error. these are the details that most commercial bee houses get wrong, especially for the native bees in our area. one size does not fit all. usually the holes are too large. we have tried them and the success rate was extremely low.
there are two basic parts to a human built bee-nesting box, the outer housing, or at least a roof, and the material that you will put into it. these inserts, wooden blocks and/or plant tubes, contain the actual holes in which the bee will construct a cell, in which they lay one egg per cell.
the actual box can be made from any scrap lumber, as long as it 