A look at the travelers across the "Pacific flyway" - ducks, geese waterfowl A mass migration is taking place in the western U.S. – millions of birds, duck, geese and water fowl are blanketing fields and wetland across California after traveling on what is known as “the Pacific flyway.” The 4,000 mile super highway links the Artic and South America. John Blackstone takes a look at the natural marvel.