Toucans aren’t just found on the Fruit Loops cereal box, they are near passerine birds from the neotropics, most closely related to American barbets. They are brightly marked and have large, colorful bills. The family includes five genera and about forty different species. The name of this bird group is derived from Tupi tucana, via French.
The colorful, giant bico (bill), which in some large species measure more than half the length of the body, is the hallmark of toucans. Despite its size it is very light, being composed of bone struts with little solid material between them. The bill has forward-facing serrations resembling teeth, which historically led naturalists to believe that toucans captured fish and were primarily carnivorous, but today we know that they eat mostly fruit. Why the bill is so large and brightly colored is still debated and may be complex. As there is no sexual dimorphism in coloration it is unlikely to be a sexual signal; It does aid in their feeding behavior (as they sit in one spot and reach for all fruit in range, thereby reducing energy expenditure). It has also been theorised that the bill may intimidate smaller birds, so that the toucan may plunder nests undisturbed. Also, the beak allows the bird to reach deep into treeholes to access food unavailable to other birds, and also to depredate suspended nests built by smaller birds.
Toucans are primarily frugivorous (fruit-eating), but are opportunistically omnivorous and will take prey such as insects and small lizards. Captive toucans have been reported to actively hunt insects in their cages, and it is possible to keep toucans on an insect-only diet. They also plunder nests of smaller birds, taking eggs and nestlings. This probably provides a crucial addition of protein to their diet. However, in their range, toucans are the dominant frugivores, and as such play an extremely important ecological role as vectors for seed dispersal of fruiting trees.
Toucans are arboreal and nest in tree holes (either natural cavities or holes excavated by for instance woodpeckers – the toucan bill has very limited use as an excavation tool) laying 2–4 white eggs. The young hatch completely naked, without any down. Toucans are resident breeders and do not migrate. Toucans are usually found in pairs or small flocks, within which bill fencing and wrestling may occur, probably to establish dominance hierarchies.