Bumble bees

We have some bumble bees nesting in our balcony wall. I was leaning on the balcony ledge this evening when I noticed a worker bee carrying pollen disappear into a hole just below the ledge. Another one followed a few minutes later and a drone bee also emerged. My first thought was panic – we have bees, what if they swarm, will I have hundreds of bees on my balcony? An internet search and a chat with Michael’s dad who knows about bees has reassured me. On the plus side, it may be interesting and at least the plants will benefit.