Capti~e Breeding and o« anagement u) Q) a> (J) «c of the (f) S c Jatllson's ornbill o U5 ~ I (Tockus jacksonii) c ..co """") by John Heston >. .D Los Angeles, California o(f) (5 ..c 0- "" - now that's an inter­ esting, descriptive term. Hearing of such an without some sort of visual reinforcement would only set my imagination free to concoct all kinds of weird, anatomical shapes and forms. Further, I'd bet the oot-so­ gullible residents of Missouri (the "show me" state) would, with suspi­ cious skepticism, dismiss the exist­ ence of such a creature as they might a "jackalope" or a "devil chicken. " A juvenile malejackson's hornbill with a southern yellow-billed hornbill. Well, indeed exist, and their appearance, as well as reproductive A young male with billalmost completely colored out. natural history, are probably more bizarre than most people may imagine. Hornbills are representative of the family Bucerotidae, within the order

A male near the nest box. Note the beginnings ofa plug at the nest entrance.

36 FebruaryIMarch 1989 , which also includes detritus, feces, and saliva. When com­ hoopoes and the more familiar king­ pleted, only a narrow, vertical slit fishers. The hornbill family alone remains through which she will consists of twelve genera, some forty­ receive sustenance from the male, and five species, various subspecies and to allow for the ejection of excre­ races, all of which are indigenous to ment. Primarily due to this aspect of the Old World. A variety of different their natural history, hornbills are forms are found in Africa, India, regarded as the most highly evolved throughout southeast Asia, and on of cavity-nesting . Once sealed many islands of the Indo-Australian within the nest, the hen remains long region. It's not surprising that the enough to lay and incubate her eggs, greatest number of subspecies and molt, and care for her young until races have evolved among island they have developed enough to be left groups such as the Philippines which, behind on their own. The total Understanding the Life by their very nature, facilitate geogra­ amount of time may range from 60 to phic isolation. 100 days, depending on the species. of Birds explains: Relative sizes range from the small Further, with a particular species, the Avian reproduction, Egg & Chick devel­ red-billed dwarf hornbill (Tockus number of young in a brood may also opment, Digestion, Feather structure & camurus) at 33 cm. (13 in.), to the influence the timing of the hen's color, Flight, Nutrition & Avian genetics. great Indian or concaved-casqued emergence. In the case of a large hornbill (Buceros bicornis) that can brood, the female may leave the nest Read cover to cover, or use as a reference be as large as 140 cm. (56 in.) from earlier due to spatial constraints, and book. Glossary, full index and original art. Hardbound. Over 300 pages. the tip of the bill to the end of the to form with the male, a division of tail. As their name implies, the most labor necessary to accommodate the Patrick G. Coyle Jr. is a breeder-educator prominent feature of their anatomy is increasing nutritional demands ofthe who presents useful infonnation in a style that is interesting and easy to understand. the bill, which is usually very large in young. relation to their overall body size. In Regardless of their preferred food $21.95, + $2 Shipping in U.S. some species the bill is topped by an type, these birds are superb oppor­ Calif. residents, add 6% tax. ornate casque that is situated cen­ tunists. Some species forage primarly trally along the median of the upper for fruit, while others mainly go after Summit Publications, Dept. W mandible. small . Still, other species may 11565 Sunset Knolls Rd Understandably, some people get be more generalized in their feeding lakeside, CA 92040 hornbills confused with toucans habits and, subsequently, hunt and which are definitely rivals with forage for both. respect to bill size, but the resem­ "Jeepers, creepers! Where'd you blance is only superficial.(Taxonomi­ get those peepers'" Upon first Major Mitchell's cally, toucans are more closely related observing one of these creatures, I'm Cockatoos to woodpeckers and are, therefore, fairly certain that's what I may have (Cacatua leadbeateri) categorically placed within the order mumbled to myself; however, if not, Piciformes.) Though the bill and it definitely sums up the inital effect. casque appear heavy and unwieldy, Unlike most birds, with the exception it's actually surprisingly light! In con­ of ratites (ostriches, rheas, etc.), horn­ struction, the outer shell is supported bills have human-like eyes accen­ by a network of "struts" composed tuated with long eyelashes that of cellular, sponge-like, bony tissue. express confidence and inquisitive As with most generalizations there intelligence. are always exceptions, and so is the Jackson's