Along the vertiginous cliffs of Lake Superior's North Shore, a remarkable Minnesota conservation success story is unfolding. Peregrine falcons, once extirpated from the state, now swoop, dive, and nest at some of the same sites they disappeared from decades ago. The birds were among the victims of contamination by DDT, an insecticide that decimated many raptor populations before it was banned in 1972. A restoration effort led by The Raptor Center and the Bell Museum and including the Department of Natural Resources' Nongame Wildlife Program brought the birds back. They were released in southern Minnesota in 1982 and returned to nest on the North Shore in 1988. Now more than 20 pairs, monitored and banded annually by the Midwest Peregrine Society, nest along the shore.