Why Honey Bees Swarm in the Fall?
Yes, honey bees do swarm in Fall. While Spring is the main swarm season, a colony may cast a swarm in late summer or even September. Finding a swarm can be an exciting time for beekeepers but it is not always a welcomed sight. These late-season swarms face a race against time—with Winter approaching, both the swarm and the mother colony may struggle to prepare for cold weather. So, why does it happen?
Swarming is a natural process in which one strong honey bee colony divides to form another.
If you are new to this behavior, my guide to honey bee swarms explains how and why swarming happens.
Why Bees Sometimes Swarm Late in the Season
Do we really know why bees do anything? Well, sometimes—but they certainly keep us guessing.
Several conditions may contribute to late-season swarming, including overcrowding, a strong Fall nectar flow, queen issues and colony stress.
However, it isn’t always possible to determine exactly why a particular colony decides to swarm so late in the year (the bees’ productive year – not our calendar year).
Overcrowding and Late Nectar Flows
A strong late-season nectar flow (honey flow) can encourage colony growth at a time when we might expect the bees to be slowing down.
If the hive becomes crowded with bees, brood and incoming nectar, the colony may respond much as it would during Spring swarm season.
Weather plays a role too. In areas with long, mild Falls, colonies have more time to remain active than those living where cold weather arrives early.
Queen and Colony Conditions
Queen condition may also play a role. Colonies sometimes attempt to replace an aging or poorly performing queen (the bees can kill a poor queen -will they be able to make a new one).
Any queen-related changes within the hive can occur at the same time as late-season swarming behavior.
As with many things involving honey bees, what appears to be the obvious reason from outside the hive may not tell the whole story.
Pests and Colony Stress
Sometimes, what appears to be a Fall swarm may actually be a colony abandoning the hive. Heavy pest pressure, lack of food or other serious problems can cause honey bees to leave their home.
This behavior in bees is called absconding and is different from swarming.
In a true swarm, the colony divides to reproduce. During absconding, the entire colony leaves because conditions in the hive are no longer suitable.
If you find a nearly empty hive in Fall, don’t automatically assume your bees swarmed. Look for other clues that may help explain why the colony left. Perhaps the colony abandoned its home.
Why Late Swarms Face an Uphill Battle
A swarm that leaves the hive in Spring has months of warm weather ahead. A swarm that leaves in September may have only a few weeks to prepare for Winter.
This puts the departing swarm in a difficult position. It also creates challenges for the mother colony left behind.
Less Time to Prepare for Winter
Once a swarm finds a new home, the bees have a lot of work to do. They must build comb, establish a brood nest and gather enough food to survive the cold months ahead.
This is a tall order for a late-season swarm. Nectar may be available during a Fall flow – especially if you have a lot of fall flowers bees love in your area.
But, the amount and duration of nectar and pollen vary greatly from year to year. Cold weather can bring foraging opportunities to an abrupt end.
A small swarm faces an even greater challenge because it has fewer workers to build comb, gather food and care for brood.
The Mother Colony Has Risks Too
Don’t forget about the colony that cast the swarm. It has lost a large portion of its adult bee population at a time when strong numbers are important for Winter colony survival.
If the old queen left with the swarm, the remaining colony must also have a viable queen—or successfully produce and mate a new one.
Late in the season, that process can become more difficult as weather conditions change and drone populations decline.
For this reason, a Fall swarm can put both halves of the original colony in a difficult position as Winter approaches.
What Beekeepers Should Consider
Finding a swarm of bees is exciting at any time of year. But, when you find one late in the season, you have a few extra things to consider.
Can this swarm grow into a colony strong enough to survive Winter? The answer depends on the size of the swarm, your climate, available forage and how much time remains before cold weather arrives.
A large swarm with a good queen has a better chance than a tiny cluster of bees. Even so, most Fall swarms will need more attention than those caught in Spring.
