Why are there Thousands of honeybees swarming into a grapevine thats not even started the season?

I have wel into the thousands of honeybees swarming into a grapevine that is not growing anything on it yet for the season. They are all clumping together into massive ball of bees larger than a basketball on a old dried out vine. Why and what should I do?

Call an expert to handle that. Bees in large enough numbers like that could be fatal if provoked. Seriously, I know how to handle bees, and I would tell you, but for your own sake and safety, call a professional.