Bombus sandersoni
In 3 days ~30% in a week ~60%
Bombus sandersoni is a species of bumblebee known commonly as the Sanderson bumblebee. It is native to North America, where it occurs across Canada and in the eastern United States. The queen is 15 to 16 millimeters long and 6 millimeters wide at the abdomen. It is black with pale hairs on the head and yellow on the abdomen. The worker is up to 13 millimeters long and 5 millimeters wide. It is similar to the queen except the tip of the abdomen is black. The male is 10 to 13 millimeters long and 5 to 6 millimeters wide. It has long hairs, yellow on the head and part of the abdomen and black at the end of the abdomen.
This bee occurs in maritime Canada, temperate forest, the Canadian Prairies, tundra, and taiga. It lives in and around wooded areas. It feeds on several types of plants, including cohosh, fireweeds, kalmia, honeysuckles, bergamot, blackberries, and bilberries. It nests underground.
This bee has faced no significant declines. It may, however, be more sensitive to climate change than other bee taxa. This species was found to harbor the bee parasite Nosema bombi. Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Isle Royale National Park | 🇺🇸 United States | |
| 2 | Riding Mountain National Park | 🇨🇦 Canada | |
| 3 | Great Smoky Mountains National Park | 🇺🇸 United States |
With luck
About 10% of wildlife watchers report a Sanderson's Bumble Bee sighting in Riding Mountain National Park on a given day, based on 17 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 37th most-seen of the 104 insects we can rate there. Over three days the chance rises to about 30%, and over a week to about 60%, if each day is a fresh chance.
June and July
In those months about 20% of wildlife watchers report a Sanderson's Bumble Bee in Riding Mountain National Park on a given day, against under 5% in August to April, the lowest months. Those are among Riding Mountain National Park's wettest months, with about 85 mm of rain a month against 20 mm in February.
Between noon and 3 pm
Across all the parks we cover, that three-hour window holds the most Sanderson's Bumble Bee sightings with a recorded time, and about 9 in 10 of them come between 6 am and 6 pm: it is a daytime animal.
Among the best
Of the 3 parks where we can rate Sanderson's Bumble Bee sightings, Riding Mountain National Park ranks 2nd at about 10%, level with the leaders once rounded. The best odds are in Isle Royale National Park (United States, about 10%).
Same genus: Bombus
The closest relatives of the Sanderson's Bumble Bee that you can see in Riding Mountain National Park (genus Bombus, Bumble Bees) are Tricolored Bumble Bee (about 30%), Perplexing Bumble Bee (about 20%) and Nevada Bumble Bee (about 20%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Sanderson's Bumble Bee is recorded against all the insects logged in Riding Mountain National Park (17 verified sightings from 2019 to 2026), calibrated against known sighting rates. Figures are rounded to the nearest 10% because citizen-science data supports honest approximations, not decimals, and months with records from fewer than five people show "—". How it works.
