How many bee's do I have to have in my yard before I call the beekeper?

I pick answer number 1, but I would call the beekeeper now.How many bee's do I have to have in my yard before I call the beekeper?
First of all make sure there bees? Most of the time people mistake yellow jackets as bees, so the bees get blamed for stings given by these wasps. The only time you need to call a beekeeper is when a hive swarms. Then you will see a large cluster of bees usually hanging on a branch.