Displaying items by tag: silent spring

This grounded bald eagle at a wildlife refuge in Missouri eventually succumbed to lead poisoning. Lead from bullets and shot are the latest threat to bald eagles, the recovery of which is an American conservation success story.  Betty Thompson

Once again bald eagles are in trouble: This time the threats are a deadly recipe of lead and neurotoxins.

The recovery of America’s bald eagles is one of the greatest environmental success stories of the past 50 years. From an estimated overall population of about 800 at the depth of their decline, they have rebounded to about 100,000 today living near water in Alaska, Canada and all of the lower 48 states.

Hellbender Press has covered the success story that brought our national symbol, the bald eagle, back from the brink of extinction.

The cause of that long-ago calamity was ferreted out with the help of an early citizen-scientist, a retired Canadian banker living in Florida named Charles Broley, who became interested in eagles and obtained a permit to band eaglets. Between 1939 and 1946 he banded a total of 814 of them in the nest before they fledged.

As the years passed Broley observed a population decline and initially thought habitat loss was to blame. But in an Audubon article he penned in 1958, Broley concluded, “I am firmly convinced that about 80 percent of the Florida bald eagles are sterile.”

But why? Broley was the first to speculate that the use of organochlorine pesticides, most notably dichlorodiphenyltrichloroethane, or DDT for short, was somehow the cause; but he had no proof and didn’t know how the chemical compound actually affected adult eagles.

Broley’s suspicions and others were brought to national attention by Rachel Carson in her landmark 1962 book, “Silent Spring.” DDT was outlawed in 1972 and the eagle population slowly began to recover.

And today? Bald eagles still face problems — both old and new.

The old one is lead poisoning.