WHEN BEES TAKE OVER YOUR OWL BOX

Posted November 5, 2018
by Hilary

owl box of bees

Where I live, in Southern California, it’s common for wild bee swarms to move into unconventional spaces. They particularly favor owl boxes. These man-made wooden boxes, hung high in a backyard tree, are an ideal nesting location for honey bees. Many homeowners are not aware of this potential when setting up their owl boxes and end up with a bit of a mess on their hands when the bees choose to takeover. I get dozens of calls about this very situation every year. Read on to discover everything you need to know about bees and owl boxes.

Why Are Owl Boxes Attractive to Bees?

In spring and summer honey bee colonies produce swarms. These groups of bees are new colonies in search of a place to establish a new nest. Bees like to live in cavities of certain volume and most owl boxes fall in this size range. In fact, beekeepers who hope to attract wild swarms build “swarm trap” boxes out of plywood that very closely resemble owl boxes and often hang them in trees. Bees like to nest high off the ground, away from most predators. The main difference between an owl box and a swarm trap is the entrance size. Generally, bees prefer small entrances, an opening about the size of a quarter, but they can make due with a larger entrance. Owl box bee colonies usually close up most of the entrance with a substance they make from tree resins, called propolis. They use propolis to create a barrier that reduces the entrance size. Bees also choose locations where they are close to flowering plants and have access to a water source. Chances are, if you are setting up an owl box, you are already a supporter of wildlife and probably have these other two features on your property as well!

Bees in owl box

How to Keep Bees Out of Owl Boxes

It’s difficult to compete with the natural nesting instinct of swarming bees. Realistically, you may not be able to keep them out of your owl boxes, but there are a few things you can try. For example, some claim that if you spray the inside of the nest with WD40 the smell will repel bees, but the owls won’t mind. Personally, I have not tested this claim, but the reasoning is sound on the side of bees. Bees are sensitive to smells and I can definitely believe that they would avoid nesting in a location with an overpowering smell like WD40.

Another tactic involves embracing the incoming swarm, but providing an alternative nesting site. The idea is, you set up a more attractive box for the bees to live in and they will go to that and leave your owl box alone. You can accomplish this easily, by creating a replica of your owl box, only with a small entrance instead of a large one. At this point, you might wonder, “Won’t this attract bees to my property”? The answer is, “Yes”, but if you plan to set up an owl box, you are already attracting bees to your property. Now, not everyone wants to be a beekeeper or host a colony of honey bees in their yard, but if done properly, you can attract the bees to a box that  is more convenient to remove than your owl box would be.  If the box is on the ground and easy to access, it will be significantly less expensive to have them removed by a live bee removal company… you may even find a hobbyist beekeeper who will come take the bees away for free.

Probably the best way to keep bees out of your owl box is to use both these techniques. Repel the bees with a strong scent in  the owl box and attract the bees to an alternative nesting box on the ground. Make sure you clean out the alternative nesting box at the start of each spring. A swarm might decide against moving in if it’s full of spiderwebs.

Bees in Owl Box

The Problem with Bees in Owl Boxes 

A colony of bees might be a welcome thing in your yard, especially if you have fruit trees in need of pollination, but while owl boxes might be an agreeable location for the bees, it could still cause you problems. The biggest issue with letting bees live in owl boxes is the height and weight. Over time, honey bee colonies can grow very heavy. Depending on how much space they have and how much is dedicated to honey, an owl box full of bees can be over 100lbs. This makes them very difficult to get down, should there ever be a problem, but if you have them removed right away, their weight will be much less. A newly arrived swarm may be less expensive for professionals to remove because it will be a little easier to do. Additionally, you have a better chance of finding a hobbyist to do the job for free, but you should take the risk and liability of this situation into consideration… a hobbyist is unlikely to be insured.

Here’s a video of a recent owl bow removal I did. The box wax extremely heavy and nearly 25ft up. We had to rent a ladder that would be tall enough and rig a pulley system to get them down.

 

Risk of Falling 

If you decide to leave the bees alone and your owl box is not attached to the tree securely enough for that weight, the whole thing can fall down in a storm, creating a sort of “bee bomb”. I have seen a have owl box full of bees bend the metal pole it was mounted to in its fall to the ground. If your owl box falls, now, you must deal with an angry fallen hive in a hurry and this could be costly to resolve if no hobbyist beekeepers are available on short notice.

Tree-trimming 

Some people allow bees to stay in the owl box without considering that they will need to eventually trim their tree and tree-trimmers will not work on a tree that has a colony of bees in it. Honey bee colonies can live for decades with the right conditions. If you let the bees establish, don’t count on them leaving any time soon. When a colony swarms, only half of them leave. The rest stay behind and continue to live and work in the existing hive.

No Owls

This seems obvious, but if bees move into your owl box, you won’t get any owls! It’s also worth noting that bees will occasionally chase nesting owls out of the box if they have no better alternative, sometimes killing the fledgling owls in the act.

My Recommendations 

If you choose to set up an owl box, be prepared for the likelihood that bees will take it over. You should not only use a repellant and set up an alternative nesting box, but you should set up your owl box so that it can easily be taken down. Here are some things to consider:

  1. -Select a tree  that is easily accessible by ladder, with a clear path through the branches and a flat area at the base of the tree.
  • -Place your owl box at the minimum recommended height.

