Native bee nesting block study model

Nesting blocks are simple wood structures that provide habitat for native bees.  Bees typically nest inside of woody stems or underground.  Nesting blocks can be made from a variety of materials (bamboo, paper straws, fallen logs), but I decided to work with standard pine lumber.  Nesting blocks should always be constructed from untreated lumber.  There are a variety of drill bit sizes that can be used to drill the holes (3/32" - 3/8"), and the holes should be 3 - 5 inches deep.  Holes should be around 3/4" apart from one another.  The cavities can be drilled directly into solid lumber, but maintenance of these blocks is more tedious.  Drilling the holes in between planks of wood can be more time consuming during construction, but expandable nest block are easier to maintain, and help prevent the spread of disease among bees.