or a wooden block, he could answer "Wool" or "Wood" correctly, approximately 80% of the time. Alex could identify the difference between yellow and green same-sized objects by saying "Color" or identify a larger one by naming its color. If asked what the difference was between two identical blue keys, Alex learned to reply, "None" (he pronounced it "Nuh"). Alex died on September 6, 2007. "Prudle" held the Guinness World Record for many years as the bird with the largest vocabulary - a documented 800 words. "N'kisi", another grey parrot, is noted for his impressive English usage skills and other abilities. As of January 2004, he had a documented vocabulary of 950 words. N'kisi is believed to be one of the most advanced users of human language in the animal world. "Einstein" appeared on many television shows and became famous for his ability to recreate sounds as well as talking. Video clips show him making the sound of a laser beam generator and an evil-sounding laugh. He has been trained by Stephanie White. Grip was a raven kept as a pet by Charles Dickens. She knew several phrases, including "halloa, old girl", and was the basis for an integral character in Dickens's novel Barnaby Rudge. On more than one occasion, Grip's untimely utterances affect the course of the narrative. Grip was the inspiration for Edgar Allan Poe's poem The Raven. In fiction Talking birds are used as a plot element in fiction, notably in many works by Gabriel García Márquez. Parrots In The Mystery of the Stuttering Parrot by Robert Arthur Jr., the young protagonists look for a group of talking birds, each of whom gives a cryptic clue to the location of a valuable treasure. They are used to humorous effect in the Tintin books The Broken Ear, Red Rackham's Treasure and The Castafiore Emerald by Hergé. In Puck of Pook's Hill by Rudyard Kipling, a grey parrot lives aboard Witta's ship. "When first we entered there a loud voice cried, 'Out swords! Out swords! Kill, kill!' Seeing us start Witta laughed, and showed us it was but a great-beaked grey bird with a red tail. He sat her on his shoulder, and she called for bread and wine hoarsely, and prayed him to kiss her.' "Captain Flint", named for a notorious deceased pirate captain, is Long John Silver's talking parrot in Robert Louis Stevenson's novel Treasure Island (1883).