How to deal with bumblebees in your roof [UPDATED]

Bombus hypnorum

This week I’ve had two enquiries from colleagues at the University of Northampton asking advice on what to do about colonies of bumblebees that have set up home in their roofs.  In both cases these were nests of the Tree Bumblebee (Bombus hypnorum), a species that only colonised the British Isles in 2001 and has since spread rapidly (see this post from last year for a more detailed account).  Because of their association with human settlements they are significant pollinators of garden produce: over the past few weeks I’ve been watching them pollinating the raspberries in our garden and we now have a large crop.

But having a bee nest in your home is, for many people, a real concern.  I thought it might be useful to discuss the issue by quoting from the email correspondence I had with my first colleague, Paul.

Paul wrote:   I wonder if you can give me some advice. I returned home from holiday on Saturday to find that a colony of bees had taken up residence in a roof space above my front porch. The bees are not domestic honey bees but large bumblebees with white rears. I am not sure how many there are, they buzz furiously when I close the door…..  They are not in the house and I cannot see them from my loft… they are not causing a problem at the moment other than a moderate dead rabbit smell in the porch.

I am considering contacting the local council pest controllers, but fear they may just gas and kill them as they are not honey bees. What would your advice be, would it be safe to leave them alone, if so how long are they likely to stay, how large is the colony likely to become, are they likely to cause any damage or mess?

Here’s my response:   From your description they are almost certainly Tree Bumblebees which often use loft spaces, bird boxes, etc. As the name suggests they naturally nest in holes in trees. The colony is not likely to get much bigger though over the next few weeks you may find males patrolling the front of the nest, waiting for the virgin females to emerge so that they can mate. That sometimes makes the colony seem larger than it actually is – there are not likely to be more than about 150 bees in there.

I’ve had Tree Bumblebees in my roof a few times and they’ve never caused any damage. All bumblebee colonies die over the winter and the newly-mated females fly off and hibernate. So by late August or September (perhaps earlier if the weather ever gets warmer….) the bees should have gone. At that time you could seal the entrance to the roof space, though they are unlikely to return next year (although it’s not unknown).

Yes, a pest controller would kill the colony. But they are unlikely to be aggressive unless you stick your fingers in the nest hole! My advice is to let them be and take pride in your own bee colony – they are very discerning and don’t nest just anywhere 🙂

So there you have it: my advice is, leave them alone.  Of course if you or your family have a particular sensitivity to bee stings you may need to think carefully about this advice, but in my experience bumblebees are only aggressive if they feel directly threatened.  In over 25 years of field work focused on bees and other pollinators, I’ve only ever been stung a few times, and mainly by honey bees.

UPDATE: A commenter on Facebook had a great suggestion, that I provide a link to Dave Goulson’s nice little video showing what the inside of a bumblebee nest looks like – so here it is.



45 thoughts on “How to deal with bumblebees in your roof [UPDATED]

  1. Alex Laws

    I can only recall being stung by bees on two occasions in forty years. The first time was a Bombus sp. that had taken up residence in my work boot. (It probably got a worse shock than I did when my size 10 came looming towards it.) The second time I unwittingly disturbed a nest with an electric hedge trimmer. I was impressed by how they almost exclusively targeted my head, even while I was running away with my arms flailing. I wondered if it was the noise of the hedge trimmer or the physical movement that upset them, or both?

  2. Susan Walter

    We’ve just prevented a swarm of honey bees from moving in to our downstairs toilet wall via the gaps around the exhaust fan. That involved me wafting a feather duster at them for about half an hour to shoo them away while my husband ran tape around the exhaust fan to close up the gap.

    Last year white-tailed bumble bees (B. lucorum) nested in our barn. I was a bit surprised but just left them to it.

    I’ve always been puzzled by the lack of tree bumbles here in central France. I’ve only seen one once, in a friend’s garden. We get all the other usual suspects.

  3. Little Red House

    Hi Jeff I read this because it was shared by Stanwick Lakes Facebook page. We live in Thrapston and have a similar problem in our ‘man cave’ roof but with honey bees. We had a local keeper come out but she was unable to move them because they had nested inside the roof cavity (we can’t see them from inside the ‘cave’). The keeper gave the impression that the only way to move them us by killing them, does that sound right? They were quiet over winter but they are now active again. They aren’t bothering us at the moment but in future we’d like to replace the roof. I really don’t want to kill them obviously!
    Many thanks,

    1. jeffollerton Post author

      Hi Melanie,

      Yes, if the bees are not easily accessible then killing the nest would be the only way to remove them. However it’s quite possible that the colony will only be active for a few years, after which you could replace the roof.

