Abstract
The Choco Toucan (Rampbastos brevis) is a large, black toucan of the genus Ramphastos, whose main identifying characteristics are its bright, lemon yellow breast patch and its large, flamboyant bill, which is generally yellow on the upper mandible and black on the lower. The yellow and black colors meet each other diagonally.
The Choco Toucan is routinely confused with and misidentified as the Black-mandibled Toucan (R. ambiguus), to which it is remarkably similar in appearance. The Choco is also similar to the Swainson's Toucan (R. ambiguus suiainsonii), except in the latter form the black is replaced by chestnut brown in the lower mandible.
The Choco Toucan is noticeably smaller in size than both the Blackmandibled and Swainsorr's Toucans, and belongs to the channel-keel billed group of toucans. The Blackmandibled and Swainson's, on the other hand, are members of the smooth billed group of toucans. The Choco's bill is definitely keeled in shape and is very similar in form and size to the Keel-billed Toucan's beak (R. sulpburatus).
Since Black-mandibled Toucans do not currently exist in captivity in the United States, size comparisons between it and the Choco are not possible. The only positive means, therefore, of properly identifying the Choco Toucan is by its call. The Choco utilizes a series of croaks nearly identical in sound to the call of the Keel-billed Toucan. The Blackmandibled Toucan's call is composed of two or three high-pitched yelps reminiscent of the Swainson, Couvier, and Red-billed Toucan calls. The distinct difference in vocalizations is marked.
The geographic distribution of the Choco Toucan is the smallest of the large, black toucans. It is restricted to the Choco region of northern Colombia and the Pacific lowlands south to northwestern Ecuador. As such, the Choco is the only toucan found on the Pacific coast of South America, whose coast is characterized by increasingly dry desert conditions.
Choco Toucans were first imported into the United States in the early 1980s, and only in small numbers. Very few of these found their way to private or institutional collections, and there are probably less than two dozen pairs in the country at the present time.
Originally, eight birds were acquired at Walnut Acres Aviaries.* These were sexed as two males, one of which was lame, and six hens. The one good male was set up with a hen, two birds were transferred to other collections, and the remaining kept together in a holding flight. After several years and the suspicion that the "hens" had been missexed, some were resubmitted for surgical sexing. Of three birds, two were determined to be males and one female. A female was acquired from Sea World of Ohio, and the two pairs were set up in large outdoor flights measuring 12 by 13 feet, eight feet high.
In early July 1989, a pair, the female of which came from Ohio, was observed investigating their nest, a palm log four feet in length, which had been hollowed out to a depth of two feet. The pair began working at further hollowing out their nest, a necessary ingredient to pair bonding and the precursor to the onset of egg laying.
On July 14, 1989, two eggs had been laid, only one of which was to hatch on July 31. During the incubation period, the nest was only checked once and during the nestling period, checks were limited to every four to six days in order to minimize the disturbance to the parent birds. Nest disturbance may be a cause of nest abandonment and/or cannibalization of offspring, a not infrequent occurrence among the large, black toucans.
As the chick progressed, its begging vocalizations increased in volume, such that the chick could be monitored indirectly from outside the flight. However, had there been more than two chicks, monitoring progress in that indirect fashion would prove less than effective in keeping informed of the number of live chicks in the nest.
On September 18, 1989, the lone chick appeared at the nest entrance. For the next two days, the chick sat in the entrance and immediately retreated into the nest as soon as it observed an approaching human. By the 20th, he appeared more secure, and on the 21st it left the nest for its first flight. In the days following ~the fledging, the young Choco remained calm and did not panic fly even when people entered the flight to service the food and water.
The emerging Choco Toucan appeared very similar to the adult birds. Feather coloration was an exact replica. Only the eyeskin and beak showed juvenile characteristics. The eyeskin was quite pale and the yellow of the upper mandible was much paler as well. Further, the diagonal demarcation between the colors of the upper and lower mandible was not well defined as in adult birds. The young bird was approximately 20% smaller in body size, though no attempts to weigh the bird were made.
Throughout the nesting cycle, the Chocos' flight was serviced on a daily basis. Prior to the commencement of egg laying, and up to the date of hatching, the adult birds were offered a daily regimen of dry dog kibble (Science Diet Canine Maintenance), diced apples, canteloupe, papayas, and destemmed grapes. Live crickets were also offered during this time and, in fact, had been offered to the adults for several weeks prior to the onset of nesting activity as an enticement to breed. It is unknown whether the enticement worked or was merely coincidental to the reproductive activity.
Once the young Choco hatched, the diet was only slightly modified in that the dog kibble was offered soaked, fresh each day. The live crickets were continued and were readily consumed by the parents. Naturally, fresh water was available daily, and Vionate Vitamins were added to the fruit mix.
The entire nesting cycle progressed without incident. The adults never exhibited any aggressive behavior towards their offspring, which has remained with them through the end of the year. No further nesting activity was attempted by the adults during 1989, which may be due to the presence of their first offspring. Occasionally, large, black toucans will recycle for a second round if the first nest fails early, or the fledged offspring are immediately removed and kept out of earshot and eyesight. Chick removal was not effected with the Chocos in order to gather as much data as possible on their behavior both during and subsequent to the cycle. If all Chocos behave similarly, they may prove to be one of the more easily bred large Ramphastids.
• Walnut Acres Aviaries was located in Woodland Hills, California. As of early 1990, it was moved to Fallbrook, California and renamed Emerald Forest Bird Gardens. •