honey bee behavior robbing

Robbing and fighting and falling in clumps

Last week, Scott Mathews, who lives in drought-besieged southern California, came home to a hive in turmoil. He writes:

I came home today . . . to discover a lot of bees in the air and what looks like combative bearding. [There are] clumps of bees falling from the top entrance and what looks like new piles of dead bees on the ground and a few dead on top of the hive. I only saw one battle occurring on the ground though.

Being new at beekeeping, Scott didn’t know if he was seeing a colony being taken over by another (usurpation), a swarm, or some other kind of attack. The next day, he continued his story with photos:

I have attached a few photos of my hive from this morning (the second day of the attack). . . . There was much more activity the evening before.

Initially there was a clump of bees about 6 inches wide and about 8 inches tall with clumps of bees falling off and re-coalescing at the top entrance. There were also small “battles” occurring on the ground which looked rather one-sided (6 to 1).

After sunset I went back to the hive and noticed that the main entrance (which is JUST over 3/8th inch high) was PACKED with dead bees. So the only open access to the hive is the top entrance which is an opening about 20% of the hive width and just over 3/8th inches high. The photos are the morning after I first noticed the situation and the attack seems to be continuing.

The hive is inside a fenced off area with 6-foot high fencing and is about 12 feet by 8 feet. The 4th side is a block wall. I have gates at both ends. The photos are taken about 7:30 A.M. in sunny Southern California.

In my opinion, this is a classic case of robbing honey bees. Robbers follow their sense of smell to locate sources of food. Air that is leaving the hive is laden with odors, including the aroma of honey. The robber bees congregate in areas where they detect the smell and repeatedly try to get in. Entrances, ventilation ports, space between boxes, cracks in the wood, and poorly fitting joints are all places where the scent can leak out.

Robbing gets worse in times of drought. Honey bees suddenly have a lot of time on their hands with nothing to do, so they are perfectly willing to steal nectar from another hive. The hive being raided tries to defend itself and fighting ensures. Dead bees are commonplace.

Because robbers can do a lot of damage in a short time, and because it can be difficult to stop once it starts, prevention is key. In my own apiary, I’ve had good success with reducing the entrances at the first sign of dearth (especially on smaller hives) and leaving them reduced until the autumn rains begin. Other beekeepers avoid opening hives as much as possible.

An invention called the “robbing screen” also works well. The robbing screen fits over the front of the hive and creates a new entrance that is not in line with the actual entrance. The hive scent drifts out of the conventional entrance and attracts the robbers while the bees living in the hive soon learn the location of the new entrance. Some robbing screens also have a metal plate around the new entrance to further reduce odors from that area of the hive. Any robbers that manage to find the new entrance can be handled by the colony because the number is small compared to the large mobs at the fragrant entrances.

Scott kindly labeled his images, so if you are not accustomed to robbing bees, the photos are quite instructive.

Thanks, Scott, for the share.



Wherever the scent leaks out, the robbers congregate. © Scott Mathews.


Hoards of dead bees on the ground. © Scott Mathews.


The bottom entrance is so full of bodies, not even the residents can use it. © Scott Mathews.


  • I also live in Southern CA and the robbing has been especially bad this year. I have successful stopped robbing in progress by stuffing pine needles in the entrance. It keeps robbers out and house bees come down to clear it away so, that brings more bees down to defend the entrance. Also, the bees will clear as much or as little as they want to over the next few days, allowing them to decide how big of an entrance they can defend. When I got word from other beekeepers of robbing being particularly bad, I stuffed all the small hive entrances with pine needles so they could pick their own entrance size. If the point of cracking of stacking the hive boxes unevenly in those pictures was to vent some heat or to provide an extra entrance, I have found that drilling a 1″-.5″ hole in an upper supper works just as well and is much easier for the bees to defend.

