In the 1960s and 1970s, the bald eagle spiraled dangerously toward extinction as contamination by the pesticide DDT and other toxins fatally weakened their eggs.
Our national symbol had instead become a symbol of environmental devastation.
A ban on DDT, the Endangered Species Act and other laws have helped resurrect this wonder of nature to the benefit of Maine and the rest of the country. Now there are more than 7,000 nesting pairs of Haliaeetus leucocephalus (“white-headed sea-eagles” in Greek) nationwide. Maine’s 400 pairs represent 90 percent of the species’s reproductive capacity in New England.
Workers at Bath Iron Works watch eagles ride ice floes down the Kennebec each winter, tearing into whatever they can catch or steal. The birds soar over the St. John Valley in northern Aroostook and fish the Penobscot in Bangor.
They are a natural treasure for the entire state, as much a part of Maine’s enchantment as its moose, loons, coastline and forests.
Yet as top predators, bald eagles remain a barometer of the environment.
Biologists today are studying Maine’s eagles to determine the effects of pollution on them. Researchers are examining the birds for a variety of contaminants including mercury, dioxin and pesticides.
Their work is just as valuable now as it was during the eagles’s decline. While DDT no longer threatens them, the mercury that accumulates in fish still does. Some studies have shown that mercury, a deadly neurotoxin, can impair eagles ability to fly, to hunt and to reproduce.
Maine leads the way in the regulation of mercury disposal, but it’s a topic that sorely needs more attention nationally.
Eagle researchers are trying to make sure the country guards against repeating past mistakes.
Like DDT, mercury has no rightful place in our national symbol.