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Why do Bees Swarm in Fall?

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What to do With Fall Bee Swarms?

Finding a Fall swarm of bees is not as uncommon as you might think. Though not the prime season for honey bees to swarm, it can still happen. Members of a Fall swarm face more perils than those from earlier in the year. Late season swarms have a reduced chance of surviving through Winter. So, what’s a beekeeper to do when we see a small swarm in a tree with leaves that are changing color?

picture of one of my small Fall bee swarms in tree

Swarms are exciting. As beekeepers, sometimes we love seeing them and other times…. not so much. Inf fact, despite the excitement of having bees to start a new hive- swarms can be a major pain.

The late Summer or Fall swarm is not a bonus that is likely to result in a healthy beehive – for that season and maybe never.

And, we often wonder if the effort to collect it is time well spent. But, most of us do it anyway – because we are beekeepers.

small swarm of bees in grass - what to do with late summer fall swarms

Bee Swarms in Late Summer Face Many Perils

There are several reasons that a late season bee swarm may not be a great opportunity. The major issues are related to the fast approaching time of cold weather.

Can the Bees Get Ready for Winter?

Winter is coming soon. As the days grow shorter and cooler, foragers will not be able to collect as much food.

Colony population begins to drop as the queen slows egg laying. But inside the hive, there is a lot of work to be done.

Winter food must be stored and in most cases – the bees must draw comb! Can the swarm build up enough to survive? In many cases, it will not.

Late Season Swarms-Risk to the Mother Colony

If the Fall swarm came out of one of your own hives, that hive too is now at risk. 

The colony that swarmed (the mother hive) must make a new queen from queen cells left behind and rebuild their colony population before Winter.  

Most beekeepers want Fall colonies to stay strong and get ready for winter. Raising new fat bees for Winter and storing honey is where we hope to see the bees expending energy.

However, the Fall hive will sometimes throw one or two small swarms. This leaves the beekeeper with a dilemma and the future of swarm and mother colony uncertain.

picture of a large late season bee swarm filling the air

Why do Colonies Swarm Late in the Season?

Well, do we really know why bees do anything?  Sure we see patterns and understand why bees react to certain stimuli. 

Hundreds of years of study have taught us much about some aspects of bee life. But, we still have so much to learn about honey bee behavior.

Bee researchers are not certain why colonies throw Fall swarms. These swarms are different from the reproductive swarms that happen early in the season – and often much smaller.

We do know that small late season swarms have an almost 0% chance of survival without beekeeper intervention.   Still, there is some merit in catching these small ones if possible.

Use the Extra Queen for Emergencies

Even if the beekeeper does not intend to overwinter the small swarm, there is still some value in catching it.

If a queen is present, the small colony can be placed in a nuc box for a while. The queen and even the bees with her may be needed in another colony-that is queenless and weak.

In this way, you can attempt to save the bees in the swarm, even if they don’t become a separate, stand alone hive.

image of free secrets of beekeeping book

My Fall Honey Bee Swarm Experience

It is late September, a couple of years ago. I see a small swarm in a tree.  I do not know if it has recently issued from a hive or has been up there for a week or so .  It is the size of a small cantaloupe at best !

As the Beekeeper, I am faced with a decision.   This swarm has almost no chance of building into a viable winter colony.

If I do nothing, the swarm will most likely die.  The beekeeper who tries to save these small swarms must be prepared to feed the bees heavily

And, it may still be necessary to combine smaller colonies together before cold arrives.

Using my Bucket to Catch the Swarm

The first thing- get the bees out of the tree.  Remember the mated queen may be worth the effort.  Even if she is not the greatest queen in the world, as long as she is mated, I could put her in a queen less hive.

Using my “bucket on a pole”  I reach up about  12 feet and bump the limb to knock many of the bees into the bucket. These bees are quickly dumped into a box containing 5 frames of drawn comb.

This is called a NUC box and is half the size of a regular 10 frame Langstroth hive.  It is a good idea to match the size of the box to the bee population.  A large box would be too much room for this small swarm to defend.

Do I have the queen ?  YES I DO.  A few minutes later, the queen is inside and some of the bees that I dumped in have come outside to inspect.

image of scenting swarm of bees at the front of a hive

Then, they begin to “scent” at the front signaling their sisters to come down. I am seeing more bees at the front door ! They are scenting to call down the rest of the bees still on the limb!

A temporary feeder jar with some sugar water is placed on top.  The small swarm does not have enough bees to fight off robbing attempts. I help them out.

Once most of the swarm is inside, the entrance is reduced to a tiny opening – approx 1 inch in width. 

catching small fall swarm in a nuc box

Hopefully the bees will realize this is the best chance available for them and stay in the box provided.  Once dark falls, I move the box to the bee yard. 

