Open Top Style
Open top boxes can be made with ¾" to 1" plywood or, if a particular pair tends to chew the plywood too much, similar sized hardwood planks can be used. There should be at least two feet of clearance above the box to allow the birds to comfortably perch on the edges. This allows the birds to drop the splinters, which make up their nesting material, into the box.
This slanted entrance nest box is constructed from "Trespa", an extremely hard material formed from layers of paper pressed together under extremely high pressure. The nest boxes have very wide openings over which replaceable entrances of much softer wood of the appropriate thickness is mounted. The wood used for the palm cockatoos is at least 2 cm thick. (King, C., pers. comm.)
