A Success Story: The Peregrine Falcon

After nearly 30 years of being on the Endangered species list, the peregrine falcon (species name: Falco peregrinus) was de-listed on August 20, 1999. Their story of near extinction turned around to a healthy population is extraordinary.

Their story began after World War II. At this point, there were more than 3,800 nesting pairs. The falcons had a natural range that spread over most of North America from Alaska to parts of Mexico. They mate for life so the number of breeding pairs is important in our look at these raptors. "Widowed" falcons will not take another mate, so only mating male and female birds can be used to monitor their ecological health. A sudden drop in their population was most prevalent in the 1950's after widespread use of a chemical known as DDT.

DDT is a chemical used to kill insects. DDT breaks down into DDE, a toxin that makes bird eggshells very thin. DDE stays in the environment for a long time and as insects die from DDT, the metabolite DDE stays in fish and birds that eat those insects. Those birds and fish are eaten by raptors such as the peregrine falcon. This makes DDT a grave danger to predatory birds.

Falcon eggs became so thin, that they would break when the mother falcon incubated the eggs. Due to this, the peregrine falcon population got smaller and smaller until there were no more in the eastern U.S.. The western population was not faring much better. The numbers of mating pairs had declined by more than 80%. In 1970 the species was listed as Endangered under the Endangered Species Conservation Act of 1969. The population of the falcon hit an all-time low in 1975, when only 324 nesting pairs resided in the U.S..

In less than 25 years the falcon has been able to return from nearly dying out. This was not simply nature's cycle. It was helped along by governmental regulations, and concerned citizens that used their time to help the falcon succeed. Several factors helped the falcon increase its numbers. Banning DDT, Captive breeding programs, and reintroduction efforts all played a role.

The most accredited of these is the ban of DDT in 1972 by the Environmental Protection Agency. It banned the use of DDT, thereby ensuring that no more of the toxic pesticide could be put into the environment to harm wildlife. This was a highly controversial decision that some still argue today.

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