Overview
The bumble bee is the big, fuzzy, unhurried bee bumping between garden flowers all summer — and it’s one of the most beneficial and least threatening insects an Ontario homeowner will ever meet. Bumble bees (Bombus species) are native pollinators, several of which are in decline, and they’re famously gentle. Trouble, when it happens, is almost always about location: a colony sets up in an abandoned rodent burrow beside a patio, under a shed step, or in wall or attic insulation, and a family suddenly has bees coming and going near a doorway. The important thing to know up front is that a bumble bee colony lasts a single season and dies out completely by fall — so in most cases the right answer is patience, not pesticide.
Identification
Bumble bees are large — 15 to 25 mm — round, and densely furry, with bold black-and-yellow bands (some Ontario species add orange or a white tail). That thick fuzz covering the whole body, including the abdomen, is the quickest way to separate them from the similarly large but glossy-bottomed carpenter bee. They fly with a distinctive low drone and are unbothered by people nearby.
| Feature | Bumble Bee | Carpenter Bee |
|---|---|---|
| Abdomen | Fuzzy, yellow-banded | Shiny, black, hairless |
| Overall look | Round and furry all over | Robust, bald on top of abdomen |
| Nesting | Ground burrows, cavities, insulation | Round holes bored in wood |
| Damages wood? | No | Yes |
| Behaviour | Forages on flowers | Hovers and drills around wood |
The other common confusion is with ground-nesting wasps like yellowjackets, which also use old rodent burrows but are smooth, narrow-waisted, and far more aggressive. If the insects going into a lawn hole are slim and bright with a pinched waist, treat it as a wasp problem, not a bee one.
Life Cycle
Bumble bee colonies are strictly annual. In spring, a single overwintered queen emerges, finds a suitable cavity, and raises her first small brood of workers alone. Through summer the colony grows — typically to a few dozen and up to a few hundred workers, far smaller than a honey bee hive. Late in the season the colony produces new queens and males, which leave to mate. Then, at the first hard frosts, the founding queen, all the workers, and the males die. Only the newly mated queens survive, burrowing a few centimetres into loose soil to hibernate through the Ontario winter before starting the cycle again. No nest is ever reused.
Habitat & Behaviour
Bumble bees look for pre-existing cavities rather than excavating their own. Favourite Ontario sites are abandoned mouse and chipmunk burrows, the space under sheds, decks, and porch steps, compost heaps, thick grass tussocks, and — where they find a gap into the building envelope — wall voids and attic insulation. Colonies stay small and low-key; you’ll notice a nest mainly by steady bee traffic in and out of a single hole or gap — the same envelope gaps that let in mice and other pests around homes in Innisfil and Barrie. Foraging bumble bees range widely and are entirely peaceable away from the nest, working flowers even in cool, damp weather when other bees stay home.
Diet
Like all bees, bumble bees feed on nectar and pollen. They’re generalist foragers and superb pollinators, and their large bodies and “buzz pollination” technique make them especially effective on tomatoes, blueberries, and many native plants. They don’t scavenge human food or garbage — again, an insect doing that is a wasp, not a bumble bee.
Signs of Infestation
- Steady bee traffic into a single ground hole, gap under a structure, or wall opening — the main sign of a nest.
- A low buzzing heard from insulation, a wall, or under decking on warm days.
- Large, fuzzy bees repeatedly disappearing into the same spot in the lawn, under a shed, or into a soffit gap.
- Peak visibility in July and August, when the colony is largest and worker traffic is heaviest.
Damage Caused
Effectively none. Bumble bees don’t chew wood, don’t excavate structural material, and don’t store the large honey caches that make honey bee wall colonies a problem. A nest in insulation may compress a small area of it, but bumble bees cause no meaningful structural or property damage. Their only real “cost” is the inconvenience and sting risk of a colony sitting in a high-traffic spot — and that resolves itself when the colony dies in fall.
Health Risks
Bumble bees are low-risk. Female bumble bees can sting repeatedly (they don’t lose the stinger the way honey bees do), but they’re reluctant to, doing so only when the nest is grabbed, stepped on, or hit with a mower. For most people a bumble bee in the garden is no concern at all. The meaningful exception is someone with a diagnosed bee-venom allergy: a nest beside a door, in a deck they use daily, or near a child’s play area justifies removal on safety grounds even though the bees are otherwise harmless.
Seasonal Activity in Ontario
Queens emerge in April and May and search for nest sites — this is when you may see an unusually large lone bumble bee investigating holes near your foundation. Colonies build through June, reach peak size and visibility in July and August, and produce next year’s queens in late summer. Cool-tolerant bumble bees keep foraging into September and October, later than most bees. The colony dies at the first hard frosts, and by late fall only hibernating queens remain, tucked into the soil until spring.
Where They Hide
Underground in abandoned rodent burrows is the classic bumble bee nest, but Ontario homes offer plenty of alternatives: under sheds, decks, and porch steps; inside compost bins; in dense ornamental grasses; within wall and attic insulation reached through a gap in the envelope; and occasionally in odd cavities like bird boxes or outdoor furniture cushions left undisturbed.
How They Enter Homes
Bumble bees don’t force entry — they exploit openings that already exist. A queen slips through a gap in siding, a torn soffit, an unscreened vent, or a foundation crack and finds the insulation behind it a ready-made nest cavity. Sealing these same gaps that let in mice and other pests also keeps a spring queen from choosing your wall in the first place.
Prevention Tips
- In spring, before queens are hunting nest sites, seal gaps in siding, soffits, and around foundation and utility penetrations.
- Screen attic, gable, and dryer vents with fine mesh.
- Keep compost bins closed and turned, and remove old rodent burrows near patios and doorways.
- Cut back dense grass tussocks close to high-traffic areas.
- Store outdoor cushions and rarely-used equipment where a queen can’t nest undisturbed.
- If a nest appears in a low-traffic corner of the yard, mark it, give it space, and let the season end it.
DIY vs. Professional Treatment
For most bumble bee nests, the honest recommendation is to do nothing — they’re beneficial, declining pollinators, and the colony is gone by winter. DIY sprays kill a valuable insect unnecessarily, and Ontario’s cosmetic pesticide rules limit what homeowners can legally apply anyway. When a nest truly can’t be tolerated — it’s in a doorway threshold, under a deck used daily, or near someone with a sting allergy — professional residential pest control is safer than a ladder-and-spray attempt, especially inside walls or insulation where the nest is hidden. Sani IQ will identify the species, tell you plainly whether treatment is even warranted, and handle the genuinely problematic nests, backed by our Pest-Free-Or-It’s-Free guarantee. Not sure what you’re dealing with? Start with our free quote quiz.
References
- University of Minnesota — Bumble Bee Nesting 101
- Xerces Society — Bumble Bees: Nesting and Overwintering
- Government of Ontario — Using Pesticides in Ontario
Last updated: July 16, 2026 · Reviewed by Sani IQ licensed technicians