Toucans are a New World family consisting of five genera and forty species of the family Ramphastidae. They can be found in the dense tropical jungles of the Amazon Basin and adjacent areas, and their name stems from ‘tucano’ given in the language of the Tupi Indians of Brazil.
Description
They vary from 30 to 60cm (12 to 24in) in length, but in some species, over half of this is made up by the bill, which is their most remarkable feature.
Toucans have strong legs with two toes pointing forwards and two back, typical of species of the order Piciformes. The two forward-pointing toes are fused at the base, and one toe is considerably larger and stronger than the other. The toucan is essentially arboreal, as the structure of its foot indicates, and it is adept at clambering among the canopy of large trees in search of food.
Toucans have either mainly black or green plumage with brightly coloured bands of red and yellow. All have bold patches of colour, particularly on the head and neck. Some are white with orange eye patches, others white with blue, and others yellow, red, or green.
They have a long bill. The colours of the face tend to accentuate the bill itself, making it appear even longer than it is.
Toco toucans are often depicted by artists and designers that they have become a symbol of the warm forests of tropical America. Think of Guinness or Fruit Loops, and you will be able to picture a toucan.
They are gregarious, noisy birds that are curious. They roam the forests in search of food, although the toucanets of the genus Aulacorhynchus make vertical migrations in the Andes synchronised with the different ripening times of fruit and berries.
In Central America, the chestnut-mandibled and keel-billed toucans have similar plumage and can only be told apart by their bills and sounds.
Bills
The bill of the toucan is its most recognisable feature. All toucans have huge, boldly coloured bills, which give them an out of balance appearance.
Many toucans have bold patches of yellow on the bill, and the exact location and extent of such colour is often an excellent way to identify them. Others may have black and white, maroon, yellow and red bills, while the keel-billed toucan has perhaps the most colourful bill of all birds, with all the colours of the rainbow apart from violet.
Although it looks heavy and despite the size of the bill, it is very light as it consists of a solid sheath on the outside, with a fine, honeycombed structure inside. The bills are masterpieces of engineering, being both strong and light.
The honeycomb of bone gives them the strongest form of construction for the lightest amount of weight.
The purpose of the toucan’s bills has been the subject of speculation among ornithologists. There have been many reasons for the shape and size put forward.
Some have suggested that it enables a toucan to reach out for otherwise unobtainable fruits. However, this is unlikely as many other birds manage to feed similarly without the same shape bill. Toucans use their bills when courting, fondling the bill of another, clapping their bills together or passing food to one another.
Other ornithologists proclaim that the bill of the toucan is a weapon with which it can defend its nest, while others suggest that the bill serves as a means of intimidating other birds to make them leave their nests so that the toucan can lay their eggs.
Another theory is that the bill gets rid of heat. Because the bill contains plenty of blood vessels with little insulation, the bill acts as a way of getting rid of excess heat from the bird’s body. This allows them to stay cool in the hottest temperatures.
The bill also varies in colour, even within a single species such as the keel-billed toucan. The bill of this bird consists of patches of almost any colour. Within the bill, the tongue reaches to the tip of the bill. The tongue is long, narrow and flattened.
Despite the internal strengthening of the thin, bony, supporting rods, toucans bills are fragile and may sometimes break. However, some manage to survive a long time with part of their bills missing.
The longest bill of a toucan is that of the male toco toucan, which accounts for 20cm of the bird’s total length of 66cm.
Whatever the truth, toucans do sometimes find their bills an encumbrance. Food, taken delicately in the tip, has to be thrown into the throat with an upwards head jerk.
Diet
The diet of toucans consists mainly of fruit but includes insects, an occasional lizard and eggs and nestlings of smaller birds. They eat lots of berries along with arillate seeds, small lizards and snakes, and flying termites.
Large items of food are torn by the bill while held with its foot against its perch.
