Migration Madness?

Today, the skies were filled with black saddlebags dragonflies.  At first I noticed a few, and by the afternoon we were literally seeing hundreds of them at a time - they don't perch much so no photo... I know they migrate, but I don't know the timing of that.  It seems early, but... it was crazy how many there were.  Really neat.  Kids were just pointing in every direction.