hornbills (Tockus case regarding the Malayan helmeted jacksonii), named for the British hornbill (Rhinoplax vigil). This explorer, naturalist, soldier and species has a casque of solid bone, author Sir Fredrick George Jackson which is known to be transformed (1860- I 938) - whew! - are indigen­ into carvings and other art forms by ous to the dryer regions of central east the humans that inhabit its range. Africa where they are known to feed Many species exhibit virtual mono­ predominantly on insects, other small morphism between sexes (male and animals, and some fruit. In the aviary, Jackson's hornbills female identical in appearance). In a full color limited edition print are very active, become quite tame, others, however, sexual differences by (dimorphisms) are evident in various and will usually get along well with degrees. other species ofbirds - except other EricPeake Hornbills nest within the hollow hornbills. Even though they seem to print size 20" x 15", sin: 950 cavities of trees and, with the excep­ have a less aggressive nature than 00 includes tax and tion of ground hornbills, the female many other species, more than one $60 shipping, U.S.A. becomes literally "walled" or pair of hornbills in the same aviary Order from "sealed" within the nest cavity after would be a most uncomfortable and, Corporate Environments the entrance is almost completely at times, nerve-racking situation. The 9200 Glenwood, #104, Overland, KS 66212 plugged with an amalgam of mud, pair that's predominantly referred to (913) 642-9756

afa WATCHBIRD 37 herein have a pair ofactively breeding and utilized as the result of carbohy­ Tarictic hornbills (Penelopedes drate metabolism - an adaptive phys­ panini) for neighbors. The maleJack­ iological mechanism exhibited by son's has never expressed aggressive many species ofanimals that are indi­ behavior towards the Tarictic male, genous to arid habitats. Still, in the even during a nesting cycle. On the aviary, a constant supply of fresh other hand, the Tarictic male will water is always present. rarely miss an opportunity to intimi­ The aviary these hornbills share date theJackson's and, indeed, does with many other birds is approxi­ ,.... so by flying into, or against, the wire mately 20 feet on each side and about TOP"AQUALITY - LOWEST PRICES partition between the flights like a 25 feet in height. A facility ofthis size cannonball. If this aggressive display is not absolutely necessary for breed­ ftru"'_~1 P.O. Box 15001 U IJ\,,-W Hamilton, OH 45015 is responded to at all, it's merely a ing this and many other species, but I CALL OR WRITE FOR BROCHURE token gesture mixed with an amalgam believe spacious accommodations TO ORDER CALL TOl.L FREE of curiosity and saving face ("Henry! may enhance reproductive success. Don't just sit there. Do something!") Further, a large area does allow for 1-800-222-3563 Obviously, the outcome ofplacing adequate exercise, permits a greater these two species together is a fore­ variety and number of popula­ WITH ~ C~D. gone conclusion. I have had a pair of tions to establish their respective 1.1 Jackson's co-exist peacefully with an territories, and provides each individ­ ALL OTHER CALLS 1-513-874-5881 actively breeding pair of plush­ ual with the opportunity to maintain KNOWN FOR QUALITY AND SERVICE crested jays (Cyanocorax chrysops), an adequate social force field ("their which would dive bomb them at the own space"). slightest provocation or whenever The flight, located on a hillside, is they ventured too near their nest or constructed of 4x4 inch square steel fledglings. The hornbills only reacted tubing framework, covered with Ixl with puzzled alarm and, even if it inch mesh weldwire fabric. Palos contradicted their curious nature, did Verdes stone has been set into the their best to remain clear of the jays' concrete foundation to form terraces business. An actively breeding pair of in the hillside and to enhance the Jackson's will have no problem co­ flight aesthetically. Tough, hardy existing with assorted quail, pigeons plants such as camelias, clivias, and doves, jays, mynahs, pheasants, rubber trees and bamboo are planted turacos, and many other species liberally throughout, and a contin­ where competition is not a problem. ually recycled and filtered stream Indifference seems to be the rule. flows through the center, for drinking The core oftheir daily diet consists and bathing. The sound of water of Wayne's bite-size kibble soaked in splashing over a series of "mini­ water (or a mixture of Aqua-Vitae), waterfalls" is a special ingredient chopped fruit, and both raw and enhancing the aviary in a natural way. cooked vegetables. They also receive The nest is best positioned high in hard-boiled egg, bird-of-prey diet a sheltered area of the flight to allow (Central Nebraska), and an assortment for as much security as possible, and