This is important for all beekeepers
It is amazing how many beekeepers, some with several years "experience", don't know what happens in a colony of bees in the days before and after it swarms. I once gave an all day presentation and a couple who had been keeping bees 20 years simply didn't know. This is one of the basics that in my view should be learnt very early on. If you don't know what happens, how are you going to prevent it, or deal with the colony once it has swarmed? For some reason many don't see the life cycle of the queen as being relevant and don't know that either!
There is a lot written about swarming, but the following is as a result of my observation, which may vary from convention. I have done it in steps for convenience.
The above is what normally happens and is what all swarm control methods are designed to interrupt. The understanding of the swarming process is absolutely crucial to understanding what each method is trying to achieve. It is absolutely pointless trying to follow a system in steps A-B-C.... without knowing what the bees are trying to do. That is an easy way to failure.
I have observed many swarms issuing from hives and queens can emerge very early or very late. There seems to be no consistency.
Less than three eggs/larvae in queen cells may be supersedure cells and a sign there is a problem with the queen.
A colony in the right condition will swarm on all kinds of queen cells, even though they did not originally intend to swarm.
In my experience swarms always cluster where at least two ley lines cross. When they select their final nest site they are also where at least two ley lines cross. I know there are many who simply won't believe this, but that is my experience of several hundred cases, with not one negative.
Some sources suggest it is bees from a clustered swarm that send out scouts - they may do, but I believe the work has already been done and the colony knows where it is going. My thinking is that if you have a pile of boxes with comb in, or an empty hive, there is usually about a week's activity before a swarm arrives. I'm going on my observation.