Materials and General Instructions
For boxes erected outside the best materials are 1″ thick rough cut western cedar, cypress or redwood. All these will withstand weathering. Boxes which are placed inside buildings can be made of less expensive pine or plywood. If a wood preservative or paint is used, apply it only to the exterior of the box. When constructing closed boxes, the size of entrance holes and their height above the floor of the box are important and the dimensions given should be used. Proper hole size and placement will allow the birds to come and go freely and still keep a raccoon from entering or reaching the young.
Closed boxes should have the roof, or one side, hinged, providing access to the inside for cleaning and maintenance. Roofs can be shingled for added protection from the weather. Be sure nails and screws used in construction do not protrude inside the box. Generally, boxes should be mounted so the holes face southeast. In new or freshly cleaned boxes, a layer of pine shavings should be applied to the floor which will help contain the eggs and make incubation easier. Use only a one inch thick layer, no more, as eggs can get lost in shavings that are too deep. Do not use cedar shavings or sawdust. If ingested along with food, cedar oil can be dangerous and sawdust harmful to nostrils and eyes of the young birds.
For any nest box to be successful there are a few requirements which must be met regarding where and how the box is placed. First, proper habitat of each raptor must be chosen and within that habitat the proper type of nest box supplied for that bird. For instance, even a well constructed Barn Owl box will not be productive if placed in a wooded area. Barn Owls do not hunt or nest in woods, but are birds of open country. So it is important to know something about the lifestyle of each raptor we are dealing with.
Let’s then look at each individual species, see where it lives, what type of nest box it requires and how and where to place the boxes.