The bald eagle is not only our nation’s most recognizable natural symbol, and the only eagle found exclusively in North America, it is also the Endangered Species Act’s most prominent success story, and a reminder of how important are the protection of our wildlife, critical habitat and natural resources generally.
Populations of breeding pairs of bald eagles in the lower forty-eight states crashed in the late 1960s to just over 400 pairs, due to hunting, habitat destruction and most prominently, the use of chemical pesticides in agriculture, such as DDT. In a scary process, known as “biomagnification,” bald eagles, being an apex predator at the top on their food chain, and feeding mainly on fish, occasional small rodents and carrion, in other words, wildlife which had themselves absorbed toxins in various forms ultimately from pesticide-laden vegetation or runoff from agricultural fields, suffer highly concentrated, elevated levels of these toxins, negatively impacting birth and mortality rates. Calcium deficiencies caused by the toxins resulted in the thinning of eggshells, which would collapse under the nesting female’s weight, causing a nosedive in successful eaglet births.
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