Food is thrown back into the throat by an upward toss of the head from the end of the bill. This behaviour explains the bill’s length but not its thickness or bright colourations.
Birds are intimidated by the large bill and will often give up their nest and their young at the sight of a toucan coming to their nest. Even small hawks and American flycatchers will not stick around when they see the bill of a toucan coming their way.
For the most part, their diet consists of fruit, especially figs, but during the breeding season, many insects are also taken. Fruit is plucked with the tips of the mandibles and is thrown into the air, caught in the throat and then swallowed.
This is similar to how hornbills eat, even though they have evolved separately in two different parts of the world. Their method of feeding also indicates that the bill does not really serve the function of feeding as well as it should.
Behaviour
Toucans live and fly in small flocks, one after another, rather than in small bands, like parrots. They can be found in flocks of up to a dozen individuals but don’t act like a group. In flight, the big Ramphastos toucans beat their wings a number of times, then close them. As they lose altitude, immediately the black wings are spread, and the fall is changed into a short glide, followed by more wing beats that recover the lost altitude. The toucan traces an undulatory course from one treetop to another that is normally close by.
As one toucan flies away, another will follow, then another until the whole flock has left its perch.
Toucans prefer to remain high in trees, where they hop from branch to branch. They bathe in pools of rainwater in hollows high in trunks and limbs but are rarely ever seen at ground level. They offer food to their companions and will preen them with the tips of their long bills.
Toucans are playful birds and often engage in various games. After striking their bills together, two birds will clasp each other bills and push until once is forced backwards from the perch and retreats. Another individual may then cross bills with the winner, and the victor in this bout may be challenged again. Participants in a match reveal no sign of aggression. In another form of play, one toucan throws a fruit which another catches in the air, then throws it in a similar fashion to a third, who may throw it to a fourth member of the flock.
Toucans are often reported to sleep in holes, but this is only known to occur in the medium-sized aracaris and the Guiana toucanet.
Toucans will flock together and will fly noisily through the forests to and from their feeding grounds. The larger species fly with an alternate series of flaps of the wings and gliding, whereas the smaller birds fly more directly. In both cases, the flight silhouette is similar to that of a hornbill with a long bill and tail.
Voice
Toucans are not the nicest birds to listen to. They have been described as sounding like croaking frogs, mewing gulls, and even yelping puppies. They produce a rattling noise that seems to be mechanical.
Aracaris have higher-pitched, sharper notes, while the chestnut-mandibled toucan produces a nice melody. They sing mostly at nightfall, moving their heads up and down to make their songs.
Nesting
The large ramphastos toucans appear to nest frequently in holes resulting from the decay of tree trunks. If there are not many, then this may limit the number of breeding pairs. A favourable hole just wide enough for the adults to squeeze through may be used for many years. The hole may be only a few centimetres or up to 2 metres deep.
While they may enlarge the entrance and clear the debris from the nesting chamber, they do not excavate themselves. Nest height depends entirely on the size of the chosen hole and may vary from a few feet to near the top of a forest giant. A suitable cavity near the base of a trunk may tempt toucans closer to the ground than is usual. Smaller toucans often occupy woodpeckers holes, sometimes evicting the owners.
Hornbills may clean out and enlarge existing cavities and sometimes try to carve their own hole in soft, decaying wood. The nest chamber is never lined, but the 2-4 white eggs are laid upon wood chips or upon a bed of regurgitated seeds of various sizes, shapes and colours. As incubation proceeds, the amount of seeds becomes greater.
Both males and females share incubation and are impatient sitters, rarely remaining at their task for more than an hour and often leaving their eggs uncovered. During this period, the sitting bird often leaves the nest after short stints of incubation, but one bird always maintains an all-night vigil. They will not try to defend the eggs from intruders but will fly away.
After about 16 days of incubation, the young hatch blind and naked, with no trace of down on their pink skins. Looking like small woodpeckers, they have short bills with the lower mandible slightly longer than the upper. Around each ankle joint is a pad that protects it from abrasion from the rough floor.