  • My bees almost got robbed a couple of weeks ago too. Every morning around 6:30 a.m. I look out at my hive and see if there is any activity. Sort of like having my caffeine in the morning. Around 8:30 a.m. that same morning I just happen to glance at it and there were lots of bees heading for my hive. I can only compare it to the flying monkeys from the Wizard of Oz. Fortunately my husband and I were able to stop it. We threw a tarp and then closed the entrance with a piece of wood which was covered with Vicks Vapor Rub. Left the hive closed over night and built a robber screen the next morning. The girls were not happy! We went into the hive two weeks later and all seemed to be back to normal. Fortunately the day this happened it was cool, cloudy with a chance of rain so I needn’t worry about them over heating.

  • Hello Rusty…. I love your blog, and learning something from every posting. Thanks for all your efforts. I second your idea of robbing in Scott’s beeyard. It’s common in a dearth, which many areas of Southern California are in right now. My three backyard hives are in residential Long Beach, with lots of watered gardens, trees, etc., so we’ve got stuff in bloom now. More rural areas are harder hit. If I suspect robbing or any other upset, I drape a wet sheet over the hive Again, thanks for your great work!

  • Can you buy ‘liquid smoke’ in the US (used instead of a smoker)? Sprayed on the bees, I have read it deters robbing (but I have not tried it). Placing a sheet of glass or a board in front of the entrance would have the same effect as a ‘robbing screen’. If the robbers are dusted with flour, it might be possible to find where the robbers are coming from. If possible, the robbing hive should be removed – failing that, the robbed hive should be moved. In the autumn, in the UK, entrances are reduced and hives are not inspected – any cracks etc. should be sealed. Apart from robbing, wasps (‘yellow jackets’) can be a problem – I have lost a strong colony this year from a wasp attack, despite reduced entrance.

    • Brian,
      A sheet of glass will not work as a robbing screen because the scent of the hive cannot pass through it. The robbing screen works because the robber’s ability to follow scent trails leads them into the screen. Whereas, the native bees, emerging from their hive, encounter a screen, climb up, and re-adjust to a new entrance. They return to their hive by virtue of a visual memory.

      More on this at http://www.beehacker.com/wp/?p=1030.

      • Tom Rearick says that placing a sheet of glass in front of a robbed hive will not work. I have never had to try this but it is the standard advice in the UK.

          • If robbing starts reduce the entrance to one bee space using an entrance block and/or grass. This enables guard bees to protect the colony more efficiently. Placing a sheet of glass in front of the hive entrance so that bees have to go around the sides for access can also help.
            National Bee Unit
            Food and Environment Research Agency
            Sand Hutton, York. YO41 1LZ
            Telephone 01 904 462 510 e mail nbu@fera.gsi.gov.uk NBU Web site: http://www.nationalbeeunit.com
            May 2011
            ©Crown copyright. This sheet, excluding the logo, may be reproduced free of charge providing that it is reproduced accurately and not used in a misleading way. The material must be acknowledged.

  • I am also in dry southern CA. This is my first hive, lots of brood and active bees but they have not stored much honey. I have been told to feed them but have not found an easy safe method and am worried about causing robbing.
    How do I build this mesh safety net?

    Thanks Rusty, I love your site!

  • Rusty,
    Thanks to your wisdom (and your blog) I have learned loads about keeping my bees.

    After several days I am certain you are correct about the robbing situation. I stuffed the upper opening to reduce access to raiders. 2 days ago I had NO bees flying. Not a single one. Yesterday I had about a dozen or so at the upper entrance and noticed that the lower entrance has been almost cleared of bee corpses. I’m going to wait a bit longer before I open the hive for inspection. I need to determine hive strength, stores and other conditions.

    I will definitely be building a moving screen similar to the one you linked.

    I’m glad that I experienced this situation (even though it was freaky scary) AND that I could share it with you and your other readers.

  • Well, That’s that!

    The colony was totally devastated. I opened the hive to find stacks and stacks and stacks of corpses. No honey left. Collapsed combs (partially melted). Gnawed wax everywhere. A few wax moths have already moved in but no hive beetles. Loads of dead capped brood. A few stragglers hanging around but not enough to consider it a colony. Probably less than 200. It was too dark for me to see if the queen survived. But that doesn’t matter.

    I’m gonna chalk this one up to experience and drought.

