Keel-billed Toucans are mostly frugivorous. They eat fruits and seeds from trees such as Cercropia (green spiked fruits) and Inga and Protium. In Belize, toucans consumed fruits from fig (Ficus sp.), trumpet tree (Cercropia sp.), copal (Protium sp.), wild cherry and bread nut (Rheedia sp.). They frequented the trumpet and fig trees almost twice as often as the other tree types (Otten et al. 2001).
Other trees used as food sources include Alchornea costaricensis, Didymopanax morototoni (Skutch 1971), Astrocaryum polystachyum, Iriartea exorrhiza, Virola panamensis, Protium sessiliflorum, Cupania seemanni, Cnestidium rufescens, Salacia sp. (Van Tyne 1929), and Swartzia cubensis (Moermond and Deslow 1985). In Mexico birds were observed feeding on five species of fruit trees, but mainly on Ehretia tinifolia (Remsen et al. 1993).
Keel-billed Toucans also supplement their diets with occasional animal protein including snakes, small lizards and insects such as beetles, cicadas and ants (Skutch 1971). They prey on eggs and nestlings of small passerines (Robinson and Robinson 2001, Libsch et al. 2008).
They fly from the forest to neighboring areas with scattered trees (including forest edge, secondary forest, plantations) to forage (Skutch 1971, Graham 2001).
Food Capture and Consumption
Toucans graze palm and fig trees for edible fruits. Their large and powerful bill allows them to break open hard seeds. Fruits are seized between the tips of the mandibles, tossed back with an upward jerk of the head and swallowed whole. With some fruits, the outer husk is skillfully removed before the fruit is swallowed. Fruits with large stony pits are swallowed intact. The fleshy pulp is used and the hard pit is regurgitated. When incubating, the regurgitated pits form the lining of the nest (Van Tyne 1929). They will sometimes hold food beneath their feet (Skutch 1971).
To understand iron storage disease in Keel-billed Toucans, the mineral content of their natural foods was analyzed. Toucans in Belize consume foods that are low in iron. The iron concentrations of the four most commonly ingested food items ranged from 22 mg/g for breadnut to 150 mg/g for copal. Irons concentrations less than 50 mg/g were found in 7 of 15 food items. Toucans appear to have maximized their efficiency for iron uptake along the gastrointestinal tract to adapt to this low iron content (Otten et al. 2001).