* Use of the pesticide DDT (Dichloro-Diphenyl-Tricholor-Ethane) was the primary cause for the Peregrine population to begin to decline and be placed on the endangered list in the early 1970s depending on the state.
Peregrines ate birds that had eaten seeds that had been soaked in the pesticide.
This caused the Peregrine to stop laying eggs, or lay eggs with very this shells.
When the birds tried to incubated the eggs, the shells were so thin they broke.
Pesticide residues become more concentrated as they work their way up the food chain (called "bioaccumulation") and can stay in the environment for years.
* When DDT was banned from use in the US the Peregrine Falcon's population
began to rise again. The use of pesticides is controlled in Canada and the U.S.
but not in Latin America where some of the birds go for the winter.
* In Canada and the U.S. it is illegal to kill or disturb Peregrine Falcons in their nests.
* Peregrine Falcons were removed from the federal endangered species list in August of 1999, however the falcon population is being closely monitored by state wildlife departments especially in Ohio and California.
* Several agencies bred peregrines in captivity and release the young by "hacking".
Birds that are about a month old are placed in a hack box that has been placed on a cliff or ledge of a building. Food is fed to them through a tube so they do not see the human.
Once they can fly and hunt on their own (several weeks later)
the box is left open for them to leave.