of live foods such as crickets, meal­ perches have been placed in close worms, and even goldfish. When proximity to the entrance hole to pro­ feeding hard-boiled egg, it's a good vide a comfortable access for mud­ idea to crush them beyond recogni­ ding and feeding. In the wild, such tion so that the birds make no con­ accommodations are rare or non­ nection about what they are eating existent and probably impractical as and inadvertently learn to start eating they would only reduce nest security. Walnut Acres their own. Further, a 48-hour supply The nestbox is constructed, in part, of mynah pellets, dry dog kibble, and of a hollowed out 1/2 slice of a tree Aviaries raisins is always available. This mix­ trunk, with plywood on the back, breeding ture, which can be coated with Super top, and bottom. Overall dimensions Toucans, Toucanettes, Preen powder if necessary, is less sus­ are 18 in. in height, 18 in. wide, and Cockatoos, Macaws, ceptible to spoilage and, therefore, about 12 in. deep. The entrance hole Eclectus, African greys, works well as a backup or "fail-safe" is 3-1/2 in. in diameter, and placed Australian parakeets, measure in case other foods run out. just above center between the top and Parrots andFinches With hornbills, it should be empha­ bottom. sized that the only source ofmoisture Undoubtedly, the introduction of All Birds Closed Banded a nesting hen will receive is contained the nestbox was an essential catalyst Call or write for price list: Jerry Jennings within the food the male brings to the stimulating, almost overnight, nest. In captivity, foods containing behavior patterns that had not been (818) 884·5476 adequate moisture must be available previously observed. The female P.O. Box 6393, Woodland Hills, CA 91365 and offered regularly. Another source responded almost immediately by Visitors by appointment only. of moisture may be water retained sticking her head in the entrance and 38 February/March 1989 investigating its contents. Soon there­ after, she began pulling out pine needles, leaves, and other similar Robert Clipsham and Dale R. Thompson organic items that I placed inside for D.V.M. Avicultural Consultant nest bedding. It was soon obvious that all details about the nest environ­ ment were to be left to her. are pleased to announce As little as 15 days later, the first signs of "smearing" were found on the opening of some areas of the entrance hole. "Smearing" is the term I use to describe the cementing ofmud, feces, saliva, and fine detritus on the edges of the nest entrance. Some smearing may occur on other areas ofthe nest­ box as well, especially the top and sides. Interestingly, I have observed juveniles smearing mud along the edges of rails and other objects that ''MedidM ftW AtHadture offered no nest possibilities whatso­ ever. In this case, they were probably lJy AtHadturoli4ts" only exercising instinctual behavior so important in preparation for their role as adults later in life. Even though both sexes participate (805) 522-7543 in the entrance sealing process, at times it appears as though the male (818) 346-6234 may be the instigator. With the tip of his bill he will take an object such as a 5734 East Los Angeles Avenue leaf or chip of wood to the entrance Simi Valley, California 93063 and rapidly waggle his head from side to side - seemingly in attempt to Hours: Monday - Sunday by Appointment Only induce the female into taking an inter­ est. As the actual sealing of the entrance hole begins, there emerges a distinct pattern in its construction. A Pure, natural, and cleaned... glob of moist mud and detritus is finest cuttlebone available. taken to the entrance where it is small 6" - 7" • medium 7" - 1A" • jumbo 10" - 13" • mixed sizes deposited on the inside edges of the entrance with a fast, vibrating move­ ment of the bill, which is truly an animated trowel. Only some of the CUTTLEBONE.PLU~~ material will actually stick to become part of the plug but, growing bit by bit from the sides inward, the plug 5 Ibs. at $3.90 per lb. = $19.50 (M' , gradually increases in size until the 10 Ibs. at $3.00 per lb. = $30.00 Inlmum female can just barely squeeze All orders prepaid and shipped freight collectorder Sibs,) through. Also, it is not uncommon to see the female working from the FEATURING AUIC@""(_.I~ ~.I~ ~ inside while the male is working from LORY AND SOFTBILL DIETS without. Although they occasionally do, males are rarely observed actually entering the nest cavity. White urates Lory Life ~:~;: ~l~:~g Lory Life Nectar~:~;: ~~~:gg visible in the plug's matrix usually indicate the presence offeces utilized OTHER SPECIAL NECTAVORE DIETS AVAILABLE in construction. When older mem­ With the addition of fresh fruits these are complete diets. bers of a brood chip away the plug sufficiently to leave the nest, younger Wholesale and breeder siblings will instinctively reseal the (213) 776-6486 prices available. entrance with their own feces. Dick Schroeder: breeder of softbills. rare lories. and pet parrots At times when it became necessary to break into a nest, I always experi­ Cuttlebone Plus • 644 S. Isis Ave., Inglewood, CA 90301 enced an allergic reaction on my fore­ arm where it came in contact with the nest plug ingredients. I now believe it may be due to the remains of meal-

