|American Crow (Image by: DickDaniels, via Wikimedia Commons, CC BY-SA 3.0)|
Technically speaking, a crow is any bird from the genus, corvus. However, the word "crow" is most often used to refer to just a few specific species. In North America, it usually refers to either the American Crow or the Northwestern Crow. In Europe, it usually refers to the Carrion Crow or the Hooded Crow. Most crows are black in color (however, the Hooded Crow is mostly grey), have a wingspan of around three feet, and are around 18-21 inches in length, depending on the particular species. They eat almost anything - fruit, nuts, carrion, eggs, small rodents, amphibians, scraps from garbage, etc. They tend to hang out near humans so they can scavenge. Crows are very intelligent, and are often regarded as some of the world's smartest animals. They make many vocalizations, and are great mimics.
|Common Raven (Image by: David Hofmann, via Wikimedia Commons, CC BY 2.0)|
Most sources will tell you that one of the main differences is that ravens are larger than crows. While this is usually true, it isn't a fool-proof way of telling the birds apart. The Common Raven is generally between 22 and 30 inches in length, and as mentioned above, crows can be as large as 21 inches. Therefore,a large crow can easily be mistaken for a small raven (and vice versa) if you only go by size.
Even so, there are other physical differences you can look for. A raven's feathers are shinier and usually "fluffier" (or appear fuller) than a crow's. A raven's bill is larger and curved closer to the end than that of a crow. Ravens have a slight point in their tail which gives it a wedge shape, while a crow's tail is more rounded. Ravens also look a bit different in flight. They have longer, thinner wings and are likely to be seen soaring. If you see a black bird doing a somersault in the air, you're looking at a raven! If you hear its call, you can usually figure out which bird it is - a crow has a distinctive "caw caw" sound, and a raven's call is deeper and more of a croak. Ravens are also less social than crows and are more likely to live in less populated areas or in parks, though they can adapt to most environments.
Ravens and crows aren't completely different, however. The similarities in appearance are obvious, and both birds have demonstrated problem-solving skills in laboratory experiments and in the wild, which puts them both toward the top of the avian intelligence ladder. They eat similar diets - they are both opportunistic omnivores, even though ravens seem to prefer carrion a little more than crows. Of course, one of the main things crows and ravens have in common is that they are both awesome and fascinating birds.