By Gavin Ramsay
Have you seen any bumble bees recently? One of our most-loved bumble bees, the buff-tailed bumble bee, Bombus terrestris, has been trying out a new strategy lately. Instead of waiting for a warmish spell in February to April to come out of hibernation, some queens start new nests in late autumn or winter and both queens and workers can be seen on the wing, collecting forage for their nests, with drones possible too. In the southern half of England people have noticed for a few decades some bumble bees foraging on winter flowering plants such as Mahonia, winter honeysuckle, winter heathers and Viburnum x bodnantense. Another species thought to be doing this is the early bumble bee, Bombus pratorum. These winter-active nests seem to have become more common and have now been recorded further north into Scotland with one bee recorder seeing bees in Edinburgh on New Year’s Day this year (see picture). It has been speculated that it is our gardening activities that have permitted this change but Steven Ewing’s observations of at least three individuals of buff-tailed bumble bees on Corstorphine Hill were on gorse. Why they should indulge in such risky behaviour is not really known but one benefit they may get is avoiding the cuckoo bees which can be a large drain on the productivity of populations.
As this is being written, we are in a long cold spell with few opportunities for foraging so it is possible that such nests will fail this year. If you have spotted a bumble bee foraging this winter, was it before or after this cold spell? Queen buff-tailed bumble bees are easy to identify: huge bees with the classic two yellow stripes and a buff-coloured tail rather than the off-white of her workers and of the later and smaller queens of Bombus lucorum. Bombus pratorum queens are smaller still and fast-moving bees with a peachy tail. Do share with us any sightings and please do also record them for a special project run by BWARS.