The Tree Bumblebee, Bombus hypnorum, seems to be doing very nicely. They’re called Tree Bumblebees as they nest above ground – in tree hollows or, more obviously, in unused bird nest boxes. This makes them more noticeable than our other bumblebees, which typically nest in old mouse nests or similar underground sites. Compost heaps can be a favourite for Carder Bees, too, which can be rather more irritating than a bird box!
Helping on the Bumblebee Conservation Trust stand at garden shows over the last couple of years it’s apparent that people are noticing the Tree Bumblebee more and more. They tend to be a bit more aggressive than other bumblebees (which isn’t saying much!), with several whizzing around their nest – as pictured – and others looking like guard bees at the entrance to it. They’re easy to spot when they forage as they’re pretty distinctive – they’re ginger (head), black (thorax) and white (bottom). Despite their being short tongued bees they seem to be very adaptable, foraging on a wide range of flowers.
What’s nice about Bombus hypnorum is that they’ve only been here since around 2001, when they hopped over the Channel and were spotted in Wiltshire. I would guess they’re now one of our more common bumblebees, despite some folk still claiming they’re a rare new import. Nevertheless, I was still chuffed to find a colony in our back garden in an old bird box, behaving very typically.
They’re an interesting illustration of the constant change in our flora and fauna. The Tree Bumblebee seems to be drifting north like other bumblebees, probably as its traditional range is getting too warm. As far as I’m aware Bombus hypnorum doesn’t do any harm, so it’s a benign “non-native” and a distinctive addition to our wildlife. Vive la difference!