-Make sure the own box is well sealed, with no cracks or gaps. When a beekeeper comes to remove the owl box full of bees, it will be easier for them to do if the box has no gaps for bees to escape. That way they only have to worry about closing off the owl entrance.

  • -Design the owl box so that it can be removed from the tree without opening up any part of the nesting cavity. Use exterior mounts like brackets or eye hooks for hanging. You want the beekeeper to be able to detach the box from the tree or structure without having to open the roof to unscrew a nut that is on the inside of the box or anything of that nature.

-Once bees have lived in your owl box, their scent remains and will continue to attract to bee colonies even if you have had them removed. Therefore, you do not want to keep your owl box after bees have moved in. Let the beekeeper have it.

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7 Comments

  1. Mark REEVES

    Hi Hilary

    I really enjoy your your posts and learn so much from the helpful information, thank you.
    Can I ask for some advice please

    I have a wild colony of bees in a possum box very like your owl box.
    I can get the box down from the tree ok but how do you think is the best way to transfer the bees into a Langstroth hive.? I have a hive of bees that swarmed from the Possum box mid spring and they are doing really well. I am new to beekeeping and really love it.. I have a real love of nature and have an organic garden and small veggie patch, pond, and very lucky to live in the county with lots of flowering gum trees. The ???? seem to like it here.
    Any advice would be greatly appreciated, thank you in advance.

    Have you written a book on bees or can you recommend one.

    Kindest regards

    Mark.

    Reply
  2. Sean

    I’m fighting this condition right now. I have a screech owl box which has been successfully used for three years and enjoy them being around. Just yesterday I notice about 20 or bees going in and out and the owl was flying back an forth from the box in the day as if it was looking for help.
    No disrespect to bees in general but I can’t imagine the owlets getting mascaraed …..So in the evening i opened the top of the box to peak in and there are 4 eggs there and while i did not stare around I also could not see any bees or hive. I thought to myself I got them all. Well the next afternoon they were back. When i sprayed again the owl flew out too. So she did returned that night and i desperately want to save those owlets. Any further help would be appreciated.

    Reply
    • Sean

      Me again. I may have useful tip. I spoke on the phone with someone from our local bee keepers association. He was very patient and described exactly what was happening to me as if he was right on my property. He said the bees, sometimes 5, sometimes 10 were scouts looking for a suitable place for a new hive. He went on to describe that there is a vote in process at the moment. These scouts are going back and forth from my owl box and to other potential location(s) and then back to their hive to vote on which location would be the best to colonize !
      He went on to say that if enough of them they vote to use my owl box, then i will have an issue and the owls will be done for. If they vote to go elsewhere, they will simply be gone. At least for this spring. He said it was good fortune that spotted this activity and my best course of action was to immediately open the lid of the owl box and stop killing the scouts. He beelives that when the owl box lid is open it will become less attractive to them and the vote will be lopsided enough that they will go to the other location.
      I opened the lid and propped it with a stick as instructed. I then watched for almost an hour as the bees came in groups 4 -5 at a time. They flew in and out of the box and then left. Then as time went the groups got smaller 2-3 at a time, 1-2 at time and after an hour, nothing ! Just as he described would happen.
      When it start to get dark I went back up the ladder to remove the stick, this time with my phone to take a picture of the 4 owl eggs. As I carefully removed the stick and peeked over the top there was the momma screech owl staring back at me ! Great ! She was back and I didn’t even notice her sneaking in, she was watching the whole time, of that i’m certain.
      Now I”ll watch again tomorrow and reopen the lid if the bees still have not finished they polling process.
      Hope I saved these owls, and maybe yours too and will always be watching for this kind of activity during swarming season. I have nothing against bee’s in general but, the owls are my priority.

      Reply
    • Hilary

      Call a beekeeper to set up an beehive bait box nearby as an alternative. You are seeing scout bees who are investigating moving into your owl box.

      Reply
  3. Nate Snyder

    Recently had honeybees invade my Owl barn. The bees were removed and the barn has been cleaned. I also sprayed bleach on the inside of the barn to see if that will kill the pheromones left by the bees. If I line the inside of the box with sheet metal, will the bees be able to attach a new hive to this should They return?

    Reply
    • Hilary

      The smell will degrade over time and the bees will have no issues attaching to metal.

      Reply
  4. Michael Blott

    I confirmed a myth that Barn Owls will not use a box that has had bees. It may be residual comb wax or just the scent. One story was that an owl box owner flame charred the interior and was able to get owls to return. I can confirm that owls have not returned to my box after I removed a swarm with a small comb. I typically leave swarms alone and they take care of themselves but owl box hives can become permanent. I recently had an Owl box installer tell me he experimented for 5 years to create a spray to make the boxes attractive to owls after a bee invasion.

    Reply

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My name is Hilary Kearney. I’m the author of the book, “Queenspotting” and founder of the urban beekeeping business Girl Next Door Honey in San Diego, California. I’m an artist turned beekeeper on a mission to help new beekeepers succeed and educate the public about the magic of bees!

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