Ok, I can say I tried to save them. As I tell students in my online beekeeping class – you can’t save them all!  

Recap of Dealing with Fall Bee Swarms

Honey bee colonies that swarm during Spring buildup are called reproductive swarms. They have a better chance for survival. 

But when bees swarm in late Summer and into Fall, their survival is unlikely. These bees starting from scratch will not survive unless that are very lucky.

 We don’t know for sure why bee colonies do this risky behavior. Perhaps the colony is reducing the number of bees in their hive or just wanting to make a new queen?

Either way, it is surely a part of the big bee plan that we beekeepers can only marvel about.

Beekeeper Charlotte

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8 Comments

  1. Barry Hubbard says:

    Did the fall swarm survive? What did you end up doing? I just got a swarm on August 24th 2016, I’m hoping that it will make it.

  2. Hi Barry,
    No, it did not :(. There was a queen present and I did not see any robbing. However, when I checked again 2 weeks later, I saw only a few bees and no queen or brood. But as a beekeeper we have to try, right ? You may be ok if your swarm gets off to a great start. Keep them fed continuously until cold weather – if you have any dry pollen you might give some of that (be careful if you have Small Hive Beetles in your area.) Keep the entrance SMALL. Otherwise a larger colony will rob out your girls. Best of luck. let me know how it goes.

  3. Farley Redfield says:

    Chevrolet,
    I had my 3rd treatment of or the mites thursday. When I inspected wed I found my queen and her nurse bees all over on the lower frames. I was jyst watching yesterday and noted that some of the bees were carying out some white baby bees. I noticed too that some of these bees looked darker than what I’ve noticed. A few yellow jackets were around I managed to kill 4. Then all of a sudden I noticed the noise came up. I thought the bees were swarming there were so many coming out.

    The bee poop I noticed on the front, several single bees on the ground.

    I had not opened the hive on Thursday when I noticed this. The day before I did add on some gaskets around the tops of my boxes to seal off for winter. Thought maybe I gad got it too hot inside and no way for them to get out at the top.

    Anyway I looked again this pm friday and only a few bees, no queen, no honey, no brood.

    I was preparing to feed them and now none to feed.

  4. My brother built up about 35 hives over the last five years and some of it by ‘recovery’ for people with swarms in residences. This year, now as a matter of fact, this last week, he introduced a swarm that was taken in for the first time this late in the year. So far they have refused to remain in the ‘box’, swarm out and go to trees around the property.. from where they continued to attack the other hives- weaker ones, Lost 5 weak colonies so far!
    We captured them again and have them sealed into a hive to once again test them for accepting a domicile of their own.. feeding them providing frames already loaded with honey ect ect..
    This is the first time I’ve seen such repeated behavior of a swarm.. killing other colonies almost one a day.
    This will be the last attempt to ‘subjugate this swarm and will have to eliminate them if they ‘don’t go with the plan’.
    I’m wondering if there has been a change in the bees themselves these last few years, genetically, where this seems to be happening to other people more regularly in ‘adopting ‘late swarms. Anyway, this will be the last late year swarm we bother to recover for sure.

  5. Yes, I would not be surprised to have some genetic issues involved. I also wonder if weather has an effect. I have had several students in my online beekeeping class has this issue this year. Not with late swarms but mid season one. Giving them a frame with some brood – even a small amount-has been helpful for me in keeping bees in the box.

  6. Im fairly new keeper but still about 5 years in. had a large hive going into the fall,(i mean large hive). would have split the hive if had been able to do it in august but could fine no queens. Needless to say went into fall with about 70 pounds or better of winter honey, lots of brood and no indications of a problem. Around the end of october i checked my hives and no visible issues. Here it is December 24th, 50 degrees and I am checking my hives and the first thing I notice is that this particular hive has no bees moving around while the rest of the hives are out and active. So, you can guess what I’m doing next. I find a hive with the bottom board full of dead bees and all the honey still there. Wondering if anyone has experienced this and is it possible the hive swarmed with the queen. Also unlike in September, there wasn’t any brood? Can you give me some ideas so in the future I can prevent this? Seems as if there is a mistake to be made I’ve done more than my share.

  7. Tim, sorry to hear about the problem and I understand about making mistakes. Sometimes it is our fault and sometimes not. Sounds like you had good honey stores in late October. Assuming you had treated your bees for varroa mites (if needed), I wonder if the honey near the cluster was gone? It sounds crazy but if we have really cold weather for a prolonged time – sometimes the cluster will not move. I’ve had bees starve with a full box of honey in the next box above. Also, think about ventilation – we can wrap them bees up too tight and moisture inside the hive causes problems. Wet cold bees are dead bees.

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