I certainly can’t tell the difference between an American crow and a fish crow by looking at them, though fish crows are a bit smaller. It’s their call that really makes them easy to tell apart. Fish crows have a nasally call, unlike the American crow’s classic “caw.” Though these two species often coexist nicely and even hunt and feed together, during mating season they harass each other as well. In the video below, I think I’ve captured a group of fish crows bothering a few/couple of American crows.