A quick search of the internet will reveal plenty of anthropomorphic throw-away lines like "it's impossible to take toucans seriously". That could only be written by someone who's never watched wild toucans, stunningly beautiful and clearly intimidating to many of their neighbours. I suspect the authors of such lines are much more familiar with the clownish caricatures of toucans from cartoons and advertising logos.
Yellow-throated (also called Black-mandibled) Toucan Ramphastos ambiguus, Wild Sumaco Lodge, Ecuador. At 60cm long and up to 750 grams, this is one of the largest toucans, and is found from southern Peru to Central America. This one was about to tuck into the cluster of long Cecropia fruits behind it - toucans are great fruit eaters. The colourful plumage, bill and bare facial skin are typical of toucans. |
There are some 45 species recognised, all in the Family Ramphastidae, found throughout tropical South and Central America, except for the Pacific desert coast. All are solely or mostly rainforest birds, except for the largest and probably most-recognised of them all.
All toucans rely on hollows for nesting. While some of the big ones can do some enlarging of soft rotted wood, for the most part those bills aren't useful for such heavy work, though some of the green toucanets, small toucans in the genus Aulacorhynchus, can manage it. Accordingly most need to find a large tree cavity which is either natural or been excavated by someone else.
Plate-billed Mountain Toucan Andigena laminirostris, north-western Ecuadorian Andes, at nesting hollow. (And this one wouldn't let me get a better angle!) |
However, so much of toucan lore is about the bill, unsurprisingly. Obviously one major function is food-gathering. As mentioned, toucans are fundamentally fruit-eaters, targetting a wide range of fruiting trees; as such they are very important vectors of seeds of rainforest trees and climbers.
This fondness for fruit also makes toucans regular visitors to feeders throughout much of their range, enabling closer views of wild toucans than we would ever be likely to get otherwise.
However most toucans are also fond of some meat in their diet. Many rob nests, both by probing into tree hollows and ripping apart hanging nests such as those of caciques; birds regularly mob them to try to move them on. They will also hunt almost anything they can catch on occasions, from insects to small birds, lizards, frogs, snakes and small mammals.
As can be seen in some of the photos, including the previous one, many toucans have forward-pointing 'teeth' in the upper mandible. While it is often asserted that the purpose is to rip fruit apart, there appears to be no evidence to support this. Others suggest that they might be to assist in intimidatory postures, such as defending a fruiting tree, or warding off mobbing birds trying to prevent nest robbing, but while these activities certainly occur, there again seems to be no evidence of the bill 'teeth' playing a role in this. The aracaris seem to have the most-developed bill teeth; here are a couple more examples.
Chestnut-eared Aracari, Pousada Arara, northern Pantanal; these are common visitors to feeders. |
The bright colours of the bill - evident in some of the photos in this posting - also suggest a role in courtship displays.
However, recent work has shown that another purpose of the bill, and possibly the major one, is to disperse heat, a key problem for any tropical bird, especially a larger one, given that birds don't sweat and have limited bare skin. Toucans have complex blood networks in the bill, which can be opened or closed to control blood flow near the surface, restricting it to conserve heat, increasing it to shed heat. Infrared thermal imaging showed rapid heat transfer from the body to the bill - such as when the bird was about to sleep - and equally rapid 'dumping' of this heat from the bill to the atmosphere. (More recently, acting on this tip-off, other workers have confirmed that hornbills, an unrelated Old World group of big-bills, do exactly the same thing.)
I'm going to end this introduction to the wonderful toucans by featuring more examples of the three groups (representing genera) that we've already met, plus the two that we haven't yet encountered here. I've included a couple of fairly ordinary photos in order to share as many toucan species as possible.
The big 'typical' toucans, such as the Yellow-billed and Toco above, are all in the genus Ramphastos (from which the family is also named). Here are three (or maybe four?) more of them, of the eight generally recognised.
Choco (not to be confused with Toco!) Toucan Ramphastos brevis, Rio Silanch, north-west of Quito, Ecuador. The Choco is a hugely biodiverse region of western Colombia and Ecuador. |
Green-billed (or Red-breasted) Toucan Ramphastos dicolorus, Trilha dos Tucanos Lodge, near Sao Paulo, Brazil. This lovely toucan is limited to south-eastern Brazil and adjacent Argentina and Paraguay. |
Channel-billed Toucan Ramphastos vitellinus, Chapada dos Guimarães NP, south-western Brazil. This blue-faced beauty (which was being very coy) is limited to north-eastern South America. |
The aracaris (genus Pteroglossus) form the largest toucan group, with 14 species; as well as the three above, here are four more.
The mountain toucans are a small genus of four species from the Andean cloud forests. We met Plate-billed earlier from Ecuador; here's another.
Grey-breasted Mountain Toucan Andigena hypoglauca, El Cajas NP, southern Ecuador. Its range is a narrow strip of the Andes from Colombia to Peru. |
There are 11 of the little green toucanets, genus Aulacorhynchus.
Finally there are six of the 'dichromatic toucanets', genus Selenidera. The name refers to the fact that almost alone of the toucans, they have differently coloured sexes (in most of the rest the females have smaller bills, but are otherwise pretty much indistinguishable from their mates).
This handsome pair were among the amazing throngs in front of the Wild Sumaco balcony in the eastern Andean slopes of Ecuador.
Golden-collared (or Red-billed) Toucanets Selenidera reinwardtii, female above and male below; without prior knowledge, they could easily be mistaken for separate species. |
Well that's it for today. I hope this small offering has helped to lift the toucans off the cereal box, stout bottle label and cartoon strip, and back to their special place in the world. They really are much more than just a caricature!
NEXT POSTING THURSDAY 7 NOVEMBER
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