afa WATeRBIRD 39 worms in the feces, to which I sud­ safe· from predators, it becomes the crypsis instead of a "fortress" to denly developed an allergy several male's sole, undying purpose to con­ avoid predation. The average egg is years ago. tinuously provide his mate with suste­ 2.35 cm. (15/16 in.) in diameter and During the sealing process, the nance and chase invaders from the 3.75 cm. (1.5 in.) in length. Typically, female is frequently observed going nest territory. It is this aspect of the an egg of this species is elongated, in and out of the nest, carrying leaves hornbill's behavior that has gained a and fairly similar in shape and size to and other similar material to be used place in African folklore as a symbol that of a common ring-necked dove. as bedding. While doing so, she of fidelity. And fortunately, because Judging from the marked increase understandably behaves as though ofsuch beliefs, killing these birds has in food consumption inside the nest, she'd prefer not to be seen in close become a cultural taboo. incubation seems to last about 25 proximity to the nest most likely out The Jackson's, unlike many horn­ days. This figure coincides closely offear that her clandestine operation bills such as the Tarictic (Penelopedes with field studies that cite 24 days as may be discovered. Eventually, she panini), do not regurgitate many the average. Because the young ofthe will fill the nest to just below the bot­ pieces of food in succession per feed­ same clutch emerge from the nest at tom edge ofthe entrancr so that feces ing at the nest. Instead, the male takes different times - sometimes weeks and other trash may be easily ejected. his mate one item at a time, offering apart - and considering their relative In order to eliminate, the female and the food with the tip of his bill. In state of development when broken young literally back up to the hole captivity, I provide a convenient out artificially, I would conclude that with their tail feathers pointed up, perch for this purpose; however, from all eggs do not hatch simultaneously. place their cloacal opening in line, the standpoint of predation in the Instead they hatch days, and even up and eject their feces outward with wild, this may not be an intelligent to a week, apart. The chicks are altri­ considerable force as though under arrangement. In their natural habitat, tial (naked and virtually helpless at pressure. Distances of three to four the male characteristically clutches birth) and must depend on their feet aren't unusual. Since their repro­ the tree trunk below or around the mother, as well as their own instincts, ductive strategy requires they remain nest entrance with zygodactylous feet until they are able to deal with the in confinement for two to three (two toes forward and two toes back), more serious matters of life on their months, this instinctual matter of not exactly but much the same way own. During the time the female is good housekeeping is not simply for woodpeckers do. And, like wood­ sealed in the nest cavity she also comfort but, indeed, imperative to peckers, they will use their tail molts. In fact, by the time the clutch survival and reproductive success. feathers to prop themselves into posi­ is complete, the female will lose all During this period the pair also tion. Sometimes it's necessary for the flight and tail featers at once, but all engage in an interesting display of male to get the female's attention by are regenerated by the time she breaks courtship. In unison, they slowly waggling food in front of the nest herself from the nest. Since the hen begin to make "clucking" sounds. As entrance. Usually she is quick to would not be able to fly during this the clucking increases in volume and respond and, depending upon how time, she would most certainly be pitch, they simultaneously bow their hungry she is, will often make a doomed if the nest were invaded by a heads down, spread their rectrices squealing noise as she snatches the predator. Discarded feathers from her wide, and lift their wings spread­ food away. The young also do this molt are not only found in the nest eagle fashion. At the point where the when hungry. Several hungry, young bedding, but also become plastered in clucking noise begins to reach a cres­ chicks begging for food from within a matrix offeces and saliva within the cendo, it suddenly ceases. They may, the nest is best characterized by a periphery of the