Among the greater chunks of powerful evidence for the damage the pesticide DDT did to birds is the dramatic recovery of some species as residual DDT levels drop, after DDT use ended in the U.S.
In 1970 only one nesting pair of bald eagles lived in New York state; I have not found whether they successfully fledged any young that year, but the odds are against it.
47 years later, eagles nest in after-recovery record numbers in New York, according to the venerable Buffalo News.
If you haven’t spotted the stark white head of a bald eagle somewhere in the Buffalo Niagara sky, it might be time to get out of the house more often.
Eagles are back in historically high numbers, according to a recent report by the state Department of Environmental Conservation.
The DEC reported a record-high 442 bald eagle breeding territories statewide in 2016, including 58 spots in six Western New York counties, including Erie, Niagara, Wyoming, Chautauqua, Cattaraugus and Allegany counties. That’s up from 38 spots in the region in 2012.
“It’s an astonishing number,” said Jim Landau, a count coordinator from the Hamburg Hawk Watch.
Recovery of bald eagles, and other endangered raptors including osprey, brown pelicans and peregrine falcons, is a great chapter in the book of successes of the Endangered Species Act and the rising conservation consciousness of the 1970s.
Recovery of all four species waited after EPA’s ban on crop use of DDT, until residual DDT levels in adult birds declined to a point the female birds could once again produce competent shells for the eggs they laid. DDT levels in fish and prey also had to drop to levels that would not poison chicks just hatched.
EPA banned DDT from U.S. farms in 1972, designating all DDT made in the country for export, to fight disease. Though DDT use declined world wide as resistance to the pesticide spread rapidly among mosquitoes and flies that were its target, most diseases DDT fought against declined. I estimate about 100 million fewer people died of malaria alone after the DDT ban. Birds were saved, and so were humans.