By far the most common type of bird boxes are made of wood because of their durability and natural look. Cedar and cypress are popular choices that will not split under pressure. Pressure treated pine can also be a good choice. Wooden nest boxes can be nailed to a post, attached to a tree trunk or even adhered to a window with suction cups. The latter type of box typically has a clear back so people can watch nesting activity, without disturbing the birds, from the comfort of their window seat. To keep a wooden box clear of lingering parasites, remove abandoned nests and debris.