Mining bees are solitary bees with a life cycle similar to other solitary bees. The males are much smaller than the females, and also live only to mate. The mining bees emerge in the Spring, mate, and then the females work hard to lay eggs for 4-8 weeks. They are not aggressive, as is the case with solitary bees, so no reason to fear them!
The unique quality of these bees, is the branching burrows underground. They form a small tunnel system, in which, they build egg cells. The female begins by scouting out the perfect muddy (they love clay-like mud) spot, protected by some kind of covering, such as shrubs, and begins digging. She digs into the ground forming a branching system, similar to that of the carpenter bee burrows in wood. She then lines the cavity with a clear liquid that seals the egg cells, making them waterproof. Finally, she builds a an entrance, which looks much like a mini volcano.
After she has completed the nest preparation, she begins foraging for pollen and nectar. You know what this means, mining bees are great pollinators! She collects nectar and pollen provisions for each egg, and lays the egg on atop the provision, and seals the cell with mud. She continues this work cycle until all eggs are laid. The final step to ensure the nest is safe, is to seal the entrance with another mud plug. The eggs will pupate into adults by Fall and will stay in a resting state until the following Spring! The cycle will then repeat itself, and if you are lucky, you will notice these little bees in your own yard!
To be a great host to these bees, provide open mud, absent of mulch or plants. Bare ground under a bush or tree is desirable as they provide some protection from the elements. Additionally, of course, plant native flowering plants in your yard.