Peregrine falcon eggs from 1899 (Falco peregrinus anatum). Field Museum of Natural History, Chicago. FMNH catalogue no.6844. The Peregrine falcon was brought nearly to extinction in the mid 1960s, primarily by exposure to DDT and other pesticides. The species became extinct in the eastern USA. In use as a pesticide since 1939, DDT caused thinning of eggshells and a resulting crash in hatch rates. Reintroduction programs became very successful as DDT was banned in 1972 and the Peregrine was removed from the U.S. Endangered Species List in 1999. As a cliff dweller, the Peregrine has been very successfully reintroduced into cities, where it nests on building ledges and other structures and hunts pigeons and other birds. Specimens in museum collections, such as these eggshells collected in 1899, provided a baseline shell thickness, evidence of the thinning of eggshells caused by DDT.