The American Peregrine Falcon: An Endangered Species

Figure 3: An American Peregrine Falcon catching its prey, a pigeon.

     The American Peregrine Falcon was listed as an endangered species in 1970.  Human efforts to control pests led to the American Peregrine Falcon's decline.  DDT used to be used as a pesticide in the United States as well as other parts of the world.  Over time it was found that DDT poison is passed through the food chain and accumulates in the bodies of tertiary consumers.  DDT in the bodies of the American Peregrine Falcon causes the eggs to have soft shells.  When the birds lay on their eggs to keep them warm, they end up smashing the soft eggs.  The American Peregrine Falcon's populations declined because they could no longer reproduce effectively.
     When DDT was found to be the cause of brittle egg shells, it was banned from the United States.  Listing the American Peregrine Falcon as an endangered species helped their comeback in the United States, by protecting their nesting areas and allowing them to reproduce without human interference.  Our efforts to save the species have paid off.  In 1999 the American Peregrine Falcon was taken off the federal endangered species list, but it is still fully protected in California.