When I was much younger, my uncle and I would shoot crows in western Kansas. In several counties, there was actually a bounty on the winged black vermin. These crows were so thick, when a flock of them landed on the highway, it looked like the road was moving. Crows behave much differently in large groups. In fact, they are almost stupid! My uncle and I would line up 2 or 3 birds at a time to see how many we could kill with one .22LR. I never got more than 2 at a time, but Uncle Gary put down 3 at once on several occasions.
When they are alone or in pairs, these birds are very wary and cagy. I guess people are somewhat the same. Put them in large groups (soccer fans, for example) and they get stupid, too!
Ron