One secretive nester, the marbled murrelet, locates its nest high in the canopy of ancient Douglas firs over 300 years old. It uses its own saliva to glue its nest, a little pad of feathers, to the vertical underside of a palm frond. The two eggs are also glued to the nest and the parents incubate them by turns, clinging to the nest. The swiftlets build their nests high up on the roofs of a cave. 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.