Ravens: The intelligent bird synonmous folklore and history
Bad omen? Tower of London raven missing, feared dead, London
Identify crows Wildlife Watch
BBC - Nature UK: Have you been seeing ravens where you live?
Wild Birds Unlimited - Nature Shop
Ravens cleared over collapse of waders, The Independent
Hooded Crow - British Birds - Woodland Trust
British crow family guide: identification, habitat and species facts
Brains and brawn' have allowed crows and ravens to thrive almost anywhere in the world