It was DDT that nearly did in the peregrine falcon, not habitat destruction, not hunters, not egg collectors.
Dr. [Tom] Cade, who said he had been fascinated by falcons from childhood and who did his Ph.D. dissertation on the peregrine and gyrafalcon in Alaska, recalled that at first the peregrine’s plight was mistakenly attributed to overdevelopment, molestation by falconers, collection of its brown speckled eggs by admirers and wanton killing by people who simply did not like falcons. But at a conference at the University of Wisconsin in 1965, experts realized that the crash of falcons was a worldwide problem, and, as Rachel Carson suggested in ”The Silent Spring,” DDT was probably the main culprit.
DDT is an organochloride compound that breaks down into DDE, a highly persistent chemical that is stored in the fat of animals that consume it, especially predators like peregrines that are at the top of the food chain. DDE interferes with the deposition of calcium in the shells of the birds’ eggs, leaving them too fragile to survive incubation by females weighing two or three pounds.
Remarkable story of the dedication of one ornithologist, a successful program to revive an endangered species, and serendipity with a happy ending, in an often-overlooked article by science writer Jane Brody at the New York Times, February 15, 2000.
Junk science advocates claim that DDT did no serious damage to birds; the story of the peregrine falcon indicates that DDT was the major culprit in a worldwide decline of raptors. (This is direct refutation of claims by Steven Milloy and the late Gordon Edwards.)
Apart from the rebuttal points, Brody’s story tells how scientists work, how they make mistakes and recover, and how luck plays a huge role in some endeavors.
Peregrine falcons were delisted from the endangered species list in 2000, due largely to the success of Tom Cade’s captive breeding program, coupled with a decline in DDT in the wild after DDT use was restricted.