Brooding – National Zoo, Washington, DC

During incubation, the female Von der Decken's Hornbill lays two or three white eggs in a tree hole, which is blocked off with a cement made of mud, droppings and fruit pulp. There is only one narrow aperture, just big enough for the male to transfer food to the mother and the chicks. When the chicks and the female are too big to fit in the nest, the mother breaks out and rebuilds the wall, then both parents feed the chicks.