A SPECIAL HOUR DEVOTED TO THE NATURAL WORLD THE GREAT MIGRATION - Scott Pelley visits Kenya, the site of the great wildebeest migration, and looks at the threats to this natural spectacle comprised of over a million animals. Henry Schuster and Rebecca Peterson are the producers. THE SECRET LANGUAGE OF ELEPHANTS - Researchers listening to elephant sounds and observing their behavior are compiling an elephant dictionary. Bob Simon goes to Central Africa to listen to the language of the forest elephants first hand. Harry Radliffe is the producer. B-REX - Lesley Stahl meets the inspiration for the lead character in the classic film Jurassic Park and reports on how famed dinosaur hunter Jack Horner is shaking up the paleontology world. Shari Finkelstein and Meghan Frank are the producers.