I observed something today at the entrance to one of my hives that has mildy concerned: I was watching the apparent normal flow of traffic you'd expect to see on a sunny may afternoon when I notice a larger bee (maybe 30% bigger) approach, much louder and aggressive than the workers who were coming and going in fairly large numbers. He landed in front of the entrance, seemed to act confrontational then went on in. After watching for a while I saw similar sized bees arrive every 1 to 2 or even 3 minutes and also appear to depart on about the same basis. Always buzzing louder, always pushier and more aggressive. Could they be drones from the hive? I observed my other hive and saw no similar activity though the numbers of bees coming and going seemed roughly the same. I have removed my feeders and am still using the smallest hole in my entrance cleats. I hope I'm not being robbed.