Bombus affinis
In 3 days ~10% in a week ~20%
Bombus affinis, commonly known as the rusty patched bumble bee, is a species of bumblebee endemic to North America. Its historical range in North America has been throughout the east and upper Midwest of the United States, north to Ontario, Canada, where it is considered a "species at risk", east to Quebec, south to Georgia, and west to the Dakotas. Its numbers have declined in 87% of its historical habitat range. In April 2010 it was assessed as Endangered in Canada, through the work of Sheila Colla and colleagues. On January 10, 2017, the United States Fish and Wildlife Service placed B. affinis on the list of endangered species, making the rusty patched bumble bee the first bee to be added to the list in the continental United States (seven species of yellow-faced bees native to the Hawaiian islands were added in 2016).
Members of B. affinis are relatively large in size, and like other species of bumblebees, are known to be eusocial organisms. Most nests constructed by B. affinis are built underground, and are commonly found in old rodent burrows. Nests created in captivity can house up to 2,100 members, but they are typically much smaller in the wild. This species consumes nectar and pollen from a variety of plants, including Abelia grandiflora, Asclepias syriaca, and Linaria spp. The colony odor is very similar to that of Bombus terricola, which makes it difficult for predators and parasites to differentiate between the two species. Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|
More parks will be added in future updates.
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Minneapolis [Saint Paul] | 🇺🇸 United States | |
| 2 | Chicago | 🇺🇸 United States |
Rare
Under 5% of wildlife watchers report a Rusty-Patched Bumble Bee sighting in Chicago on a given day, based on 21 verified sightings from GBIF citizen-science data. It is the 473rd most-seen of the 978 insects we can rate there. Over three days the chance rises to about 10%, and over a week to about 20%, if each day is a fresh chance.
Any time of year
In every month with enough records, under 5% of wildlife watchers report a Rusty-Patched Bumble Bee in Chicago on a given day, so our monthly data shows no clear season.
2nd of 2
Of the 2 cities where we can rate Rusty-Patched Bumble Bee sightings, Chicago ranks 2nd at under 5%. The best odds are in Minneapolis [Saint Paul] (United States, about 20%).
Same genus: Bombus
The closest relatives of the Rusty-Patched Bumble Bee that you can see in Chicago (genus Bombus, Bumble Bees) are Common Eastern Bumble Bee (about 30%), Brown-Belted Bumble Bee (about 20%) and Two-Spotted Bumble Bee (about 20%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Rusty-Patched Bumble Bee is recorded against all the insects logged in Chicago (21 verified sightings), 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.
