Red-tailed bumblebees are mostly coloured black, though the hindquarters are auburn red. Males feature a yellow band on their chests. Their nests are built in cairns or walls, which explains the literal meanings of their common names in various Germanic languages: "Stone bumblebee" (cf. German: Steinhummel, Swedish: Stenhumla). They are also found though in the straw of stables or in abandoned birds' nests. An average colony consists of about 100 to 200 worker bees. Red-tailed bumblebees prefer the nectar of various species of clover and deadnettle.
^Fitzpatrick, U., T.E. Murray, A. Byrne, R.J. Paxton & M.J.F. Brown (2006) Regional red list of Irish Bees. Report to National Parks and Wildlife Service (Ireland) and Environment and Heritage Service (N. Ireland).
Leisering, Horst; Michael Lohmann (1998). Großer Naturführer in Farbe (Great coloured Guide to Nature) (in German). Compact Verlag, Munich. ISBN3-8174-5229-2.