      The other option would be to replace the roof when the colony is dormant in the winter, though warn the roofing company that you want them to work around it if possible.

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    1. jeffollerton Post author

      Just to be clear, as far as we are aware this bee was not introduced by people (either accidentally or on purpose). That has been speculated upon in the literature but there’s no evidence to support it. As far as we know it’s a natural range expansion. Check out Dave Goulson’s review of invasive bees in AREES from the 1990s (?) and see who is citing that.

      1. standingoutinmyfield

        Yep! That’s one of my primary references…I’ve already collected over a hundred. I was just wondering if there was anything specific about this species, as I haven’t found anything in the literature yet.

      2. jeffollerton Post author

        Yes, but Catherine and Mark cite no evidence that it has been introduced by humans, they are just assuming that’s the case. We can get into a long debate about what “native” and “non-native” actually means, but I think they jumped the gun with this paper.

  5. Greg McLeod

    We used to give similar avice but these days recommend removing and relocating if possible. Main reason for this is that they can become quite nasty and aggressive at certain times within the nest cycle. We also regularly see evidence of them going thru 2 possibly 3 nest cycles. These days I doubt we are doing the right thing by relocating the nest as I believe that in the future it will be proved that they are having a detrimental effect on our native species of pollinators, as it has been proved similar about honey bees by some researchers.
    We discussed this a couple of years ago with a leading professor studying bees and he felt that the poisoning of these Tree bumble bees was fairly inconsequential in the scheme of things.
    In the meantime we carry on relocating Tree bumblebees where possible, we also specialise in the removal and relocation of honey bees in roofs and chimneys for further info

    1. jeffollerton Post author

      Hi Greg – thanks for the comment, it’s interesting to get the perspective of someone at the sharp end (so to speak!) of dealing with the bees. Speaking as another “leading professor studying bees” (:-)) I think I’d generally agree that killing off the colonies won’t do much harm to total population size of Tree Bumblebees, as it wouldn’t for any other common bee. However I disagree that we should think of Tree Bumblebees as not native: all the evidence that I have seen suggests that this is a natural range shift by the bees. They are also moving eastwards on the continent. Species do that, they don’t always have fixed ranges; for example Collared Dove was unknown as a breeding species in Britain prior to the 1950s. There seems to be enough nectar and pollen available in gardens to allow Tree Bumblebees to coexist with the other species, and they don’t generally compete with the other bees for nesting sites, so my prediction is that they won’t negatively affect the other pollinators. But only time will tell.

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  7. Beverly Thompson

    Thanks for all you advice on here….I can see white tailed bees going into my roof space in the back extension. The boiler pipes go up there and it gets hot but I did find a bee in here the other day so I’m going to seal the pipe holes above the boiler. I’ve tried for ages to save and help the bees so I’ve asked my husband not to spray the loft, just to leave them and wait til September to seal it. I suppose I am helping them big style by providing a nesting place now. It was wasps on the opposite end last year…….and they got sprayed! So glad I read all this.
    Beverly, Lancashire UK

    1. jeffollerton Post author

      Thanks for the comment Beverly, glad you found this useful. Yes, I’m sure you’ve helped your local bees by giving them a place to nest. As for wasps, they can be really important pollinators too, especially late in the season for ivy. And of course ivy berries are important food for birds during the winter. The points I made in this post from last year apply also to other types of wasp:

      In my experience honey bees are far more aggressive than wasps!

  8. Gerry

    I have had 2 colonies of bees in my loft for many yrs and I’m very proud to say I have i can watch them from 6ft away from inside my home from my window without disturbing the beautiful geniuses.

  9. Max_B

    Useful information, thanks. I too have had bumblebees set up a nest in the roof of my bungalow this year – for the first time – and wasn’t sure whether I should do anything about them. But you seem to suggest they will leave later in the year, so I’ll try leaving them alone. Being a bungalow, the roof is low, so they do dance around at head and chest height and get in the way a bit. They look more like a Tree bumblebee.

    The smaller ones don’t seem to go very far, just dance around a lot in the air outside the nest opening in the eves, where as the big noisy ones seem to be very purposeful speeding straight off into the distance when they leave the roof, and disappearing quickly inside again upon their return. I’ve found 3-4 dead bodies of quite small ones on the ground in the area of the nest, although these don’t seem to have the whitish tail of the ones which are flying.

