Ravens role in the ancient times

From the text:

"Those were crows! And nasty suspicious-looking creatures at that, and rude as well. You must have heard the ugly names they were calling after us. But the ravens are different. There used to be great friendship between them and the people of Thror; and they often brought us secret news, and were rewarded with such bright things as they coveted to hide in their dwellings.

"They live many a year, and their memories are long, and they hand on their wisdom to their children. I knew many among the ravens of the rocks when I was a dwarf- lad. This very height was once named Ravenhill, because there was a wise and famous pair, old Care and his wife, that lived here above the guard-chamber. But I don't suppose that any of that ancient breed linger here now."