I pulled up to a lake where there was an very large gathering of various birds. I thought I would scare them off but they all came right up to me - kinda creepy.
It does look like they're on a mission to get you! I love that the one in front is in focus like that with the others blindly following their leader :)
I've had that happen to me as well, they're used to being fed and they think you got the grub..lol. Bet they were disappointed and talked about you and your lack of generosity after you left;)