nestlings, their feeding reaction was quite strong and, oddly, accompanied by much head bobbing.

In those days, formulas for hand-rearing cockatoos were not standardized, and the various zoos involved in the project experimented quite a bit. A dilute mix of Pedialite, monkey chow, baby cereal and fruit was common to most diets, and worked well (although not without some digestive upset). Today, both zoos and hobbyists have a number of fine products available, and hand-rearing success stories are more common. The chicks began pecking at solid food at 2 ½ – 3 months of age – I later learned that the timing of this milestones varies greatly among palm cockatoo chicks. Supplemental formula was given until the birds were approximately 4 months old and gaining weight consistently. They were later transferred to the World of Birds building, where their exhibit remains a major attraction.

I am happy to say that we learned quite a bit that has been of use to other bird keepers, hobbyists and their charges, and helped establish this magnificent species soundly in North American zoos and private collections.

Cockatoos and parrots are at once fascinating and challenging as pets – please share your own stories and forward any questions you might have.

You can see a video of a palm cockatoo at the Bronx Zoo (perhaps OT or MOT) below:

More information about the group of confiscated birds I referred to, and concerning parrot conservation in general, is available at:
www.nationalzoo.si.edu/publications/ZooGoer/2006/6/parriotsandprofits.cfm

Thank you. Until next time, Frank

It is not easy for a single species to stand out among a group of birds as spectacular as the cockatoos, but the striking palm cockatoo does so quite handily. At nearly 30 inches in length and with a 30-inch wingspan, this giant among cockatoos approaches the hyacinth macaw, Andorhynchus hyacinthus, the largest of the world’s 350+ species of parrot-like birds, in size. Its jet black feathers are set off by powdery gray down and highlighted by brilliant red cheek patches. Adding to the air of imposing size, the head is topped by a crest of long feathers and the beak is massive. Today I would like to tell you about my involvement with the first large group of palm cockatoos brought into this country and to discuss some of this magnificent creature’s unique characteristics.

But first, if I may, a bit more about what distinguishes this bird from the approximately 20 other species belonging to the family Cacatuidae, the cockatoos (all of which are members of the order Psittaciformes, along with parrots, lories and macaws). Palm cockatoos, also known as black palm cockatoos or goliath aratoos, are the only tropical rain forest-adapted members of their family — the rest being more at home in dry, often sparsely vegetative habitats. They are native to northern Australia’s Cape York Peninsula, New Guinea, Aru Island and smaller neighboring islands. Three subspecies have been identified, with New Guinea’s P. a. goliath being the largest.

Although this bird is unique among cockatoos in many ways, perhaps its most distinguishing feature is tool use — a phenomenon quite rare among birds in general. Most likely as an adaptation to a thickly forested habitat where sound travels poorly, palm cockatoos beat sticks and large nuts against hollow trees when communicating with others of their kind. This behavior, known as “drumming”, is repeated anywhere from 2 to over 100 times, and creates quite a racket. In fact, “palms” seem prone to odd modes of self-expression — when frightened, rather than hissing in typical cockatoo fashion, they stamp their feet!

Palm cockatoos are also unusual in possessing bare patches on the cheeks. The skin on these patches varies in color from dull red to bright crimson, depending on the bird’s mood, stress level, health and other factors of which we are as yet unaware. The face patch can also be covered with feathers during communication displays. The maxillary, or upper beak, is twice the size of that of its largest relative (its genus name, Probosciger, alludes to the beak). Extraordinarily powerful, this impressive structure assists the bird in securing its diet of large nuts (in captivity, even Brazil nuts pose no problem), seeds, fruits and leaf buds. The lower beak meets the upper only at the tip, leaving the mouth always slightly open. Unlike other cockatoos, which forage in large flocks, “palms” feed singly, in pairs, or in groups of up to 7 in number. Pairs return to their territories in the evening, but roost separately.

To read the rest of this article, click here.