Bird Mystery

I've been watching birds and wondering. This guy stands on that light post for hours everyday. I watch. Other birds fly around and try to land. He opposes them and they go. Birds want to land but are not allowed. Could be multiple birds attempting to join and this one guy manages to shoo them away.

I look at these birds and they are all the same size. If they were to switch places or share the spot, I couldn't tell them apart from each other easily. They are all very similar, but yet one dictates what's what. Why do the other birds back off? They are the same size. They have the same beak. The same claws. The same stick legs. The same bird brain.

Since the physical is the same, what is the determining factor that sets one bird above another? I don't think they go through any martial arts training, no birds are hiding any weapons in their feathers, and certainly one bird does not lift weights while another sweats to the oldies with Richard Simmons. Is it just attitude? Can one bird give a scarier stink eye than another? Is one bird a certified bad boy and another just a bird without a badge? How is rank and superiority decided?

I can't figure it out. It's a bird mystery!