Traditionally,
Peregrine Falcons nest on ledges of high cliffs in remote
areas. In cities, however, they use recesses along ledges
or in window boxes.
In
the 1960s, scientists discovered that the pesticide
DDT was interfering in the egg shell formation of many
meat and fish eating birds.
Healthy birds were laying eggs with such thin eggshells
that they were crushed by the weight of the incubating
adult.
By 1965, no Peregrine falcons were fledged in the Central
or Eastern United States.
By 1968, the Peregrine Falcon population was completely
eradicated east of the Mississippi River.
In 1972, use of DDT was severely restricted in the United
States and worldwide.
In 1979, the Eastern Peregrine Recovery Plan was developed
to restore a Peregrine population to the eastern United
States.