And more importantly, how do you distinguish it from other entrance activity?
I mostly ask because almost every afternoon at least one or more of my four, seventeen day old hives has a big cloud of bee's in front of it and a huge amount of two way traffic at the entrance, easily 20x more bees in the air than at the other hives. This activity goes on for about half an hour at a time before subsiding to normal levels. I don't see anything that looks like fighting at the entrance but it is hard to tell with the amount of bees clogging it.
This is my first year with more than one hive and since my bees are the only (domesticated at least) ones within several miles I never worried about robbing before but now I wonder. I would probably just write this activity off as orientation flights but I thought those where just for new bees and my hives are still to new to have emerging brood. I've been seeing a few wasps around the hives and I've also been wondering if from time to time one gets in and the bees go nuts.
I'm pretty sure that nothing bad is going on but It would be nice to know what the definitive (I know, I know, bee keepers hate the word) signs of robbing are so if and when it happens I can identify it properly and not ignore it.