by Skip Via
skip@westvalleynaturalists.org

As an aspiring bee person, I try to keep close tabs on the different species of bees that I come across in the valley and environs. When a new-to-me species comes along, I try to find out as much about it as I can. In that regard, for the past week or so I’ve observed a large, distinctively marked species hanging around various flowers in my yard in fairly strong numbers–several can usually be found feeding on the bee balm near our deck, as seen in these photos.

It turns out that this is a white shouldered bumblebee, native to the Pacific Northwest as far east as the Rockies, into southern British Columbia, and as far south as southern Utah. It’s not uncommon or endangered like some of our native species (see A Very Special Bumblebee on this site), but it’s generally found at higher altitudes, preferring montane meadows and grasslands. It is said to be one of the least common bumblebees to show up in developed areas, which may explain why I’ve never observed them here. But why they’ve suddenly shown up here in large numbers is a bit of a mystery.

Their food of choice is delphiniums, which agrees with my observations here, but like most native species they will happily go to a wide variety of plants, pollinating as they go. They are ground nesters, either underground or on the surface.

Has anyone else seen white shouldered bumblebees locally? Let me know…