What are the big differences between Crows and Ravens, since the birds look the same to me?

Look at their size. A Crow (Corvus brachyrhynchos) is 17 to 21 inches. A Crow's wingspan is 33 to 39 inches. A Crow weighs 11.15 to 21.89 ounces. A Raven (Corvus corax) is 22 to 27 inches. A Raven weighs 24.32 to 57.36 ounces. A Raven's wingspan is 46 inches. The Raven is larger than a Crow.

Listen to their sounds. A Crow makes a "caw" sound and a Raven makes a deep "croak" or a hoarse "rronk" sound.

Look at their appearance. A Raven has a bigger bill and a shaggy throat. A Raven's bill is more parallel while a Crow's bill has a downward curve. Raven wings are shaped differently than a Crow's wings (longer primaries).

Watch their flight. A Raven may do somersaults when it flies. A Crow does not.

Watch their behavior. A Raven is a scavenger. It follows predators to feed on leftovers. It also patrols the roadways. A Crow forages mostly from the ground and picks through litter.

These birds belong to the Corvidae family and are found all over the world. The distinction between crows and ravens is only to do with their name, they all belong to the same genus (Corvus) so that means they are genetically very similar. In Europe ravens are larger than crow species but in Australia it's the opposite. So there aren't any rules I can find to govern why one is a named a raven and another is a crow.

There are really only two ways to distinguish the Australian crows and ravens. The first is geography. Some species are found in some parts of the country but not in others. For instance, if you see one in Tasmania it will, most probably, be the forest raven as that is the only species that breeds there.

The other method can only be done with dead birds and that is to inspect the hackle feathers . Each species has a different shape.

I admit to checking on Wiki, and after reading the article it remains as clear as mud! So much for higher qualifications in English!

http://en.wikipedia.org/wiki/Corvus_%28genus%29

"The genus was originally described by Linnaeus in his 18th century work Systema Naturae. The name is from the Latin corvus meaning "raven". The type species is the Common Raven (Corvus corax); others named in the same work include the Carrion Crow (C. corone), the Hooded Crow (C. cornix), the Rook (C. frugilegus), and the Jackdaw (C. monedula). The genus was originally broader, as the Magpie was designated C. pica before later being moved into a genus of its own. There are now considered to be at least 42 extant species in this genus, and at least 14 extinct species have been described.

There is no good systematic approach to subdividing the genus at present. Generally, it is assumed that species from a geographical area are more closely related to each other than to other lineages, but this is not necessarily correct. For example, while the Carrion/Collared/House Crow complex is certainly closely related to each other, the situation is not at all clear regarding the Australian/Melanesian species. Furthermore, as many species are similar in appearance, determining actual range and characteristics can be very difficult, such as in Australia where the five (possibly six) species are almost identical in appearance.

Basically, a Raven is larger than a Crow.

They are both highly intelligent, and subject to similar superstitions - though no one would worry if any crows left the Tower of London!

RE- Ravens & Tower of London:

'Raven' is the translation of the Welsh 'Bran', a king of Britain in the Mabinogion. Supposedly, Bran's head was buried on the hill where the Tower of London was later built, and the legend ran that as long as his head remained, Britain would be safe from invasion.

In order from largest to smallest

Raven Crow Blackbird. All the same different sizes

Devo the easiest way to tell the difference to me is listen to the birds. Crow are constantly making the caa caa sound. I don't think ravens make such a noise.

The Crows have the advantage if they're being called alphabetically by name to lunch...

aaaaarrrrr! the one that can hold thar liquor be the largest bird thar matey! SAVVY? ;)