Cleared for take off.

I was sitting quietly in the garden enjoying a well earned cuppa 
( well I would say that ) and suddenly became aware of insects lifting off from the ground. On closer inspection it turned out to be colony of  ants emerging from their nest and flying away immediately. I then noticed there were a  further 6/7 sites adding to the airshow. How is this coordinated when 10 minutes before there was no activity at all? Nature is full of surprises.