Flyweight contest

I had only these two flies to entertain me when I checked my moth trap in the rain this morning. I'm not sure of the species, but I got the impression that the large one did not have the best of intentions towards the little one. Luckily for it, my probing lens, as I tried to get a better shot, scared the big one off and the little one carried on its business seemingly unperturbed. A mini-drama before breakfast!