Bumble bees are important pollinators that contribute to the growth of flowers, fruits, and vegetables. These fuzzy insects are generally docile and less aggressive than some other stinging insects, typically only stinging if threatened or their nest is disturbed. Understanding their nesting habits and activity offers insights into their behavior and environmental contribution.
Where Bumble Bees Nest
Bumble bee queens emerge from hibernation in spring and begin searching for a new nest site. They seek out existing cavities that offer insulation and protection from the elements, as they do not construct nests from scratch. These locations are dry, sheltered, and dark, helping to regulate the nest’s temperature and protect it from direct sunlight.
Common underground nesting sites include abandoned rodent burrows or vole nests, which provide pre-existing tunnels and insulating material. At surface level, nests can be found within dense clumps of grass, under sheds, in compost piles, or beneath log piles. Less frequently, bumble bees may establish nests above ground in places such as birdhouses, wall cavities, attics, or even tree holes. The queen lines the chosen cavity with materials like dry grass, leaves, or animal fur to insulate it for her eggs and developing colony.
Identifying Nesting Activity
Identifying an active bumble bee nest relies on observing specific behaviors rather than directly seeing the nest itself, as many nests are hidden. A consistent flight path, where bees fly in a direct line to and from a particular spot, is one indicator. This sustained pattern of movement, as opposed to a single foraging bee, suggests a regular entry and exit point for a colony.
Another sign of nesting activity is the presence of bees returning to a specific area with visible pollen sacs, known as corbiculae, on their hind legs. Female worker bees collect pollen to feed the developing larvae within the nest, so observing them carrying pollen indicates an active colony. An increased concentration of bumble bees in a localized area, especially during peak foraging hours, can also point to a nearby nest. Look for small holes or crevices where bees are frequently entering and exiting, as these serve as the nest’s entrance points.
Safe Observation of Nests
When a bumble bee nest is suspected or located, maintaining a respectful distance is important to avoid disturbing the bees. Observing from at least 3 feet away is recommended. Bumble bees are generally not aggressive, but they can sting if their nest is threatened or provoked. Avoid touching, poking, or blocking the nest entrance.
Approaching a nest with calm and slow movements can help prevent alarming the bees. Rapid or sudden movements might be perceived as a threat, leading to defensive behaviors. If a nest is found in an area with high human or animal traffic, and its presence causes concern, contacting a local bee expert or a pest control service specializing in bee relocation is recommended. Attempting to remove a nest oneself can be risky and is not recommended. Allowing bumble bees to remain undisturbed is beneficial, as their nests are annual and will naturally conclude their cycle after a few months.