November was once the quiet season for bumblebees. By mid-autumn, most colonies had died away, leaving only newly-mated queens tucked into soil or leaf litter to wait for spring. But across the UK, and most noticeably in the south and in towns and cities, the gentle buzz of bumblebees now lingers well beyond summer.

Since the 1990s, sightings have shown that buff-tailed bumblebees are breaking from their usual seasonal patterns. Rather than entering dormancy, some queens are setting up nests in autumn, producing workers, males, and even mating pairs during a period when bumblebee activity was once virtually unknown. This remarkable shift is one of the clearest insect responses to our warming climate.

Why is this happening? Milder winters are a key driver. Warmer temperatures allow queens to remain active instead of entering their dormant phase, while towns create a micro-climate known as the Urban Heat Island effect, keeping city habitats warmer than surrounding countryside. Urban gardens, parks and amenity plantings also provide something essential: winter flowers. Species such as mahonia, winter honeysuckle, heather and even late-flowering ivy now supply nectar and pollen at a time of year when wild forage was once scarce.