The number of bald eagles in the lower 48 states, a population once on the brink of extinction, has quadrupled in the last twelve years to more than 316,000, according to federal wildlife officials. A new survey by the U.S. Fish and Wildlife Service found there are more than 70,000 breeding pairs of the iconic raptor in the contiguous U.S. In the late 1960s, there were fewer than 500.