Learn how to make nest-boxes for wood-nesting native bees.
Farming for Bees: Guidelines for Providing Native Bee Habitat on Farms
Here is the email from Lisa at TPF:
For homes for native, wood-nesting bees, Casey Burns has found that 3/16" diameter holes are the most popular with the bees in our area, but a variety of sizes in encouraged. (Please see the photograph, courtesy of Casey Burns.)
For a little more info about the importance of native bees as pollinators and how to help them, here's an excerpt from the article "Nests for Native Bees" by Matthew Shepard, from Pollinator Conservation Information of The Xerces Society:
Native bees are a vital part of our environment. They ensure healthy wildflower communities and harvests of fruit and vegetables. Bees are suffering from the fragmentation and loss of their habitat and extensive use of pesticides.
Although flowers that provide nectar and pollen are important for bees, a lack of nesting sites is probably a greater threat to native bees than a lack of flowers. Unlike butterflies and other pollinator insects, bees make nests in which they create brood cells for their offspring. In many modern landscapes, a desire for neatness has usually resulted in the removal of bare ground, dead trees, and untidy corners of rough grass-all important nesting sites for bees.
The good news is that there are several easy ways in which bee nesting sites can be made. Providing suitable nest sites is a simple thing that we all can do to improve our gardens, parks, and wild areas for these important insects.
Nesting sites for solitary wood-nesting bees: The great majority of bees nest on their own, many in holes in wood. With wood nests, providing a range of hole sizes between 3/32" and 3/8" (2.5 mm to 10 mm) in diameter will support a wide range of bee species. All of these types of nest need to be placed so that the open holes face the morning sun. Not only will this warm the nests earlier in the day so the bees will become active, but it will also prevent them from overheating in the hottest part of the summer afternoons.
Nesting blocks. Bee blocks can be made by drilling nesting holes between 3/32" and 3/8" in diameter, at approximate ¾" centers, into the side of a block of preservative-free lumber. The holes need to be smooth inside, as deep as possible, and closed at one end. The length of the lumber is not critical-8" or more is good-but the lumber should be at least 4" deep. This block can be fixed firmly to a stake, fence, or building, or placed in a tree.
Twig bundles. Some plants, like teasel and bamboo, have naturally hollow stems. Cut the stems into 6" to 8" lengths. Be careful to cut the stems close to a stem node to create a tube with one end open and the other closed. Take fifteen to twenty stem pieces of a variety of internal diameters and tie them into bundles with the closed ends of the stems together. Fix each bundle to a stake, fence, or tree with the stems horizontal to the ground.
Logs and snags. Get some logs or old stumps and place them in sunny areas. Those with beetle tunnels are ideal. Plant a few upright, like dead trees, to ensure some deadwood habitat stays dry. On the southeast side of each log, drill a range of holes. Make the interior of the holes as smooth as possible. Bees don't like rough holes and may avoid them.
For more info, please visit the website of The Xerces Society, www.xerces.org
In the original Casey Burns gives his email and phone number - email us if you really want to call or email Casey a message - I don't want to post that here.
If I have any of the attributions wrong or anything else for that matter, either email us or please let me know in the comments.
Cross Posted over at Ramshackle Solid.