Endangered Species
Midwest Region



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Rusty patched bumble bee

Rusty Patched Bumble Bee (Bombus affinis)

Status: Endangered


Listing as Endangered Effective March 21, 2017

The listing of the rusty patched bumble bee as endangered under the Endangered Species Act became effective on March 21, 2017. The final rule to list this bumble bee published in the Federal Register on January 11, 2017 with an effective date of February 10, 2017. The effective date was subsequently extended to March 21, 2017. 


Species Profile with Map of Current Occurrences


Guidance for Project Reviews and Surveys

The rusty patched bumble bee is likely to be present in scattered locations that cover only about 0.1% of the species’ historical range.  It is within these limited areas we recommend that federal agencies and others consider the need to consult with the Service on the potential effects of their actions or the potential need for an incidental take permit under section 10(a)(1)(B). For the remaining 99.9% of the historical range, we advise agencies and others that this bumble bee is not likely to be present and that consultations or incidental take coverage is not necessary. 


We prepared guidance to help federal agencies and project proponents make a quick and accurate determination as to whether any project location may overlap with an area where the rusty patched bumble bee is likely to be present and, if so, how to conserve the species and meet ESA regulatory requirements.


Guidance on Endangered Species Act Implementation


Final Rule to List as Endangered

Just 20 years ago, the rusty patched bumble bee was a common sight, so ordinary that it went almost unnoticed as it moved from flower to flower, collecting nectar and pollen. But it's now balancing precariously on the brink of extinction and has become the first-ever bumble bee in the United States -- and the first bee of any kind in the contiguous 48 states -- to be declared endangered.


What you can do!


Grow flowers, including flowering trees and shrubs. Have a mix with something in bloom from early spring through fall. Include native milkweeds for monarch butterflies.


Bumble bees and many other pollinators (bees, moths and butterflies) need a safe place to build their nests and overwinter. Leave some areas of your yard unmowed in summer and unraked in fall, in your garden and flower beds leave some standing plant stems in winter.


Provide a pesticide free environment.


Bumble Bee Conservation by the Xerces Society for Invertebrate Conservation


Find out more »


The endangered designation means that the rusty patched bumble bee is in danger of becoming extinct throughout all or a portion of its range. Service Midwest Regional Director Tom Melius said, “Our top priority is to act quickly to prevent extinction of the rusty patched bumble bee. Listing the bee as endangered will help us mobilize partners and focus resources on finding ways right now to stop the decline.”


Once common and abundant across 28 states from Connecticut to South Dakota, the District of Columbia and two Canadian provinces, the rusty patched bumble bee has experienced a swift and dramatic decline since the late 1990s. Abundance of the rusty patched bumble bee has plummeted, leaving only a few small, scattered populations in 9 states and one province.


News Release


Final Listing Rule: Federal Register January 11, 2017 Adobe PDF Icon


Literature Cited in Final Rule


Questions and Answers


Rusty Patched Bumble Bee (Bombus affinis) Species Status Assessment Adobe PDF Icon (June 2016)


Fact Sheet


Life History

Excerpted from the Final Listing Rule

Excerpted from the Species Status Assessment


Current Range: IL, IN, IA, ME, MA, MN, OH, VA, WI and Ontario, Canada


Have you seen a rusty patched bumble bee?

Bumble Bee Watch - Bumble Bee Watch is a citizen science project to track and conserve North America’s bumble bees. The site provides useful identification information.



The Rusty Patched Bumble Bee: the story of a declining pollinator links to the Xerces Society


Archives - Chronological list of previous Federal Register publications and associated information


Species of Concern

Midwest Endangered Species


Last updated: March 20, 2017