Its not only birds that use bird feeders! Bumblebee hibernation or ‘sleep over’ site?

Early September I was out in the garden when I saw bird seeds falling to the ground from a bird feeder next door. I looked inside it to find a queen tree bumblebee, Bombus hypnorum, busy digging away inside and flicking the seeds out. I know they will ‘steal’ bird nest boxes, but steal their food as well would be taking it too far!! I gently removed her and she fly away. I carried on with the gardening, thinking it was a one off and I did n’t have my iPhone with me to film anyway!

Lo and behold a few minuted later I saw the seeds being scattered. Removed her again and yes a short while later saw exactly the same behaviour. I decided to film it. I suspect she was looking for a possible hibernation site or an overnight site and digging around as an exploratory dig. Five times I removed her and after this sixth time and being filmed, she never returned! What was she doing there?

Whilst filming, typically she did not flick any seeds out this time, just rested!

Potential hibernation sites?

I receive many reports of bumblebee activity and increasingly people are finding tree bumblebees hibernating inside hanging baskets, when they come to take them down or empty them. Perhaps this queen was exploring the seed feeder as a potential hibernation site? Most bumblebees that nest on or near the ground in soil/dead leaves/compost bins excavate a small tunnel in the soil on of near the ground in which to  hibernate. Perhaps tree bumblebees, which nests higher up in tree holes, bird boxes, roof spaces etc., may therefore look for a hibernation site higher up? A vertical hole with soil like material easily dug into and moved around could be an exploratory hibernation site dig? In this case the seeds represented soil as she dug out a small chamber? This could well be an area of research for researchers. Finding wild bumblebee queens hibernating is very difficult and this may be a way of attracting queens to hibernate and be monitored?

For more information about bumblebees see The Bumblebee Conservation Trust

Check out the BTO Garden Bird Watch site, you may find other unusual behaviour from other wildlife in your garden!