Perhaps you’ve been told “Just wait a couple of days, and maybe the bees will move on.”
Let’s break that down into the realities of honey bee behavior. It’s important to understand whether newly-observed bee activity means the bees are now permanently resident there, or you are just witnessing a momentary phenomenon.
Bees active at a cavity (versus bees gathering in an exposed location, such as a tree branch)
Notwithstanding what Winne the Pooh would tell us, honey bees overwhelmingly prefer to live inside an enclosed cavity. Common places are inside a hollow wall, underneath the floor of a storage shed, or inside a hollow tree. They need protection from wind, precipitation and predators. They also need to carefully control the temperature and humidity for the sake of rearing their young. (Bee brood, the larvae stage of their development, are very sensitive to fluctuations in temperature, humidity and nutrition. At some stages of development, the nurse bees look in on the growing babies at least once every 4 and a half minutes!) Whenever you see bees coming and going from a cavity, there’s a high likelihood that the traffic means they bees have colonized the place. More information on how to tell if the bees are there to stay can be learned from the YouTube video 5 Ways to Tell if Bees Have Moved in.
But bees that are clustered in an exposed location–a place where there is no cavity to hide inside of–almost always are camped out temporarily, with the intention of moving their entire population into a cavity. Sometimes they can’t move on, such as when their queen is unable to fly reliably. In such cases, they build honeycomb right out in the open. So if you see the edges of the honeycombs built in plain sight, it’s safe to say that the bees are there to stay. But this is a one-in-a-thousand occurrence. So when a cluster of bees is observed “in the open” like the branch of a tree, the questions that still needs to be answered are “will they move on by themselves?” and “will they move somewhere on my property as their permanent home?”
Will bees, clustered on a tree branch (or other exposed location) move on? It depends on various factors. Do they WANT to move on? Yes, 100% yes. They want to move to a secluded cavity. Evidence from thousands of bee swarms have indicated that the probability of moving depends on two main factors: 1. Can they find a place to move to; and 2. Can their queen make the flight? If the swarm cluster is close to the ground (within a foot or two) or is located low on the side of a fence or other exposed structure, chances are, they made an emergency stopover and cannot continue their intended travel as a swarming cloud of bees. So, as a general rule, bees clustered high in a tree will move on, while bees clustered near the ground will probably be marooned there, long term–with a high likelihood that they will build a hive “in the open.” Seasonal weather also plays a factor. When bees split their hive in late autumn or winter, there is a much greater incidence of becoming stranded in an exposed location. We have found that–in the Sonoran Desert–swarm clusters observed in November through January are far more inclined to stay in their exposed “campsite” than bees that cluster in exposed locations in springtime. More detail on the three phases of bee clustering is found on our “Understanding Honey Bees. Separating Fact from Fiction” page.