Peregrine falcon populations have undergone a remarkable turnaround since the introduction of pesticides such as DDT and human persecution contributed to a severe decline in peregrine numbers. In 1965 they were completely extirpated in eastern North America, but today, thanks to restrictions on the use of DDT, legal protection and an immense reintroduction effort by the Pennsylvania Game Commission and many others, peregrine populations have increased and continue to recover.

The peregrine falcons in Pittsburgh — once the only peregrines known to breed in western Pennsylvania — have been breeding here since 1991 or before and at least one Pittsburgh nest has produced young every year since then. The falcons are helped by the preparation and maintenance of nest sites at the Gulf Tower in downtown Pittsburgh and at the Cathedral of Learning on the University of Pittsburgh campus in Oakland, and by the good will and support of building managers and many concerned local citizens.