The toucan is a medium sized bird with a large beautifully colored beak, and it is native to the rainforests of Central and South America and the Caribbean. The toucan is mostly known as a frugivorous bird (one that feeds on fruits), and their primary ecological function is seed dispersal because of their long distance movement in the forest.
Toucans less frequently prey upon invertebrates and small vertebrates. Previously there was some evidence of toucans feeding on the eggs of cavity-nesting birds, but they have rarely been seen feeding on eggs from ground-nesting birds. It was presumed that toucans don’t feed on eggs from ground-nests. Cove et al. (2016) conducted research at La Selva Biological Station in Costa Rica where they established artificial tinamou (Tinamidae) nests throughout the station with three eggs in each nest. The eggs were dyed with light-blue color to match the characteristic color of tinamou eggs. The nests were located at points which were suitable for ground nesting, such as “open canopy” in the forest due to fallen trees or fragmented areas.  To monitor the predator activity, camera traps were set at each location with heat and motion sensors to photograph predation events throughout the week. Camera traps were set 2-3 meter away from ground-nests and left activated for one week for each nest.
On two different occasion toucans were seen trying to consume ground-nest eggs. This study was the first time that a toucan was seen consuming ground-nest eggs. The aracari toucan was unsuccessful, and it left after the 40th attempt trying to break the egg shell. But the keel-billed toucan came to the forest floor, disturbed the nest and then consumed all three eggs. The unusual behavior of the toucan might be explained a few different ways: either the resource unavailability made the toucans prey on ground-nest eggs, foraging on the forest floor by toucans is common, or maybe toucans are more opportunistic that other birds, particularly in the disturbed and fragmented forest where fruit trees can be limited.
This study reveals that toucans have a novel node in the terrestrial food web and they are a potential competitor of terrestrial nest predators, which mostly include mammals. This could result in substantial interaction. For instance, diurnal toucans have better color vision compared to mammals, and they can find ground-nest eggs easily compared to nocturnal mesopredators. Therefore toucans can play a functional role in reducing the abundance of birds nesting on the ground and can exert selection pressure through nest depredation.

Citation:

Cove, M. V., Fernandez, C. M., Alvarez, M. V., Bird, S., Jones, D. W., & Fagan, M. E. (2017). Toucans descend to the forest floor to consume the eggs of ground-nesting birds. Food Webs,10, 2-4. doi:10.1016/j.fooweb.2017.01.003