Swarm Trapping

What's on this page?

Trapping swarms is an age old method of increasing your apiary with wild bees. It’s an excellent method for acquiring good genetics of feral bees, and for profiting from your neighbor’s healthy bees.  You're not actually trapping anything, just enticing it to occupy the box you've provided.  Swarms come almost invariably from healthy hives.  Swarms should not be avoided, nor swarmed queens be re-queened unless found objectively to be unacceptable.  Despite what you may have heard, swarms almost always come from healthy hives of reproductive capability.  Swarms are a good thing.  They are the result of the hive’s reproductive urge.  It should never be stifled or frustrated, though it can be profitable to redirect the urge.

I find trapping swarms to be way more convenient and fun than responding to swarm calls.  With swarm calls you need to be on your toes all the time, need to have your kit in your car if you're at work, need to work at a place that is permissive with you leaving with no notice all the time, and you have to go deal with people, which depending on your personality may not be your thing.  Traps allow you to do your swarm collecting on your own time.  There's no nail biting, no missed calls, and I don't know about you, but I'm a pretty busy guy with a very wild and changing schedule.  None of this is to say that you shouldn't answer swarm calls if that's what you like to do and are set up for.  Catching swarms is a lot of fun.  You do you.

I recommend against buying bees.  The loss rates on first year packages are horrendous.  What other product would you buy with zero return policy that has a 50% chance of failing within a year?  On the other hand, for the price you'll be spending on a single package of bees, you can put together up to three swarm traps that will give you free bees for decades.  And even better, you'll still be able to use that equipment later on in the year if you don't catch a swarm.  Dead package bees are of no use to anybody.

"I can't catch swarms in my area because I'm surrounded by commercial/package bees and all the swarms will be commercial treated bees." 
I hear this one a lot so let's talk through it.  The first and most important point is that it doesn't matter because no matter the source, the bees are still free.  They still build comb like crazy, they still build up, they still can make honey, they still pollinate, and just like everything will one day, they die.  However, I'd be willing to bet that they will have better survival than packages which have none of the benefits of swarms even if they come from the exact same source.  Swarms are overwintered queens.  We already know that much about them.  They were good enough to survive the last season, overwinter successfully, and are healthy enough to build up and swarm this spring.  Treated or not, these bees are nothing at which to turn your nose up.  Even if they do die, they'll help you to change your outlook on beekeeping.  You'll leave the mindset of fear of loss, because now you are not protecting your investment of bees.  You got them for free, and you know where to get them for free again.  You have no idea how freeing that is in your beekeeping experience, until you've experienced it.

I always love a good analogy.  So let's say swarm trapping is like fishing.  When fishing, there are a bunch of differet factors which adjust your chances of catching a fish.  You can have the best rod, the best reel, the best bait, the best line and the best waders, and if you're fishing in a hole with no fish, your chances of catching a fish are pretty slim.  Likewise, the hole could have plenty of fish but if you're using the wrong bait, they might not be interested at all and you won't catch anything.  But the more of the right factors you can get together, the greater the chance you'll catch fish.

Likewise with swarm traps, you start with zero and by incorporating the aspects of swarm trapping you see below, you'll find a greater and greater proportion of traps will catch swarms every year.  You start with a box and you gain factors from there.  As with everything, there is experience involved and you'll learn ways to make things work better as time goes on.  Expert swarm trappers will on average fill all their traps, and some more than once, every year.  A new beekeeper (who often makes the mistake of assembling far too few traps) may not catch any.  Pay close attention to these factors, so you're being the most efficient with your time and resources.

Box volume
One of the more important factors in swarm traps is the box volume.  Studies show the optimum volume for a swarm trap is between 35 and 60 liters (9 to 15 gallons or 1.5–2 cubic feet).

Common trap successful trap configurations using standard Langstroth equipment are therefore the following:

8-frame deep boxes are 1.25 cf, 9.4 gal, or 35 liters, falling right at the bottom of our range.  They are compact, a single unit, and of the right size.  If you use 8-frame deeps, this is going to be one of the best options.

10-frame deeps are 43 liters which means those of you in the majority who use 10-frame deeps for brood chambers are in luck.  These are most of my swarm traps.

5-frame nuc: 23 liters, which would preferentially catch Africanized swarms due to their smaller size, or you can double up to make 46 liters. Double box traps are slightly more complex, using more equipment.  Double 5-frames hang closer to the tree while offering the same size as a single deep.

