A bumblebee with a taste for high living

Sandy, Bedfordshire A queen hit the bullseye - a 2.8cm hole in our nestbox - and there is a clearly active colony of tree bumblebees in residence

Since the start of the millennium, a new tune for summer has been spreading north. It was first picked up in Wiltshire; within a decade, it had reached southern Scotland. I can hear it from the bathroom, the bedroom, or standing under the eaves at the back door. The sound is not discernibly different from that made by the maker's nearest relatives, though the animal's habits certainly are.

We know this newbie as the tree bumblebee. Common on the continent, it flew the Channel, as wild creatures are apt to do, though we rarely understand why they choose a certain time to move. Most bumblebees nest underground. The tree bumblebee, with a taste for high living, has taken to birdboxes.