    1. jeffollerton Post author

      Thanks for the comment Max. Yes, they should disperse later this summer. The small ones are males, waiting for the newly emerged females to leave the nest.

  10. Ruth

    We came home after a weekend away to find about 30 dead bees in our bathroom. We had no idea where they came from. We went outside and noticed a lit of bees flying over the chimney. We now suspect a bee hive in the chimney. We noticed them coming down the lights. We now blocked all the lights so they cannot come down from there however when we came back from being away a night we found again 30ish dead bees. No idea how they come down. What can we do?

    1. jeffollerton Post author

      Hi Ruth – there must be some other entrance into the bathroom that you have missed. Would be worth sitting in there with a cup of tea and a good book and see if you can work out where they are emerging from. Are you able to keep a window open in the bathroom so that the bees can escape? The good news is that the colony should disappear at the end of summer.

      1. Ruth

        That is good news. We have a toddler and want to keep him safe. Both windows are wide open however the bees we noticed, seem dopey when they come down and cannot find the way out. We have sat in the bathroom and there is a spot they seem to ‘fall out off ‘. It was weird to watch. We have not spotted a hole in the ceiling but there must be one. Thank you for your reply.

      2. Tamsin

        Hi Jeff

        We think we might have a tree bumblebee nest in our sloping bedroom ceiling. We can see the bees coming and going through a gap between the window frame and roof tiles, and also hear them from inside. They’ve been there about a month and we can hear them buzzing and making noises particularly at night. We’re in the Rutland area.

      3. jeffollerton Post author

        Hi Tamsin – yes, sounds like that’s what you have. They are quite choosy and don’t just pick any old house to move in to – enjoy! Happy World Bee Day – Jeff

  11. H J.

    so interesting, heard some strange noises in the soffit space outside our toilet window over a few nights, thought we had sparrows nesting. Having found some dead bees outside, orange thorax black back and buff tail, believe they are tree bees bombus hypnorum. Over last week larger numbers of bees found entering under the edge of a roof tile, some quite large what I would call “bumble bee size” and others “wasp” size. From what I read I am happy to leave alone and get the roofer back on a good winters day to sort the tiles. We are on the coast in Carmarthenshire.

    1. jeffollerton Post author

      Yes, they certainly sound like tree bumblebees form your description. Even in a single colony they can vary a lot in size so that might be what you are seeing.

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  13. Michelle iley

    Bees have moved in to dorms window space and it’s driving me insane. I keep imagining them getting through the wall and I can hear them. They won’t shut up it’s like the sound of geese through the wall or a marching band with gazoos. Do they ever sleep?

    1. jeffollerton Post author

      Sorry to hear that Michelle. Bees probably don’t sleep the way we sleep, but they certainly are much less active at night. My wife swears by silicone earplugs to block out night time noises (including my snoring!) – don’t know if that would help? Best wishes, Jeff

      1. Helen

        We have a nest of what I think are tree bees in our roof, we are leavig them to it but I am finding more and more dead on our driveway 😦 why could this be?

      2. jeffollerton Post author

        Hi Helen – it’s possibly because birds such as blue tits enjoy eating them! They will often catch the bees, fly to a perch nearby, then eat the honey-stomach inside the bee and drop the rest to the ground. Gruesome but all part of life’s cycle 🙂

  14. louise

    We have tree bumble bees in our roof. Does anyone know if they’re likely to be in the loft space and if it’s safe to do some work up there? We have a plumber due to work on pipes in the loft soon.

    1. jeffollerton Post author

      Hi Louise – they are unlikely to go into the loft space itself, but you should warn the plumber to watch out for them and not to disturb their nest, just in case.

  15. Norma Cameron

    I have noticed a few dead or slow moving bees outside on the ground & after looking up noticed a lot of activity around eaves of the roof. We are quite happy to have the tbbs as lodgers but sad so many are falling/dying. Is there anything I can do to help them? We will just keep an eye on them & leave the nest as they’re not bothering anyone & so far haven’t got in the dormer window:)

    1. jeffollerton Post author

      Hi Norma – it may be that these are older workers and male bees that are coming to the end of their lives. They only live for a few weeks. Glad to hear that you are enjoying having your own tree bumblebee nest in your home 🙂


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