Bernd Heinrich's "Ravens in Winter" and "The Mind of the Raven" are excellent--
"'Klaus told me that whenever he gets mail, Jakob demands his fair portion of it,' says Heinrich, adding that it is Jakob's pleasure to shred junk mail into confetti. Jakob also insists on being given, for his destructive pleasure, cardboard boxes and mail-order catalogs. Finishing them off, Jakob gives Heinrich a mighty peck on the thigh. 'I was told he wanted the ballpoint pen with which I was taking notes,' he reports, informing us that he quickly surrendered the pen. "