The parents carry large billfulls of waste from the nest. Some will keep the nest clean such as the emerald toucanets, whereas keel-billed toucans will not clean out decaying seeds. The keel-billed toucan will take a few green leaves into the nests before removing them when they wither.
Nestlings are fed by both parents, with increasing quantities of fruit as they grow older, but they develop surprisingly slowly. The young toucans hatch naked, and the chicks develop very slowly, not even opening their eyes for three weeks. They then remain in the nest for at least another three weeks.
The feathers of the small toucanets do not begin to expand until they are four weeks old, and month-old Ramphastos nestlings are still largely naked. Both parents brood them, sometimes the male by night, as in woodpeckers.
When fully feathered, young toucans resemble their parents, but their bills are smaller and less coloured. Small toucanets may fly from the nest when 43 days old, but the larger Ramphastos toucans remain for about 50 days. Aracaris are led back to the nest to sleep with their parents, but others roost in foliage.
In the collard aracari, the nest may be invaded by several adults (or subadults) soon after the eggs have hatched. The extra birds may be the young of a previous brood. All the birds roost together in the hole, and all bring food for the developing young.
It is perhaps just as well that toucans have a tail structure that enables them to tuck it up out of the way over their backs. When roosting outside the safety of the nesting hole, they tuck their bills beneath the feathers of their backs and throw the tail upwards to cover it. While such communal hole-roosting is quite common among birds in many parts of the world, few species have the encumbrance of such a huge bill.
Genus
At first glance, it is easy to confuse toucans with hornbills, and in many ways, they are the equivalents of the Old World species. Toucans, like hornbills, have long, heavy-looking bills, long tails and rounded wings. Toucans are arboreal; they nest in tree holes and feed on fruit which they throw up into the air before swallowing it.
Unlike the hornbills, they have not developed a system of incubation in which the female is sealed up in the nest chamber.
The two families belong to different orders indicating that the relationship is distant or a case of convergent evolution.
Forty species of toucans form the family Ramphastidae, which is part of the great order Piciformes. This order includes woodpeckers, jacamars, puffbirds, barbets, and honeyguides. The family Ramphastidae is composed of five genera which are based on easily recognisable criteria.
Typical Toucans (Ramphastos)
The largest of the toucans, eight species form the genus Ramphastos or typical toucans. They can be found inhabiting lowland rain forests, where they make excursions into neighbouring clearings with scattered trees. They are rarely seen at altitudes of 1,500m (5,000ft) above sea level. Their plumage is mainly black or blackish, and their calls are heard as croaks and yelps.
The largest and most familiar toucan is the toco toucan of Brazil. It has the largest bill of any toucan and is the bird found in Guinness advertising and on the front of Froot Loops cereal.
- Channel-billed toucan (Ramphastos vitellinus)
- Choco toucan (Ramphastos brevis)
- Citron-throated toucan (Ramphastos citrolaemus)
- Green-billed toucan (Ramphastos dicolorus)
- Keel-billed toucan (Ramphastos sulfuratus)
- Toco Toucan (Ramphastos toco)
- White-throated toucan (Ramphastos tucanus)
- Yellow-throated toucan (Ramphastos ambiguus)
Toucanets (Selenidera)
The genus Selenidera is a group of six smaller birds known as toucanets. These species most closely resemble barbets, although they have larger bills. The colour pattern of toucanets are generally more complex than those of the larger species, and, unlike those birds, there are significant plumage differences between the sexes.
In the tawny-tufted toucan, for example, the sexes are quite different colours except for their bills which are orange-red, boldly spotted and marked with black.
The five species of toucanets belonging to the genus Selenidera can be found in rain forests at low altitudes from Honduras to northeast Argentina. Little is known of the habits of these small toucans.
