Housing Solitary Bees
There are hundreds of species of solitary bees in the western U.S. They are called solitary bees because they, unlike social bees (honey bees and bumble bees), do not live in colonies. Each solitary bee female works alone, collecting nesting materials for constructing her nest, and collecting pollen and nectar for her brood. Some species cut circular pieces out of leaves or flower petals to construct neat little cups, while others collect resin or mud. Solitary bees are first-rate pollinators, making them a great bonus in urban gardens, natural areas, and agricultural settings.
Nests are often built in nail holes, or under loose bark or shingling. Female solitary bees will readily nest in holes provided for them by drilling in blocks of milled lumber or in log sections. Drill holes three to six inches deep and about 1 inch apart, using a ¼” to 3/8” drill bit.
For more information on providing nests for native bees, visit: http://www.xerces.org/wp-content/uploads/2008/11/nests_for_native_bees_fact_sheet_xerces_society.pdf