Last week two of the hives in our apiary swarmed.  The Lavender colony swarmed on Sunday afternoon, followed 24 hours later by the Salvia colony.  Both hives had been split this spring prior to the swarms, Lavender was split as recently as two weeks ago, but after inspecting the hives this weekend, it’s clear we should have split much more aggressively.

The Salvia colony produced a large swarm the day after Lavender swarmed (click any image to enlarge)

As both hives cast substantially large initial swarms we wanted to see what the situation was inside the hives post-swarm.  Robust colonies will frequently throw multiple swarms during a season if they remain crowded.

Three days after swarming, we watched as the Salvia colony moved 100 ft south to a different oak tree

To decrease the chances of losing more bees to swarms, we needed to see if we could determine why they swarmed in the first place.

Salvia Colony

On Saturday we inspected the Salvia colony hive. The Queen in this hive has always been a bee-making machine.  When we split this colony in February there was no shortage of bees, or brood.

We split the Salvia colony in February as they were building up quickly

What struck us looking into the hive after the swarm was there was no brood to speak of. None.  As the colony had swarmed on Monday, we knew there would be no eggs visible, but we didn’t expect to not see any larvae, or capped worker brood.  The only visible capped brood was drone brood, and not very much of that.  We expected that although the Queen would cut down drastically on egg-laying prior to swarming, we didn’t think she’d stop entirely.

There was plenty of pollen, and lots of uncapped fresh nectar, although very little capped honey, which was no doubt consumed by the bees just prior to swarming.

The only thing in abundance in the hive, other than bees, was this.

In spring it's important to check the bottom of the brood frames for empty Queen cups (yellow arrows), and capped Queen cells (Red arrows) that contain new Queen larvae

Numerous empty Queen cups, and at least a half dozen capped Queen cells.

Although we systematically went through the hive frame by frame, we did not locate a new Queen.  We did, however, see not one, but two Queens emerging from capped Queen cells.

Here the worker bees appeared to be removing the cap on this Queen cell, and we could see the Queen moving inside

With so many capped Queen cells we were concerned that this colony would soon cast an afterswarm.

We felt we should split out some of the capped Queen cells into our nucleus (nuc) hives to attempt to start new colonies from them.  However, the difficulty was the overt lack of capped brood to transfer in the split.

As worker bees are relatively short-lived, capped brood helps to provide insurance that there will be sufficient population within the colony to care for both the Queen, and any new eggs that a new Queen will produce.  A new Queen, however, will not begin laying eggs immediately.  She first needs to hatch, take her mating flight, return, and hopefully a few days thereafter begin laying eggs.  Then it takes time for those eggs to hatch.  If capped brood isn’t transferred, it’s a race to produce a new generation of bees before the existing population is lost through age, and attrition.

Without capped brood to transfer to the nuc (left), we weren't sure a split would work

However, as there was still a substantial population of worker bees inside the Salvia hive, we went ahead and split some of the Queen cells into two new nucs .  Some workers will fly out and likely return to the Salvia hive, others will be lost to age or predators in the field, and with no bees to replace them, we were careful to transfer generous numbers of worker bees into each new hive as well.

Although there was little to no capped honey, there was plenty of nectar and pollen, so each new nuc received frames of both. We were also careful to leave two intact Queen cells inside the parent Salvia hive.

There was no question the bees had recently been gathering a lot of pollen

It is possible for new virgin Queens to get caught up in swarms as the swarm exits the hive.  As we did not definitively sight a Queen during this inspection, we didn’t want to leave this colony completely Queenless, so we had to leave some Queen cells in the hive.  As there are no eggs in the hive, it is impossible for the bees to produce a new emergency Queen if we remove all the Queen cells.

In case the colony did not yet have a new Queen, we made certain to leave Queen cells in the hive

Overall, our impression is that Salvia simply ran out of room.  Between a large build up of brood, and a strong nectar flow, the hive simply became too crowded, as we obviously should have split this colony again.  This weekend we created two new nucs from Salvia, and managed to use up all the equipment we had on hand. So before we could inspect the Lavender colony, we first had to source some extra equipment.

Lavender Colony

On Sunday, after acquiring a new bottom board, and hive cover, we set out to check on Lavender.

Lavender was the first of our colonies to swarm

For the record, Sunday was the warmest day of the year so far, and wearing a bee suit, while standing in full sun in the apiary, we both almost melted into puddles.  The things we do for bees!

Strangely, if you knew nothing about the history of these two hives, at first look one would presume that Lavender was the stronger of the two swarm hives.  There was still capped honey in this hive, albeit not much, but there was also capped brood, quite a lot of it.  There were also NINE capped Queen cells, and a few empty Queen cups.

Workers tending one of Lavender's Queen cells

Our strategy with Lavender was a little different.  As this colony had some capped brood, and Salvia did not, rather than dividing the colony to create new hives, we opted instead to use this colony to balance resources within the apiary.  We did create one split, transferring Queen cells, pollen, nectar, brood and bees.  We also left enough of those same resources within Lavender to continue to sustain the colony.

We started this spring with just two surviving colonies. Just through splits, we're now up to 7 potential colonies in the apiary

We then divided the remaining capped brood between the two nucs we’d created from Salvia the day before, in the hopes that this brood will help provide a little extra insurance in the form of new population, while their respective new Queens get established.

For us, this is one of the major reasons for having more than one hive in an apiary.  It provides us with more management options.  If we didn’t have a hive with extra brood available, the Salvia nucs would be less likely to survive.

While transferring bees between nucs we did have to be mindful of the fact that after the swarm, when many of the worker bees have left, the swarm colonies have a disproportionate number of drones left behind.

Drones are produced by the Queen prior to swarming, and after many of the workers leave, the drones are very obvious in the hive

This was especially true of Lavender, who seemed to have upwards of 40% drones at the time of this inspection.  Interestingly though, the majority of the capped brood that remained was worker brood.

Drones though don’t perform any useful function within the hive, so we needed to ensure that of the bees we transferred, there were enough worker females to tend the brood until it hatches.

At the end of the weekend, with both swarm colonies inspected, we jumped from four, to SEVEN potential colonies in the apiary.  However, that said, not all of these colonies may survive.  We may have damaged Queen cells, there may be insufficient brood, the Queens may not return from their mating flights, or the two parent hives, Lavender and Salvia, may still swarm again, and leave those original colonies too short on population.  Between swarming, and splits, there is not a single Queen in our apiary that was here last spring.  Every single hive (hopefully) will have a new Queen this spring.

So now we cross our fingers, and hope for the best.  We’ll keep an eye on entrance activity over the next few weeks, and then reinspect each of the colonies for evidence of new laying Queens.

In the meantime, we’re hoping at least one of our swarms found a good home.

Hoping the bees can read, our neighbors, who have a hive vacancy, tried to encourage one of our swarms to move in

It really has been a remarkable ‘swarm week’, between the two swarms cast by our hives, and the three feral swarms we’ve seen pass overhead, not to mention the numerous other swarms all around the Bay Area [1,2,3], it’s been a beezy week!  With rain on the way, I expect things will quiet down for a while though, which gives me the perfect opportunity to get back to planting out the new garden.


[1] Locals encountering more bee swarms as spring warms up (KTVU). April 18, 2012

[2] Warm Weather Brings Swarm of Bees Early (ABC News). April 19, 2012

[3] The buzz: Honeybees are swarming, and that’s a good thing (Mercury News) April 19, 2012