Field Identification overview

The focus of this bumble bee identification effort is on females: Queens, workers and Cuckoo queens.

In some species the male/drone does not resemble the queen/worker at all. Male bumbles as a whole can be a challenge. As we learn more we will expand the information on our site for male bumble bee identification.

Field identification of bumble bees is more challenging than it seems like it ought to be, if you started as a birder. If you started with plants, fish or invertebrates you may be able to guess some of the hurdles.

While color patterns may seem obvious when you are looking at a live individual buzzing around your garden or native wildflower, when you go back to most published bumble bee guides you will see that a given species of bumble bee (genus Bombus) may have several strikingly different color morphs–with no indication of which color morphs occur in what parts of the range–as well as differences between queens, workers and drones.

As an aside, that is why this blog is being created, to help reduce the “noise” around all the various color patterns that a given species may exhibit–by narrowing the geographic range to Washington state.

As a starting place, within Washington state, most bumble bee species only have one, or maybe 2 color morphs. There are a couple of outliners in this regard however. More to come.

Confirm it is a bumble bee

To identify a bumble bee, start by confirming it is a bumble bee. We don’t mean this sarcastically, rather there are some surprisingly good bumble bee mimics around that make one second guess.

Both of the individuals above meet many of the criteria for a standard bumble bee: relatively large body, furry, color on the abdomen, and a black band between the wings.

What they don’t show is any evidence of a corbiculum (although male bumbles and cuckoo bumbles don’t either) nor long antennae.

The corbiculum is a flattened area on the rearmost (tibia) leg that enables a female bumble bee to collect and transport pollen back to the nest. If you can see pollen on the rear leg, you know the individual is a female (queen or worker). All male bumbles and cuckoo queens lack a corbiculum.

Even if the bee has not yet collected any pollen, the flatten area of the rearmost leg is often visible. It may have hairs along the flatten edges, but the flat surface itself is smooth–or covered by collected pollen.

Males and cuckoo bumble bees have more rounded and hairy legs. Legs on some males may seem to imply a flattened corbiculum, but on closer inspection the area will be hairy not smooth.

For each species discussed there is a species page.

The species page contains some standard elements:

  • Photos from various angles
  • Photos of different color morphs, as needed
  • Map of past detections (2016, USDA NPID data)
  • Species specific identification tips
  • Similar species photos, as needed

When a species has multiple color morphs in Washington, we have tried to include both the most commonly encountered variety, plus other varieties and the parts of the state where those variations are most likely to be encountered.

Species identification tips come from notes (DJ) taken at a lecture done by Rich Hatfield of the Xerces Society, from the publication Bumble Bees of the Western United States, by Koch, Strange and Williams, and from our own field experiences.

Efficient field ID is all about narrowing down the possibilities.  When birding, try to determine for example hawk vs hummingbird.  A lot fewer possibilities in either of those categories compared to all the birds that can be seen. 

There are at least two complementary approaches to narrowing down choices for field identification. One is expected range: is the species you think you see likely be seen where you are, based on what others have reported. What species are likely to be encountered in a given area?

The second is coloration. Rich Hatfield pointed out the same principle folks use with birds and fish could just as easily be used with bumble bees, using color patterns.

This site starts with the structure Rich articulated but has been modified to cover more species and the order of the categories was shifted from a web flow perspective.

For each species covered, we have added characterizations to the species posts showing the decision elements present.

Washington's bumble bees

Bumble Bees of Washington State

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