nest plug, probably or may not, face each other during high pitched chorus of "chirp-like" by young that reseal the new "nest the entire display which lasts approx­ noises that remind me of a "squeaky exit" after the female or older imately seven to ten seconds. The wheel:' After appetites of the female siblings have left. genus name Tockus is said to be and young have been satisfied, the Since space is bound to be a pre­ derived from the vocalizations of male will try and tempt them into mium in an arrangement such as this, these animals: "tok, tok, tok, .. ." taking one more morsel. Ifthey fail to like other long-tailed cavity nesters however, the vocalization oftheJack­ respond he eventually gives up and, such as Piciformes (toucans, aracaris, son's hornbill is, instead, very similar after tossing the morsel to the back of etc.), the hen and developing chicks to the clucking sound of a chicken. his throat, he'll gulp it down hornbill­ are able to conserve space by prop­ Vocal patterns vary considerably style. ping their tail feathers up in a vertical between different species of this Egg laying commences approxi­ position. Further, when really genus. mately six days after the female is pressed or threatened, they will Once courtship and mating are completely incarcerated and, accord­ instinctively face into a corner ofthe complete, and after the nest has been ing to data taken from field studies, a nest box, and "freeze" with their bill properly prepared, the female then clutch size of two to five eggs is and tail pointed upward, similar to enters the nest and begins to fulfill expected. In captivity two to four how a bittern would be found attain­ the next phase of the reproductive eggs is the range I've learned to ing crypsis among the reeds. process. This is when the nest expect. As is the case with other From my observations, there seems entrance is finally sealed so only a cavity-nesting birds, the eggs are solid to be a direct correlation between narrow vertical slit approximately 1/2 white, which is a characteristic most brood size and the overall time a inch wide remains. Later, examination likely due to the lack ofenvironmen­ female remains in the nest. Probably of the entrance plug indicates that tal pressures within the nest. As one due to spatial constraints, a large both the male and female share in the may expect, birds that nest in the brood will force the hen out of the final process. With the female com­ open generally produce mottled and nest sooner. Further, a large brood pletely sealed inside and hopefully pastel colored eggs that rely more on requires more food and, in turn, will 40 February/March 1989 February 26, 1989 9am-3pm Only $4 Admission Seniors $3 Kids under 12 Free

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afa WATCHBIRD 41 necessitate a division of labor This situation may be a good example receiving at least the necessary mini­ between her and the male in order to that illustrates the sometimes duality mum requirements during her stay in keep up with the ever increasing of nature. Specifically, the hornbills' the nest. nutritional demands of the young. instinctive tendancy to play with Later, three weeks after the female The usual time period for the hen to their food for prolonged periods may had been out in natural sunlight and remain in the nest is anywhere from be more than preparatory. It may also on a good diet, another x-ray was 65 to 85 days. In their natural habitat, be, in part, a strategy to provide the taken. When the two were compared, the overall nesting period has been opportunity for young fledglings to no difference in bone density was found to average 45 days. Even acquire food until they have devel­ detectable. With this information, Dr. though on one occasion I felt it nec­ oped their own hunting skills. Pitts concluded that even though the essary to break a hen out after 85 Sexual dimorphism in the young is x-rays could offer no absolute proof days, I have found the nesting cycle in not readily apparent but, if you learn that continual nesting was not detri­ captivity to last 73 days on the aver­ what to look for, sex can be deter­ mental, they did confirm that there age. When ready, the young will leave mined at the time they leave the nest. were no obvious, or easily detectable the nest anytime from '1. 