
Crows are social in nature and interaction with their own kind is important. They mate for life and live in family groups which they protect vigorously. They have been know to chase off predators such as hawks and owls.
Ted Andrews who compiled Animal Speak (The Spiritual and Magical Powers of Creatures Great and Small) writes that the Keynote for the Crow is: The Secret Magic of Creation is Calling, with the Cycle of Power being All day - All Year.
Part of the Corvidae family the crow belongs to the same family of birds as the raven though whilst the crow thrives of the detritus and leftovers of humans, the raven has retreated to secluded clifftop places. However, some of the raven's mysticism and mythology is shared by the crow.
In Roman mythology the raven and crows used to be as white as swans. In fact the white crow watched over Apollo's pregnant lover at Delphos. One day the crow brought bad news to Apollo and was turned black. The connection with watchfulness remains today as they are messengers calling to us about the creation and magic that exists in our everyday world.
http://www.rspb.org.uk/wildlife/birdguide/name/c/carrioncrow/index.asp