Embedded Files
Welcome to bumble bee nesting 101! On this page, you will find foundational knowledge about nesting bumble bees. Despite bumble bees being big and boisterous insects who are known for visiting all kinds of flowers, little is known about their nests. We see bumble bees on flowers all the time... but there is much more to their life than what they eat.
What does a bumble bee nest look like?
When you think of a bee nest, your mind's eye might picture a hive hanging from a tree, made up of neat, clean, and hexagonal shaped comb. While paper wasps and honey bees make these types of nests, bumble bees nests are very different. For one thing, most of their nests are either on the surface or below the ground, not in trees. At first glance, a bumble bee nest appears as a small hole in the ground, or a clump of grass with bees going in and out in succession. Inside, wax cells can be found filled with brood as well as pollen and nectar to feed the young larva.
Bumble bees often nest in abandoned rodent dens underground or under tufts of grass. Rodents create spacious shelters and fill them with insulating materials, like grass, plant stems and fur, creating a protected place to live. This insulation in the nests allow for the queen to focus on gathering pollen and nectar to support her colony. Once the rodent moves out, bumble bees find these dens and set up their homes for the growing season - Think of it as a bumble bee moving into a vacant apartment.
A common eastern bumble bee (Bombus impatiens) leaving her nest, situated in an abandoned rodent burrow . This nest was found in an aspen grove in Washington County, Minnesota. Photo: Sami Dolan
A black-and gold bumble bee (Bombus auricomus) nesting in an abandoned bird box. It isn't unusual for bumble bees to nest opportunistically in other covered and warm areas that aren't in an underground rodent den! Photo: Zach Portman
A lab reared common eastern bumble bee (Bombus impatiens) colony. Bumble bee's are social insects and create a nest similar to honey bee's, but they appear (to the human eye, at least) much less organized and lack the classic angled shapes. The bumble bee comb looks much more like a clump of pots or bowls. Photo: Elaine Evans
Where can you see nests?
Bumble bee nests can be found in various habitats, including prairies, forests, and urban areas. When visiting natural areas, you may find nests by noticing bees entering and exiting a nest in the ground. In urban areas, you may find nests in unexpected spots, such as under the foundation of a building, in a bird house, or even the cushions of your patio furniture.
Despite the differences in nesting structures, bumble bees, like wasps and honey bees, are also social insects. This means there are many generations of related insects living together, dividing labor and sharing resources. These nests are founded by a single queen early in the season. As the season continues and nests grows in size, nests become much easier to observe. Because the nest has more workers, there is more traffic at the nest entrance, which increases the chance of us discovering the nest. Generally, the best time to find a bumble bee nest is during a colony’s peak population. In Minnesota, this period is roughly mid-July to August, but varies for different species of bumble bees.
Bumble bees do not necessarily nest in places where there are a lot of flowers. Their nesting choices are a very different aspect of their life. Bumble bees are strong fliers, and have the ability to fly over half a mile away to forage. Because of this, setting up their nest near flowers isn't the highest priority. Especially as different flowers bloom and the nest's food sources change so much throughout the season. Bumble bees nest in areas they deem to be safe and cozy homes, often which are dens created by rodents. Meaning, where rodents decided to nest, is generally also where bumble bees will nests.
How recognize a bumble bee nest?
Bumble bee nests are most easily found by observing bees entering or exiting the nest entrance. While it may be tempting to wait at every hole you find in the prairie, the best way to find a nest is to notice a bumble bee leaving the nest, or returning from a foraging flower trip and entering into the nest. This behavior of entering or leaving the nest is distinct! Check out the video of a black-and-gold bumble bee (Bombus auricomus) nest below to see this behavior. Notice the large circles the bees take as they descend into the nest - we call these orientation flights - the bees are orienting themselves to their surroundings as they are entering and exiting their nest.
A common eastern bumble bee (Bombus impatiens) descending into it's nest in a deciduous forest. Photo: Zach Portman
A northern amber bumble bee (Bombus borealis) sitting upon her surface nest in a dry prairie in Polk County, Wisconsin. Surface nesting bumble bees often use grass strung together by rodents to found their nest. Photo: Sami Dolan
A red-belted bumble bee nest (Bombus rufocinctus), shortly after being attacked by what was likely a mammalian predator. This nest was located underground, and was dug up by the predator. Photo: Geena Zebrasky
How do we learn about bumble bee nests?
Despite being so common on flowers and knowing a lot about what bumble bees eat, we know relatively little about where bumble bees are when they are not visiting a flower. Observing bumble bee nests is an important part of understanding these insects and what kind of habitat they prefer to live in. In a broad sense, we know bumble bees live in abandoned rodent dens. But there are still many questions regarding their habitat, such as:
What types of habitats do they like most? Open areas? Forests?
Do different species of bumble bees use different habitats?
What affects bumble bee nest survival?
... and many other questions...
One of the biggest barriers to observing bumble bee nests is the fact that bumble bee nests are difficult to find. The size of the entrance to a bumble bee nest varies. Many times, the entrance to a bumble bee nest is small, and may be no bigger than a penny. Other times it can be a large entrance the size of a cantaloupe. With thousands of different holes in the prairie, determining whether bumble bees are nesting in one is difficult.
Researchers use a few methods to locate nests to study them. Most straightforward, many strategies use trained human observers to locate nests directly. This has been done via high intensity surveys with a few observers, and also in collaborative efforts with the community and volunteers... Just like Nest Quest :) One study conducted in the United Kingdom, rallied 709 volunteers and found 432 nests over three years! I wonder if we can do that here in Minnesota...
Radio tracking is a method that has been used to track bumble bees throughout their habitat. This involves gluing a small radio device to a bumble bee, and releasing it back into its habitat. Observers then use the signal omitted from the radio to follow the bumble bee throughout an area to answer questions about how far it flies, what habitats it spends time in, and helping to discover nest locations. Radio tracking has primarily been used to track bumble bees across their foraging habitat. Using these techniques to learn about nests is a relatively new advancement. In 2025, Nest Quest will be using radio trackers to locate bumble bee nests.
Participatory science platforms like Bumble Bee Watch and iNaturalist are both sites that have been helpful in contributing to bumble bee nest data, allowing people to easily upload photos and report their sightings to a public database.
Lastly, trained nest-sniffing dogs have been used to locate nests via their scents. Conservation Dogs Collective is a group that is actively working with dogs to learn about bumble bee nests.
To summarize…
Unlike honey bees and social wasps, bumble bees establish their nests underground or under grass by moving into abandoned dens created by rodents. These nests can be found in various habitats. However, there is still lots to be learned about bumble bee nests, as we only have a broad understanding of their nesting preferences and requirements. In Minnesota, nests can best be found from July to August when bumble bee colonies are large and well established.
Page updated
Report abuse