The tree bumblebee (B. Hypnorum) is a recent addition to the UK’s fauna. Despite this it will already be familiar to many householders as it can be the cause of most of our phone calls at this time of the year “Help I have a wasp nest”! Callers may have seen a small ‘swarm’ of several ‘dancing’ bees outside the nest hole which can be in a bird box or high up in property eaves. Sometimes bee chatter/activity can be heard through the ceiling if the nest is in the eaves.
See this excellent video of ‘dancing’ tree bumblebees from the Bumblebee Conservation’s website
Colonies formed in the spring usually decline naturally by late July, if not sooner.
So unless you’ve been on Mars for the last decade, you will know by now that Britain’s pollinating insects are in trouble, and bumblebees are no exception. You are lucky that these first-class pollinators have chosen your house! Enjoy them and let them do their beneficial job.