5 to 22 days The male is usually larger and has a ill side effects either. after their mother. Ifthere is only one lighter area at the base of the bill. It Many of the young produced by young, it usually fledges in 15 to 18 will take approximately 45 days for a pairs I have been maintaining have days after the hen leaves, but if there male's bill to start turning the long since been traded off to other is more than one, as many as 22 days reddish-orange color, and around breeding programs including the San may pass until all young have fledged. nine months for it to completely Diego Wild Animal Park, where Mary When all young have emerged and color out. Sexual maturity is com­ Lehris was having great success as start to become accustomed to their plete just after one year and nesting well. Such trades have enabled us and new environment, both parents will can occur between the first and others to establish more unrelated continue feeding and will always second year. breeding pairs, and further serve to remain close at hand. Though the I have had the opportunity to strengthen the existing breeding male does assert some dominance observe a pair ofthese birds engage in projects. over the young, he usually does so by an inexhaustible marathon endeavor. Primarily due to their ability to fly, gently squeezing the fledgling's neck This pair began to recycle continually we earthbound humans associate with his bill if they pester him too throughout the year, and were birds with freedom. For a female much, or pick the wrong spot on seemingly unaffected by external con­ hornbill to give up freedom for 60­ which to perch. He has never demon­ ditions such as temperature and plus days would seem the antithesis. strated injudicious aggression or an photoperiodism. I became increas­ From the standpoint ofsurvival, how­ intention ofharming the young in any ingly concerned and began to ever, it makes perfect sense as her way. wonder how often could the female nesting behavior enhances nest secur­ When they leave the nest, the lay without detriment to her physi­ ity, and with it the promise of future young are about the size of an adult ology. She exhibited no outward evi­ successful generations, and that is female and, at a distance, may be vir­ dence of fatigue, poor health, or the point. tually indistinguishable. Even so, other signs of trouble. Pulling the Sadly, though, this ingenious result there are some differences. Their bill nest box seemed like an obvious of evolution may become increas­ is slightly shorter and greyish-black "knee-jerk" solution, but after some ingly useless. Habitat destruction and instead of jet black, and their eye consideration I decided against it the use ofdead and dying trees as fuel color is grey. It will take almost one because no important questions in poorer nations may render the year for their irises to turn brown. would be answered. hornbill's, and many other cavity They get around surprisingly well, Instead, I let her go to nest once nesters, mode of reproduction inef­ and learn quickly despite the almost more, but this time I had a plan. After fectual. They will simply have instantaneous environmental transi­ she had been in the nest for about 60 nowhere to reproduce. This brings to tion they undergo - so much so, they days I broke her out and took her to mind efforts conservation-minded can be removed from the flight in Dr. Clyd Pitts of the Studio City people have made towards cavity which they fledged the very day they Animal Hospital for x-rays, hopefully nesters such as the wood duck and emerge, and will do fine without spe­ to determine her bone density. Theo­ bluebird in this country. Perhaps, cialized care, except for providing retically, after egg production and considering what has been learned them with an obvious source of rec­ two months in the dark, she should from proven captive breeding suc­ ognizable food. be at her lowest ebb. The x-rays, even cesses, similar efforts may be a viable When it comes to obtaining food, with a broad variance factor, still solution (although hopefully a tem­ youngJackson's hornbills are aggres­ might help determine if the female is porary one) and may help to ensure sive and natural opportunists. They experiencing excessive stress, espe­ future generations of hornbills will are demanding beggars and won't cially considering such important fac­ continue to play their part in a hesitate stealing food from an un­ tors as the calcium-phosphate ratio balanced ecosystem. suspecting parent or sibling. As the and the interaction with vitamin 0-3. REFERENCES intended target is customarily pre­ The resulting x-rays indicated that her Burton. Dr. Maurice. and Burton, Robert, paring its meal by tossing and mani­ bone density appeared normal. editors. The International Wildlife Encyc­ pulating it at the end of its bill, the Again, considerable amount of cal­ lopedia, VIII (1969), 1004-1006. youngster will characteristically hop cium deficit must occur before detec­ Karmali, John. Birds of Africa. New York: Viking Press, 1980, 143-145. right over and snatch it away with a tion can be confirmed, and there Kemp, A.C. A Study ofthe Ecology, Behal'ior squeal. The victim seems unaffected, were no other obvious health prob­ and Systematics ofTockus Hornbi//s(Al'es: as though it were perfectly normal. lems either. Apparently she had been Bucerotidaej, 1976.• 42 February/March 1989