I keep a daily watch on my hive and saw something last evening that concerned me - fighting bees at the hive entrance and on the landing board. Seems pretty evident that I have some degree of robbing/attempted robbing going on, but my hive is not being overrun. Every few minutes or so I see some bees tussling and it's obvious that my bees are trying to forcibly remove the intruders (sometimes the bees even tumble to the ground or fly off while fighting).
Any suggestions on what i should do and how much of a problem I have? I put in the entrance reducer this morning (so the entrance is now only half the width of the hive), but I know that this is also going to reduce ventilation as well (fortunately our 3 days of 90+ degree temps are gone). I don't think that my hive is particularly weak - I started from a package in April but I now have 2 deep brood boxes and a honey super on and the population of the colony seems robust. Is this type of robbing something that will eventually go away (invaders will eventually give up if my hive can defend itself), or is there a real danger this will get much worse? I am not sure how to proceed.