While a nest, by definition, is a place for the nurturing of offspring, some birds have much more expressive impulses. The male bowerbirds of New Guinea and Australia build amazing "statement architecture" to woo multiple mates (up to two dozen), who then go off and lay eggs in a simple cup nest.
The bowerbirds' ostentatious creations are made of sculpted grasses and sticks, lavishly decorated with colorful objects such as bones, stone, shells, and bottle caps. Even a spoon, a toothbrush, and a glass eye have been found in some displays. Bits of glass and piles of berries are carefully arranged and color-coordinated and anything out of place is removed in an obsessive frenzy. Depending on the species, the arrays can take the form of an avenue or maypole or even a stage to perform his enthusiastic, and hopefully alluring, dance movements for the females.
Here is a nest built by a satin bowerbird (Amblyornis inornata) and decorated with blue flowers, berries, and bits of plastic.