The maples are about to bloom, which means it's that time of year again. Our local honey bees have survived another winter, and they know that spring is in the air. It's time to reproduce!
Honey bee colonies are a super organism. No single bee can survive without all of the others. So, when it's time to reproduce, the colony has to divide itself. One colony becomes two. And since two colonies can't live in the same hive, one of those two new colonies has to find a new home. We call this a swarm.
Before we go any further, I want to let you know that swarms are a very safe time to be around honey bees. Yes, it's a lot of bees, but they're just looking for a home. They have nothing to defend, so they have no reason to sting. Also, the bees gorge themselves on honey right before leaving the hive, so it is physiologically difficult for them to sting. That doesn't mean that you should mess with a swarm, of course! Just don't be too scared. The bees have no interest in you, and it's a really cool thing to be able to see.
When a hive swarms, half of the bees leave with the original queen to go find a new place to live. The departure is pretty impressive. First, the hive looks like this:
Then the bees fly off in a massive cloud (swarm). They go find somewhere safe to hang out for a while:
While there, the bees send out scouts to find their new home. What are the scouts looking for? A relatively large, dry cavity. In nature this is often a hollow tree. In warmer climates, sometimes the roof of a small cave. In the city, it can also be the walls of a building, if there is a hole that lets the bees into it. Once all of the scouts have agreed on a final home, the swarm lifts off again, flies to the new location, and starts to build a new hive. It looks pretty cool too:
Of course, we prefer for our city bees to build their homes in places where they are convenient to people. That pretty much always means a managed hive. Managed hives are also much less likely to swarm than feral ones, since there are lots of things that beekeepers can do to prevent their hives from swarming.
Thankfully, when swarms happen, they are easy to catch and transfer to a hive, as long as they are accessible (e.g. if they're 40 feet up in a tree, they're not accessible). If you have a swarm in your yard, call a beekeeper to come take care of it. Peter can be reached at 206-519-8505. If he isn't available, the Puget Sound Beekeepers Association maintains a list of beekeepers able to come remove swarms, which can be found here.