- Golden-collared toucanet (Selenidera reinwardtil)
- Gould’s toucanet (Selenidera gouldii)
- Guianan toucanet (Selenidera piperivera)
- Spot-billed toucanet (Selenidera macurlirostris)
- Tawny-tufted toucanet
Mountain-toucans (Andigena)
The four members of the genus Andigena are commonly known as mountain-toucans. They are generally boldly marked in different colours. They are the least known of all the toucans, mainly due to their habitat. As their generic name Andigena implies, they inhabit the Andes from northwest Venezuela to Bolivia.
Although these and many other toucans are becoming rarer as their habitats are destroyed, many remain to be studied by naturalists if they can put up with the long months in hard to reach places.
- Black-billed mountain toucan (Andigena nigrirostris)
- Grey-breasted mountain toucan (Andigena hypoglauca)
- Hooded mountain toucan (Andigena cucullata)
- Plate-billed mountain toucan (Andigena laminirostris)
Aracaris (Pteroglossus)
The aracaris are a large group of medium-sized toucans which are placed in the genus Pteroglossus. They are generally black above and yellow below and are boldly marked with bands of different colours across the breast.
However, one of their most remarkable characteristics is that no matter what the colour or pattern of the bill, the shades combine to give an impression of bold serrations between the mandibles.
The fourteen species of aracaris are smaller and more slender than the other toucans. They are inhabitants of warm forests but rarely venture as high as 1,5000m. They have black or dusky green backs, crimson rumps and are usually black on the head and neck. Their predominantly yellow underparts are crossed by one or two bands of black or red. Their long bills are black and ivory white, wholly ivory white or mainly fiery red.
The calls of the better-known species are sharp and high-pitched for such large birds. They are the only toucans that make their homes in holes throughout the year.
- Black-necked aracari (Pteroglossus aracari)
- Brown-mandibled aracari (Pteroglossus mariae)
- Chestnut-eared aracari (Pteroglossus castanotis)
- Collared aracari (Pteroglossus torquatus)
- Curl-crested aracari (Pteroglossus beauharnaisii)
- Fiery-billed aracari (Pteroglossus frantzii)
- Green aracari (Pteroglossus viridis)
- Ivory-billed aracari (Pteroglossus azara)
- Lettered aracari (Pteroglossus inscriptus)
- Many-banded aracari (Pteroglossus pluricinctus)
- Pale-mandibled aracari (Pteroglossus erythropygius)
- Red-necked aracari (Pteroglossus bitorquatus)
- Saffron toucanet (Pteroglossus bailloni)
- Stripe-billed aracari (Pteroglossus sanguineus)
Green toucanets (Aulacorhynchus)
The fifth genus of the family contains the eleven species of the genus Aulacorhynchus. They are also known as green toucanets due to their colour. They inhabit the high Andes at an altitude of up to three thousand metres. As a result, these are the only migratory toucans, though even their migration is confined to a change in altitude only, as the birds move up and down according to the fruiting season of the trees.
Members of this genus are also the only toucans that attempt to rear two broods: the larger toucans of the lowlands manage to maintain their numbers with a single brood of young.
They rarely descend into warm lowlands and are the only toucans that attempt to rear two broods.
- Black-throated toucanet (Aulacorhynchus atrogularis)
- Blue-banded toucanet (Aulacorhynchus coerculeinctis)
- Blue-throated toucanet (Aulacorhynchus caeruleogularis)
- Chestnut-lipped toucanet (Aulacorhynchus derbianus)
- Crimson-rumped toucanet (Aulacorhynchus haematopygus)
- Emerald toucanet (Aulacorhynchus prasinus)
- Groove-billed toucanet (Aulacorhynchus sulcatus)
- Tepui toucanet (Aulacorhynchus whitelianus)
- Wagler’s toucanet (Aulacorhynchus wagleri)
- White-throated toucanet (Aulacorhynchus albivitta)
- Yellow-browed toucanet (Aulacorhynchus huallagae)