    It’s not a total loss. I harvested about 3 1/2 gallons of honey 2 months ago. (I doubt that weakened them as they had 1 1/2 mediums of honey remaining).

    When I get a job I can buy a new package and take better care of them next time, with my new moving/robbing screen installed when they move in.

    I may be down, but I’m not out!

    • Scott,

      I’m glad to see you are maintaining a positive attitude. I too had to learn the hard way; those are lessons we always remember.

    • Ah gee Scott, that sounds heartbreaking. Guessing you don’t have 2 hives to try to manage this? Wonder if there’s a beekeeping association in your area. Maybe you could at least get your remaining supers nicely cleaned up on top of a healthy colony, so you can store them, and have good comb ready to go for your next round. Really sorry to hear the story, I’m going to work on both my hives tomorrow and get robbing ready as best as I can.

      Kelton (Aussie transplant to So-Cal)

  • I finally got bees this spring for the first time. They were going great and upon the previous check (late July) they had filled the hive body with comb and a super full of honey. We added another empty super and swapped a few of the empty frames and full frames around. Today we cracked open the box to discover no new comb, and the relocated honey gone. We removed the newest super to look into the first one (which was supposed to feed them this winter) and were horrified to discover all of the honey gone out of that one as well. Upon looking into the hive body, we discovered most of the frames were empty, uncapped comb. In total there was maybe 6-8 oz of honey left in the hive. There were no dead bees, no shredded comb and the bottom board was clean of almost all debris.

    And to top it off, it does not appear that we have lost any bees at all—the hive body was packed with bees, there was a small cloud flying around us and a good amount milling around in the empty super. I haven’t noticed any fighting, save one time this past May; I heard a buzzing noise even though I was in the house. I went outside and there was a cloud of bees, perhaps 25 yards wide. They were darting back and forth and sounded angry. About 15 minutes later it subsided and there was a beard of bees hanging out on the porch, waiting to get back in-it had appeared that my hive won the battle. I’ve tried to find an article on missing honey (but not from robbing) but have had no avail. Any answers?

    • Well, Shanna, there are so many things I don’t know that I can only guess. I would like to know where you are (what state or province) and also whether there is any brood in the brood box, and whether you have a queen.

      However, my guess goes like this: Your bees had a good spring and everything was fine until the summer nectar dearth hit. Then your bees could find nothing to forage on, so they began eating their stored food. Now, going into fall, they have virtually nothing to take them through the winter.

      It may seem like they ate it really fast, but your summer colony is much, much bigger than a winter colony and it is also more active, so it can tear through a lot of honey in a hurry. That same amount would have lasted much longer in a winter colony.

      If you have a queen and she is laying at least a little, the colony can remain viable as long as it is fed. If you don’t have honey saved from that hive, you will have to feed syrup, candy boards, or something similar to get them through the winter. In the spring, you will have to feed pollen as well, if they don’t have any left.

      It is an unfortunate situation, but fairly common, especially in years with long, hot summers and little rainfall.

  • Hi Rusty,

    I am perplexed by my bees behavior. I’m assuming it is robbing or attempted robbing I’m seeing, as it sounds much like this post.

    On my strongest overwintered hive. I see clumping/balling little mounds occurring near the reduced entrance….sometimes the mound falls/rolls off and flies, sometimes it just melts away and there seems to be no injured or dead bee. I usually can’t tell which bee is the center of it all. There is no increase in dead bees on the ground, or bottom screen, and I don’t see rolling one on one fights.

    I was able to figure out which bee was the center a couple times…the mounding bees seem to be licking and touching tongues with this center bee, with others of the mound pushing in aggressively to do the same.
    Do you think they are biting? They don’t seem to be going after wings or abdomen….but its really hard to make sense of the ball.

    I wondered, with the dearth right now while we wait for blackberries up here in the foothills…..are they just hungry and transferring any nectar before the poor worker gets inside?? They have a full super of capped honey from earlier this spring.

    I put on a robber screen anyway. I hope I described this well enough for you to envision it.

    My spilt from this hive WAS being robbed. So there are bees around looking for sure.


