Each species of parrot has its own type of nestbox requirements. The following advice is therefore general, and you should always seek advice on your particular type of parrot.
A deep box is generally advisable – something sufficiently gloomy to make parent and chicks feel safe and secure. An inverted L-shaped box is a popular choice, giving the parrot easy access to a nesting ‘shaft’ not immediately visible from the box entrance.
Yellow variety Ring-Necked Parakeet
In an L-shaped box, the nesting area will need some form of ladder to give the bird easy access from the entrance to the bottom of the box. Wooden slats or dowelling nailed safely to the side is a good option.
Gnawing wood actually stimulates the breeding instinct in Parrots, so a supply in the cage is a good ploy. The pulp can then be used by the birds as part of the nest.
Nest boxes will need an inspection door in the side, somewhere at the level of the top of the nest. A peephole in the top of the box is a bad idea, as it will frighten the nesting bird. If the birds are over-nervous or aggressive, resist the urge to spy on them constantly.
The nestbox entrance should be narrow – parrots like to squeeze into their boxes, and anything too wide will not be as inviting or them.