He dribbles long sticky strands, using his beak as a shuttle to weave a cup-shaped bracket onto the cave wall. Birds employ the most astonishing strategies to conceal their young from predators. The female hornbill seals herself into the nest and stays inside the tree cavity throughout incubation, leaving only a tiny aperture. But she was careful to spend a few days testing the male's ability to provide her with food before she committed herself to laying. Birds will use any available material that they can carry away to build their nest - leaves, sticks, mosses, lichens, feathers.
Ovenbirds are some of the finest nest building craftsmen.
They make a variety of nests, ranging from clay domes to stick nests, with intricate tunnel entrances and even underground burrows. In many species females will carefully peruse the design and quality of the nest the male has build. The hammerkopf builds what must be the most extraordinary construction in the bird world. The huge, domed nest up to six feet high and across, is made of sticks, reeds and grass and can weigh up to 50 kg. The nest is placed in a tree fork, on a cliff or on the ground.