What was the historical peregrine falcon population in North America?
The historical status of the peregrine falcon in North America is not known, but it was probably never common, even when compared to other birds of prey. The limited historical data suggest a best estimate of 3,875 nesting pairs. The decline of the peregrine falcon population in North America began in the 1940s, was most pronounced during the 1950s and continued through the 1960’s into the early 1970’s throughout most of its range. By the time biologists realized the magnitude of the peregrine falcon decline, the population was only about 12% of what it had been prior to the introduction of modern pesticides.
