The Peregrine Falcon (Falco peregrinus) is a magnificent raptor that soars through the air and dives at amazing speeds. With a wingspan of about 40 inches, the peregrine falcon reaches flying speeds of 40–55 mph, and dives at more than 200 mph when striking avian prey in mid-air. Populations began to decline in the late 1940s as a result of pesticide contamination, primarily due to the use of DDT. The chemical pesticide accumulated in the tissues of birds of prey and caused thinning of eggshells so that the eggs often broke during incubation. After several decades of population decline, the peregrine falcon was placed on the endangered species list in the 1970s. The banning of DDT in 1972 and the reintroduction of captive-reared chicks to former breeding sites enabled peregrine populations to recover sufficiently for the American Peregrine Falcon to be delisted in 1999.