Toco toucan (ramphastos toco) predation on buff?necked ibis (the-risticus caudatus) eggs and nestlings

Abstract

Toucans (Ramphastidae) are primarily frugivorous birds that occasionally prey on eggs and nestlings of other birds, often Passeriformes. Here, we report predation events by the Toco Toucan (Ramphastos toco) on eggs and nestlings of the Buff-necked Ibis (Theristicus caudatus) at the “Buraco das Araras” ecological reserve, Mato Grosso do Sul, central Brazil. At least three of six ibis nests monitored between October 2016 and January 2017 were depredated by the Toco Toucan. In one nest, the single egg was carried to a nearby perch, where the embryo was swallowed completely. In two other nests, the nestlings were 10-15 days old when are depredated. The toucan killed the nestlings by grabbing the head with the beak and shaking vigorously, probably attempting to break the neck. During the attack, the nestlings tried to defend themselves by snapping their bills at the toucan. Once a nestling stopped reacting (dead or dying), the toucan fed on pieces of flesh from the neck. To our knowledge, these are the largest eggs and the heaviest birds preyed upon by toucans.