For most people, crows are crows are crows. In fact, most people may have a hard time distinguishing between a crow and a blackbird. So it may come as news to some folks that there are many different kinds of crows around the world. Most of them look pretty similar to each other. In fact, as I've been watching the crows flying around downtown DC for the last couple days, I haven't known which species I was seeing--since there are two kinds of crows in this part of the country. Last night I finally heard the crows calling as I walked back to my hotel, and could tell that they are Fish Crows.
Unlike the common American Crow that is found across most of the United States, Fish Crows are pretty much restricted to waterways and coastal areas along the East and Gulf Coasts from Beaumont, TX to southern Maine. They are called Fish Crows because of their habitat mostly along rivers and waterways. But if you were to call it by its voice, you might call it a Frog Crow...since their caw notes (listen here) sound lower and more like a frog than the caw notes of the common American Crows.
Other than by voice, American and Fish Crows can be hard to tell apart as they look pretty much the same. But when they open their beaks, you can tell the difference. So, next time you think there is something fishy going on in Washington, DC--as long as you're thinking about crows, you may well be right!