8-frame medium, 24 liters but again, we can double up to 48 liters.  Since 8-frame mediums are becoming a much more common hive configuration, this one will be good for those of you that use 8-frame mediums.

A ten-frame medium, 29 liters, double up to 58 liters.  This style is for those of you that use 10-frame mediums.  They are larger and heavier and more complex due to being two boxes.  I use these. They are slightly more unwieldy than 10-frame deeps.

Custom made hive types I leave to your judgment.  But the most successful traps will be of volumes between 35 and 60 liters.

Used box
The state of the box is an important factor, which is why it is so high on this list.  Fresh boxes are often still offgassing fresh wood scents which can be too powerful for bees to be attracted to.  However, a nice used box with the smell of bees in it is very popular and one of the best indicators of a good swarm trap.  Unfortunately, not everybody has access to used boxes especially starting out.  So you can buy used boxes, which are often cheaper than new, or you can simulate a used box by rubbing propolis inside the box, if you have any around.

Used comb
A frame of old dark or black brood comb is also high on this list.  Not only will the swarm get the smell of a hive, but also the queen will be able to begin laying as soon as she is able, without having to wait for comb to be built.  If you're aiming for small cell, this will also give your swarm the first generation of workers raised on small cell comb, giving you a head start on that front.

Repeat location
When you have found a spot that caught a swarm, keep using that spot, especially if you like the bees that you caught.  For some reason we do not yet understand, swarms will often be caught at the same spot year after year after year, even on the same branch in the same tree.  Which reminds me, I see so many beekeepers cut branches from trees when retrieving swarms.  Don’t cut the branch.

If you're using a frame type hive, like the Langstroth or Layens, you'll want to follow a few pieces of advice.  Number one in my experience is don't use plastic frames.  I have never caught a swarm in a swarm trap with plastic frames.  Bees just don't like them.  I find foundation is excellent for swarm traps because I don't have to worry about getting the trap perfectly level, even if I may not use foundation in other circumstances.  However, other expert trappers I know use foundationless with no issues at all, having developed a mounting method that includes shims to level the box.

Entrance size
The optimal entrance size is two square inches.  Many of my swarm traps use a broken corner as an entrance, but quite a few use a 1.5" round hole drilled with a hole saw.  If you do the math, a 1.58” inch diameter round hole is exactly two square inches, so it works just fine, plus it fits with the disc entrances you see in the picture below which are on those ones with round holes so they can be easily closed when needing to be moved.  I use some window screen stapled over other entrances for the same purpose.  The hole doesn't have to be round.  An appropriate sized slot will work just as well. 

Configure yours like the lower one.  The upper one could rotate on its own and trap the swarm inside, killing it.  It has happened, though not to me fortunately.  These are five frame plywood nucs and not the best for swarm trapping except for small or africanized swarms.
5-Frame Nucs

The Lure
Bees use a location smell called Nasonov Pheromone.  You can see this when you place bees into a new hive, they will stick their abdomens up in the air and open a gland between the last and second to last segment and fan with their wings.  That's the Nasonov gland.  Swarm lures have been developed to mimic this pheromone.

Swarm lures are available from most beekeeping supply places and consist of a little plastic vial of yellow fluid that smells like Lemon Pledge.  These often cost in the range of $2.50 each or more.  However, I have a cheaper option that seems to be just as effective if not more.  Part of the Nasonov pheromone is a chemical called citrol.  Perhaps you can tell by the name why it smells like lemon.  A cheap substitute is lemongrass essential oil which for a small bottle costing less than $10 can make many dozens of swarm lures.  Turns out, lemongrass oil is about 60% citrol.

The lure is made by placing a sheet of paper towel in a ziplock sandwich bag.  I use the shorter sheets because folded in half, they fit perfectly.  Then just drip ten drops or so of LGO in the bag on the paper towel and seal it.  Don't worry, the oil will permeate through the plastic and slow release.  If you drip the oil on the paper towel without the bag, or just directly into the hive, it will evaporate too quickly, running the bees off initially, and not drawing them at all later on when it is gone.  If you don't get the bag out of the hive soon enough after retrieving the swarm, bees may chew holes in it.  And wax moths will definitely chew holes in it.

