The Yellow-throated Toucan is the bird most people think of when we say toucan. It is one of the species that appears on books and tourism guides, the other one being the Keel-billed Toucan, which is smaller. I had heard the calls of these birds, but I did not know it was this toucan until I got close enough to see the birds. All Toucans have a feature in common: While they like to eat fruit and small amphibians, they also predate nests, either for eggs or hatchlings. Most other bird species in Costa Rica are fearful of any kind of toucan, and some of them react violently to their presence, in an effort to steer them away from their nests. Only big predator birds (like the Crested Hawk-Eagle) are known to predate on them.
I have observed an interesting behavior many times: Tanagers, Orioles and Honeycreepers were feeding peacefully on the feeder, but whenever a Toucan closed in, all the other birds flew away and stayed in a nearby tree, calling and calling loudly. As soon as the Toucan left, all birds returned to the feeder in frenetic mode, like food was going to end soon.