For many years I have had a nest box on the side of my house, which has been occupied each year by blue tits that have successfully raised broods. This year, I was weighing up the task of re-painting the barge board nearby and noticed the nest box did not appear to be occupied.  I was safe to proceed with my painting. However, as I was putting the ladder in place, I inadvertently tapped the box and was rapidly greeted by a mass of bumblebees – time for a sharp exit – the painting can wait!

On further investigation I was delighted to identify the bees as tree bumblebees and have enjoyed finding out about them and watching their daily activity. It is quite normal, and I would say entirely reasonable, for them to exhibit defensive behaviour when the nest is knocked, and they soon calmed down once I removed the ladder.

The tree bumblebee has a natural distribution of mainland Europe, Asia and up into the Arctic Circle. It has only relatively recently arrived in the UK with the first record being in 2001.

Since its arrival, the tree bumblebee has spread rapidly reaching as far as Scotland by 2013. Its arrival is a welcome one as it hasn’t been found to harm our native species of bumblebees, or other wildlife, and at a time when our native bumblebees are declining, this very effective pollinator has stepped in to offer a helping hand.

This bumblebee is a woodland edge species, but readily adopts man-made structures for nests such as loft spaces and most commonly bird boxes. This tendency to make use of man-made structures may account for their rapid spread through the nation’s gardens.

I have really settled into watching the bees as I walk past each morning and love seeing them visiting flowers in my garden. The gooseberry crop looks particularly promising this year which I am sure has been helped by tree bumblebee pollination. They are very industrious, flying to and fro’ throughout the day.

A climbing rose next to the box has recently provided them with a very local nectar and pollen source – encouraging them to ‘shop’ locally and it is a real joy to sit on the seat below their nest and listen to the buzz and breathe in the scent of the rose. A very therapeutic ‘lockdown’ activity and the epitome of spring and summer. I shall miss them when they leave.