'Help... there's a swarm of bees in my bird box!'

I'm getting LOADS of messages and emails this week from people who have noticed 'Swarms of bees in bird boxes'..... also under the eaves of houses and other unexpected places.

These will be Tree bumblebees Bombus hypnorum.

Please don't call out the pest control people!!! The nest has already been there, possibly unnoticed, for at least a few months. The reason for the sudden increased activity is that this is the time of year bumblebee colonies produces new daughter queens. The local males (who have already left their own nests) become very excited and congregate outside the nests where new queens are about to emerge.... in the hope that they can mate with them.

The males dance frantically around the outside of the nest (which is very often in an old bird box, a hollow tree, or under the eves of a house) giving the appearance of a swarm.

Don't worry; this will not last long. It just means the colony has been successful and is now approaching the end of its life-cycle.

The new queens will soon leave the nest, mate, stock up on pollen and nectar, and go into hibernation till early next spring. The old queen, together with all the remaining workers and the males will not survive for longer than a few more weeks.  If you clean the box out over winter you are more likely to get birds nesting in it next year than bumblebees.

Tree  bumblebees are the ultimate opportunists. I have seen the nesting in old canons, tumble dryer outlets and letter boxes. I also watched a nest thrive last year in a muck spreader that a local farmer was still using to spread muck at least 3 times weekly. He got stung a couple of times whilst attaching it to his tractor, but took it on the chin (literally) and generously decided not to evict them

So, enjoy and celebrate the fact that you have provided a home for these bumblebees!

A final word of caution. The female guard bees are on high alert during this period and a little more defensive in their behaviour than usual, so stay away from the nest whilst the males are dancing outside.... and be aware that they seem to become especially defensive, and occasionally aggressive, if you use strimmers or lawnmowers nearby.

And please submit a record of your sighting here...  TREE BUMBLEBEE SIGHTINGS

Loads more excellent info about tree bumblebee nests (and how to move them if you really need to) here... Reigate Beekeepers