Abstract
Within the dark recesses of a hollow log, life begins rather harshly for the crimsonrumped toucan. This bird hatches blind, naked, and helpless, and it will be close to seven weeks before it emerges to see the light of the jungle and use its wings for the first time. Within the confinement of this tiny hollow log, where the chamber may be only six inches in diameter, and sometimes in competition with as many as four other chicks, this grotesque-looking baby bird will develop its beautiful emerald plumage in readiness to show the world when it leaves its prison-like nest.
The family of toucans, which comprises about 40 species, also includes the smaller varieties of toucanets and aracaris. The crimson-rumped toucanet is one of the smallest species. It is approximately 12 inches long and is found in the sub-tropical zones of southwest Colombia and the Andes of Western Equador. Its plumage is generally green throughout, with a reddish-orange patch of feathers, for which it is named, at the base of the tail. They have a white enamel stripe at the base of their bills. Though both sexes are identical in color, the females do not have as long a bill as the males.
These toucanets use the cavity inside a dead palm tree for nesting. The entrance of the cavity is usually started by other birds, such as woodpeckers, which can penetrate the hard outer surface of the palm trunks. In captivity the aviculturist can start the hole. The Toucanets then enlarge these cavities by chipping out the soft center portion of the trunk. Such cavities may sometimes be over six feet deep inside with an entrance hole about two inches in diameter, thus enabling the Toucanets to squeeze through but keeping large predators from entering.
After completion of the nest, breeding takes place and the female will lay up to four small white eggs cushioned only by a small amount of sawdust in the bottom of the nest cavities. Both parents participate in incubation but the female spends most of the time on the nest. Due to lack of space, the tail of the bird is folded vertically against its back when inside the nest.
After an incubation period of 16 days the chicks hatch approximately a day apart, and the young are completely blind and naked. They are pink in color, but acquire a bluish tinge where the eyes and feathers will appear. Right after hatching, the young chicks display a very distinctive feature known as "heel pads" on the upper end of their tarsus. These heel pads are used as a means of support while the young birds are in the nest and also aids them in climbing up in the nest cavity to the exit hole during the last week of nesting. The heel pads start to slough off after the birds leave the nest, and by the time they become adults, the heel pads are completely gone.
About seven weeks after the chicks have hatched they will leave the nest log. They are dependent upon their parents for a few weeks until they are eating on their own. The parents will feed them a variety of fruits, but insects and parts of other baby birds and rodents are also used. All food is fed either regurgitated whole or partially digested, especially in the early stages of growth.
When leaving the nest log the young chicks will hop from limb to limb until the wing muscles are strengthened. They do not acquire the white enamel stripe at the base of their black bill until about two months of age.
Thus in one of the most unique ways in the avian world the young toucanets are transformed from helpless pink hatchlings to emerald beauties ready to start a new life for themselves.
The photographic technique used was to lower a Hasselblad camera vertically to a prearranged depth inside the log from the top which was removed. A tiny electronic flash was taped to the camera's side to enable it to enter the six inch diameter nest. Trial exposures were taken the first time so very little time was spent thereafter. This kept the disturbance to a minimum. The top of the log was replaced in its normal position when we finished.
The following is probably the first and only growth record ever recorded of any species in the toucan family. The keelbilled toucan will be my next project.