48 hole Alder Reusable Seasoned Habitat Boards. This is the absolute best and one of the only ways that gardeners should help house native bees. Specifically blue orchard Mason bees. You should not buy blocks of wood with holes drilled in them because you cannot access the bees inside to check for disease or other pests that may take over your habitat. Native bees only like specific types of wood such as this Alder hardwood. These boards are much more desirable than others you can find on line because I have kept them a year and had native bees in them which is stronger than any lower or attractant available. This smell like home and like baby bees. You will have a much higher success rate using not only these boards combined with a package of bees. It is just fine to buy these boards alone without one of the boxes that we sell and without the package of bees. You can put this habitat boards in your own Box built to suit, a large metal can or somewhere a bit out of the weather. We do sell boxes that fit these exactly. I really like to combine these with sustainable reeds we sell. In the past we have had rubber bands keeping them tightly together with cardboard on the back to try and keep bad bugs such as beetles and predatory wasps out. We have now found that simple drywall putty or the painting spackle pushed into the holes slightly in the back will do wonders to protect your bees. Not only is it highly economical but it pulls apart easily when you go to inspect your bees. Why do you want to protect your bees from the back? Many different bugs will attempt to access the bees from the back. This is why we have a sealed (yet removable) back of your habitat house that we sell as well as trying to close off the back of the laminate board holes. When the bees lay their eggs they lay the females towards the back which are the most important and most prized, If you have a bad predatory bug infestation though go for most of the females and will dramatically decrease your colony.