Crows and ravens may look similar, but they have distinct differences. Ravens are larger with chunkier beaks, longer shaggy feathers on their necks, deeper croaks, and more acrobatic flight patterns.

At the top of a tree in the forest a Crow sat preening his coal-black feathers. He had just finished a meal of nuts and grubs and he was feeling good. 'I must be the happiest bird in the world ...

For decades, conservationists have been trying to save a critically endangered Hawaiian crow ... birds are about the size of a football. They are around 18 inches long and are a duller black ...