Bumble bees, with their distinctive fuzzy bodies and gentle hum, are familiar sights in gardens and natural spaces. Many people associate bee nests with hanging structures in trees or eaves, but the nesting habits of bumble bees are often different from those of honey bees. A significant number of bumble bee species establish their colonies underground, a behavior that provides them with specific advantages for raising their young.
Bumble Bees in the Ground
Bumble bees do not excavate their own burrows but instead utilize existing cavities for their nests. These opportunistic nesters frequently inhabit abandoned underground tunnels created by small mammals like mice or voles. The queen adapts these pre-formed spaces for her colony. Ground nests can also be found in dense tussocks of grass, beneath compost piles, under sheds, or within rock piles.
A typical ground nest features a small entrance, sometimes as narrow as a penny, leading to an underground chamber. Inside, the queen constructs wax cells to house her brood and store pollen and nectar for developing larvae. Former rodent burrows often contain insulating materials like grass, plant stems, and fur, which the bees use to line their nests. This natural insulation helps regulate the nest’s temperature, protecting the colony from extreme weather and reducing the energy bees need for thermoregulation. Underground locations also offer enhanced protection from predators.
Above-Ground Nests
While many bumble bee species prefer underground nesting, others establish colonies in various above-ground locations. These alternative nesting sites are dry, concealed cavities that offer shelter. Examples include dense vegetation, undisturbed leaf or lumber piles, and structures like bird boxes.
Bumble bees may also nest in tree hollows, wall cavities, or sheltered spots under patio furniture. These locations provide protection from elements and predators, similar to underground sites. This adaptability in nesting preferences allows bumble bees to thrive in various habitats, from natural landscapes to urban environments.
Living Alongside Bumble Bees
Bumble bees are docile and not aggressive insects. They only sting if they feel directly threatened or their nest is disturbed. Only female bumble bees possess stingers, and unlike honey bees, their stingers are smooth, allowing them to sting multiple times without dying. If you observe bees frequently entering and exiting a specific hole or opening, particularly from mid-July to August when colonies are at their peak, it may indicate an active bumble bee nest.
If a bumble bee nest is discovered on your property, leave it undisturbed whenever possible. Bumble bee colonies are annual, naturally dying off by late fall, and the nest will not be re-used the following year. These bees are beneficial pollinators that contribute to the health of our ecosystems and the production of many fruits and vegetables. If a nest is in a hazardous location, such as a bird box, it can sometimes be carefully relocated at night when the bees are less active. Using a red light can be helpful during relocation, as bumble bees do not perceive red light well.