A Little Help May Be Necessary
Do you have and are you willing to put in the extra work? If you have other hives – perhaps they can share a bit.
Providing drawn comb gives a late swarm an advantage because the bees don’t have to start completely from scratch. T
The queen has cells available for egg laying, and the colony can concentrate more of its efforts on raising brood and storing food.
Feeding may also be necessary when natural forage is limited. A Fall nectar flow can certainly help, but you can’t count on good weather or abundant forage lasting long enough for the colony to prepare for Winter.
Of course, location matters. A September swarm in a warmer climate may have considerably more time to get established than one caught farther north.
A Fall Swarm May Still Be Useful
A small Fall swarm may not have enough time to grow into a strong colony before Winter. But that doesn’t mean it has no value.
If the swarm has a good queen, she may be useful as an emergency replacement. The bees may also be combined with another colony that needs a population boost.
Still not sure a tiny cluster is worth the effort? See my guide on whether you should catch a small swarm.
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My September Bee Swarm
One September afternoon, I was surprised to find a small swarm of bees hanging from a tree near my bee yard. It was certainly not the time of year when I expected to see a swarm.
The cluster was small, but I decided to catch it anyway. At this point in the season, I knew the bees would have a lot of work to do and very little time to do it.
Using My Bucket to Catch the Swarm
Fortunately, the swarm was within reach. Using my trusty swarm-catching bucket, I collected the bees and set them in front of a small nuc box.
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.
Then, they begin to “scent” at the front signaling their sisters to come down. These bee pheromones are wonderful method of communication.
I am seeing more bees at the front door ! They are scenting by fanning their wings to call down the rest of the bees still on the limb!
Did My September Swarm Survive?
Unfortunately, no. When I checked the colony about two weeks later, only a few bees remained. There was no queen and no brood.
Sometimes, despite our best efforts, a late-season swarm simply doesn’t make it. This little colony was a good example of just how difficult it can be for a small swarm to become established so late in the year.
A temporary feeder jar with some sugar water is placed on top. Once most of the swarm is inside, the entrance is reduced to a tiny opening – approx 1 inch in width.
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!
The Late Season Swarm Unknowns
There are still many questions regarding bee behavior. Sure we see patterns and understand why bees react to certain stimuli.
We know that bees communicate with pheromones and adjust the daily workload to the needs of the colony. But, we still have so much to learn about honey bee behavior.
Bee researchers just don’t know why – but Fall swarms are different from the reproductive Spring prime swarms and often much smaller.
Final Thoughts
Honey bees can and do swarm in Fall, even though late-season swarms have less chance of survival. If you find a Fall swarm, consider its size, available forage and the amount of warm weather remaining.
Sometimes, with a little help and a bit of luck, these late arrivals have a chance. Even if it seems like risky behavior to us. If it came from one of your colonies – monitor that one as well to be sure they have a queen.
Harvested honey late this year from a strong hive, 2 years old. had 2 honey suppers with about 50 lbs of honey. 3 weeks later no bee’s in the hive. no dead bee’s in the bottom. Did I drive the out be the late harvest? Located in NE. Ct.
I would not think so if they still have plenty of food left inside the hive after you took your supers. There are many variables involved in absconding and sometimes we just don’t know why they leave. Were they healthy – mites under control and that sort of thing. I’m sorry to hear of your loss either way.
should I split a hive in mid Aug.? looks like they are building queen cells
That’s a difficult question to answer. Depending on your location, it could be difficult to get them ready for Winter. They could be replacing a queen – in which case it is often best to let them. For swarm control, I’ve found it nice to have a small nuc box on hand in case I need to temporarily created a nuc colony to give space and a place for the old queen to hang out until the colony gets over the swarm impulse. You can then try to overwinter the nuc or choose the best queen of the two and combine them before cold weather. https://carolinahoneybees.com/a-queen-bee/
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.
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.
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.
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.
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.
I’m so sorry to hear that. Ventilation is very important.
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.
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.