There is a diversity of types of nest constructed. Not all birds construct nests of twigs, leaves and grass placed on a tree limb. A range of techniques are used to create a wide variety of structures. Woodpeckers are cavity nesting birds and excavate nesting site in a tree. Bald eagles reuses their nest from previous years, adding new material to the platform each year.
Some birds reuse the nests of other species.
A clutch is a batch of eggs laid in a single breeding attempt. Some birds may only lay one egg per clutch such as vultures. While other birds such as pheasants lay up to a dozen eggs per clutch. In cases where the clutch fails, some birds will relay eggs during the same season. Some species of birds will lay several clutches per season.