    • Carol,

      It’s hard to tell without seeing it. But if a dearth is on, it could be the guard bees are carefully checking all those who attempt entry or, as you guessed, they could be offloading the nectar right at the entrance, especially if the nurse bees are waiting for it. If it was actual robbing, you usually see some pretty aggressive behavior, dead bees, and tumbling fights. Robbing screens never hurt. I sometimes leave mine on all year.

  • Hi Rusty, I love your site and have learned so much from you in this my first year (I took a class last year but this is my first year on my own). I’m wondering if you could help me out with a question. The background: Yesterday evening I had a robbing situation I was NOT expecting…I extracted my first super of honey, beautifully made, by my strongest hive (I have three hives in bee yard, a local extension class has three more) yesterday. After spinning the frames bone dry, I waited until late afternoon, drove over to the bee yard with the super in a covered tote, and returned it to the hive. From covered in tote to covered in hive was less than a minute. Almost immediately, bees from another hive came pouring out, heading for mine. Tons of noise, fighting, killing. I ran to my car, got a robber screen and slapped it on. Waited for the activity to stop (all three entrances on screen were shut) but the robbers kept at it, covering screen and picking off returning foragers. I was heartbroken. This is the most docile, productive hive and, I will admit, my favorite. As I watched the robbers attacking the forages, I noticed an uptick in activity outside my other big hive, which is about three feet away. I put a robber screen on it with only smallest entrance open. My third hive is 12′ away, on its own, and is the smallest, so to be safe I changed entrance reducer to smallest hole. I had to leave as it was getting dark but came back early this morning. Activity at my other two hives is totally normal, but I have several hundred bees trying to get into the robbed hive. Some fighting still, though not as much as last night. About half of the bees are carrying pollen…I believe they are foragers still trying to return to the hive from yesterday. But there are other bees investigating all over the outside of the hive and all over the underneath of the screened bottom; I assume they are robbers. The hive is still completely closed up. How long do you think I should leave it closed? I want to open up the smallest, single bee entrance for the poor foragers but don’t know if I should do that, or at what time of day. Any ideas welcome! Thank you again for a great site <3

  • Rusty, I’ve read through all your excellent robbing topics and many other sites as well. I still can’t tell exactly what’s going on and it’s driving me nuts. I’m hyper-vigilant because I lost 2 colonies to robbing.

    Last week, I collected a late swarm. They need comb, because they scornfully chewed down the comb with pollen I supplied them. So I’m feeding 1:1 (no additives) from a quart jar with perforated cap, inside an empty super.

    Since masses of Liriope flowers popped open today, and the bees are all over them, I thought it was a good time to swap out the feeder at 85*F instead of doing it just before dusk. Whoops. There was a huge onrush of bees. But, why did they know where the secret door is? Had the robbers already figured it out? I saw no fighting, however, most dead bees here are instantly snapped up by a fat salamander who lives under the floorboards.

    I couldn’t tell if the bees were taking off heavy, so I closed the 1- bee gate. Better safe than sorry, I thought. But then…one bee did a waggle dance on the outside of the robbing screen. What? Why tell trapped robbers of a food source? With a crowd on both sides of the screen, it’s possible that interior robbers are feeding outside robbers, or else foragers feeding back to inside bees. My other, 5-times-larger colonies do not have this much activity! Do I have a correct diagnosis, or am I being paranoid and overprotective?

  • Hi Rusty,

    Follow up on yesterday: When I opened the robbing screen gate at dusk, a few dozen bees flew out and headed west. So there were some robbers. The bees clustered on the screen moved in while a house bee fanned, and a few dozen bees flew in from all directions. Five minutes later when then they were all obediently corralled, I left the top gate open just big enough for a squeeze-in.
    Checking a few times this morning, it appeared to be normal traffic. Perhaps because of being trapped, the trapped robbers didn’t signal it was a favorable source. Likely the situation was helped after rain at night and the Liriope is humming with action. Perhaps what I saw yesterday the onset of robbing, but didn’t escalate to the usual full-blown signs.
    Thanks for listening! 🙂

Leave a Comment

This site uses Akismet to reduce spam. Learn how your comment data is processed.