Like most native bees, miner bees spend much of the year under ground. They emerge in early spring, little brown bees about the size of a honeybee patrolling along the ground for the place to go back in. They like bare, sunny slopes, where the ground warms up quickly. You might see scattered holes in sunny slopes or bare patches in your lawn. Or maybe even going in and out of pencil-sized holes in between paving stones. Like all bees, they are resourceful.
The males come out first, to watch for mates. After mating, the females gather honey and pollen, and stow their provisions into little balls in the tunnels. Once there’s enough for a larva to grow up on, she lays an egg and seals up the cell. Then she starts preparing for the next one. In time, the egg will hatch, the larva will eat and mature, and then sleep underground until spring comes again.
Since these bees, and many other natives, nest in the ground, you should avoid disturbing the soil. If you find them in bare patches, leave it uncovered and unmulched; mulch will confuse them. They seem happy to find my fruit trees on sunny spring days, and I’m happy to see them every year.