Box height
Having the trap about the right height from the ground is somewhat important but not as important as other aspects.  8-15 ft is the accepted optimum, however, you can catch swarms at just about any height bees will find the box.  I imagine 400 feet in the air probably won't do the job very well because I doubt there are many bees up there.  Of course it's hard to put a box up past a certain height.  Jason Bruns, a swarm trapping expert friend of mine, puts his only about chest high, I believe, or on the ground.  In the 2017 season, I caught several on my deck, sitting about 8 feet off the ground, one sitting on my front step, right at ground level and a number about six feet in trees.  The way I generally do it for trees is to lean my 6 foot ladder (which fits in my Toyota Corolla bee truck) against the tree, sit the box on top, and screw it into the tree with Torx drive screws.  Don't use cross head or Phillips, they don't have the driving power and you don't want to push yourself off the top of the ladder with a box of bees.

Bees use landmarks to find their way around sometimes like we do.  They follow fence rows and use large trees as landmarks.  By looking for large trees in geographically prominent places, you can put the box in the path of more scout bees and give yourself a better chance of catching a swarm.  Look for areas between spots of habitat and no habitat, on the edge of forested areas, in prominent trees near open areas.  If you're trying to catch swarms from your own hives, try spots more than a hundred yards from your hives.  Swarm traps are also useful in your own apiary but may or may not catch your own bees.

Empty space in box
Bees seem to like some empty space in the box.  I have found that boxes full of comb really don't work well.  Not only do the bees not occupy the traps optimally, but wax moths make a huge mess of the thing, destroying your nice bait comb.  Better to put it on other hives or store it in a way that keeps wax moths at bay.  I store my empty swarm traps (and other comb) on their side on my deck, open to the light and air.  Foundation works well because there is still 1 3/8" of space between the foundations, giving plenty of open space for the scouts to crawl or fly around inspecting the prospective hive.

In a trap, you don't want light from above.  Bees are okay with some light, but using something like a white plastic bucket will be much less desirable because the light will permeate all parts of the cavity. 

Sun Exposure
Excessive heat will cause a colony to abandon a swarm trap.  Place traps in spots that will have dappled shade or midday shade.  Swarms may start work in a box, but they're not committed to it for several days.  If in the first couple days they find something they don't like about it, they will leave again.

Free of Pests
Pests like wasps, mice, birds or anything else will prevent bees from moving into a swarm trap nearly 100% of the time.  They will not participate in hostile takeovers.  They cannot afford battles.

Weather proof
The box needs to be reasonably weatherproof.  If the box is not dry, bees will likely not move into it.  This can be assured by building the bottoms so they can drain water and the tops so they can shed water.  Also, it is advisable to have decent weatherproof boxes so that if you forget them and they sit out for a long time, they will not be damaged.

Store Prepared Traps Outside
Once you've prepared all your traps, hopefully before swarm season, a handy tip is to store them outside before they are placed at trapping locations.  The smell of this large number of available cavities will attract many bees and for a number of years, I have found that my home (wherever that happens to be at the time) is always the best spot to catch swarms, by sheer numbers.

For your convenience:
You want a lightweight box.  Even a double ten frame medium is getting a bit large, and I know because I've pushed many of them up ladders and screwed them to trees.  I've also had my share of falling down experiences trying to get heavy boxes full of big swarms down out of those trees.  It's a particularly unfun situation, and remember, we want treatment-free beekeeping to be fun.  Find something that works well for  you and use it.  One thing I've seen lately is boxes made out of plywood that are five frame nucs with open space in the bottom.  This makes them easier to handle, I assume.  But I wouldn't recommend building your own when there are so many good used boxes around and ones of standard size so you can use them later.

You also want something that's easy to attach to a tree.  Jason Bruns uses lightweight chain and cheap ratchet straps, which avoids the screws in the tree like I use.  It also allows him to level the box as he uses foundationless frames.  While I do not believe the screws are hurting the tree (I don't leave them in and the tree heals pretty easily) some tree owners may not appreciate it.

Also, watch out for squirrels.  Sometimes they will decide they just really have to find out what is in that box.  Squirrels are jerks.

Summary (Recipe)
Follow this best recipe for the best swarm trap that will bring you free bees for the rest of your beekeeping life.
  • Used 10-frame deep
  • One old brood comb frame, nine wax foundation frames
  • Lure
  • 8 feet up in a prominent tree near an open area
  • In a spot where swarms have been spotted before
  • 1.5" diameter round entrance
  • On the north or eastern side of the tree
Of course, you can make adjustments as needed, with all the items listed and explained above.  You don't need all of them to catch swarms, you will learn what works and what doesn't in your area, as you go.

Video of my Swarm Trapping Talk on YouTube