Now is the time to spot queen bumble bees. This month, fertilized queens or gynes who have survived the winter are out seeking nesting cavities. Abandoned rodent holes, hollow trees, and bunch grasses are all potential nesting sites.
Bumble bees use existing cavities—they do not destroy wood. After she establishes her nest, the queen will spend about a month gathering pollen and nectar, which she will place in waxen pots for her offspring to eat. Her first generation of children will all be female workers.
Once they metamorphosize from eggs to larvae to adult bees, they will take over foraging duties so the queen can focus on egg laying and no longer have to leave the nest. For more on bumble bees, google xerces society bumble bee information.