Buff-tailed Bumblebees

They may have been seen occasionally on warmer winter days, but March is the real start of the flying season for many bumblebees and the one you are most likely to see in your garden is the Buff-tailed Bumblebee. As you might guess, it can be recognised by the buff-coloured tip of their abdomen, they don’t actually have a tail.

Generally, colonies of bumblebees die down in autumn with just the queens over-wintering to start breeding a new population of workers in the spring, but here in Devon some of the Buff-tailed workers can also survive the winter, feeding on winter flowers such as Mahonia and Camellia, and so the colony has a good start to the year.

Buff-tailed Bumblebees usually nest underground in old rodent burrows. At their peak these nests can contain up to 600 workers. If the nest has a fresh start in spring the new workers appear approximately six weeks after the nest is established. The nesting period typically lasts three to four months, when new queens and males will emerge. This allows this species to have two nest cycles a year, and you can still find them in the garden as late as the end of September.

The queen is black and yellow but has a buff-coloured tail, which is distinctive amongst the UK bumblebee species, although there is a White-tailed Bumblebee. Rather confusingly, workers and males have a white tail, although there may be a narrow buff band at the base. There are several other black and yellow bumblebees, but they have different colours and locations of the yellow bands; Buff-tailed have golden yellow bands at the front of the thorax and across the middle of the abdomen.

Buff-tailed Bumblebees feed on a variety of flowers but have relatively short tongues and they can struggle to reach the nectar of long, tubular flowers. Nothing if not resourceful, they have developed a method of extracting this energy-rich nectar from inaccessible flowers, through a process called nectar robbing. They visit the base of the flower and bite a small hole to gain easy access to the sweet substance. This doesn’t help the flower to have its ovules pollinated, but it is not thought to be a major hindrance to the plants.

Many bee species, and other insects, are having a hard time at present with loss of habitat, increased use of pesticides and changing weather patterns all having an effect, but help being given by gardeners seems to be working for the urban populations of the Buff-tailed Bumblebee.

Apart from the birds, volunteers from the British Trust for Ornithology’s Big Garden Birdwatch have also been able to record Buff-tailed Bumblebees, and other invertebrates for nearly two decades. Last year was a disaster for butterflies according to the results of the Big Butterfly Count, but the records show that in 2024 the number of Buff-tailed Bumblebees recorded was higher than the average across all years since records began. There could be a number of reasons for this disparity.

It is thought that the butterfly population was hit by the cold wet spring reducing the number of caterpillars that made it to adulthood. The cold wet spring will have slowed the development of the bumblebee colonies but the queens will have survived to take advantage of the warmer spells later in the year. Also, many of the butterfly counts were out in the countryside where habit changes are having their biggest impact. The BTO data is just in gardens where positive human efforts to help pollinators in general and bumblebees in particular are at their greatest.

If you do try to help pollinators in your garden, keep up the good work because it is helping one of our most loved species, the Buff-tailed Bumblebee.