There are so many nest types built in various ways and techniques built every year for breeding but some are reused for many years. In most species, the female does most or all of the nest construction, though the male often helps. However not all species build nests. Some species lay their eggs directly on the ground or rocky ledges.
Some aquatic species such as grebes are very careful when approaching and leaving the nest so as not to reveal the location. Some species will use leaves to cover up the nest prior to leaving.
The smallest bird nests are tiny cups which can be a mere 2 cm (0.79 in) across and 2–3 cm (0.79–1.2 in) high. At the other extreme, some nest mounds measure more than 11 m (36 ft) in diameter and stand nearly 5 m (16 ft) tall.
Aquatic: Built up with sticks and debris; anchored, floating, in shallow or deep water.
Burrow: Built underground in a canal, to create a safe place for their eggs.
Cavity: Formed inside a tree using an existing cavity or create one.
Cup: Made from grasses, twigs and mud, in a tree or on the ground.
Enclosed: Similar to a cup with a small entrance hole.
Mound: Heap of twigs and vegetation in form of a mound to protect and keep the eggs warm.
Pendant: Hanging nest, woven from fine grasses.
Plate: Shallow cup made of foliage or mud.
Platform: Huge nest, for larger eggs.
Scrape: Very shallow depression lined with grasses, feathers or moss.