In this column distributed by the Elon University Writers Syndicate, Professor of Biology Dave Gammon explains how the recovery of the bald eagle as a species exemplifies the resiliency of the United States as a country. The column was published in the Greensboro News & Record, The Virginian-Pilot, The Daily Press and other news outlets around North Carolina.
The recovery of bald eagle populations during the last half-century is one of nature’s greatest conservation stories.
Even though Benjamin Franklin labeled the eagle “a rank coward,” most Americans find the bird inspiring. On our country’s seal, the eagle’s talons grasp an olive branch and a quiver of arrows. Its bill clutches a scroll reading “E Pluribus Unum.” Our country is therefore known for peace combined with military strength, and unity combined with diversity — values that are certainly needed today.
Yet by 1963, the existence of the bald eagle hung by a thread. Only 417 breeding pairs remained in the lower 48 states, according to the United States Fish and Wildlife Service.
I remember visiting Yellowstone National Park as a child in the 1980s where flocks of tourists peered at a single eagle perched atop a naked tree. No other bird could command so much attention as this American icon on the brink of extinction.
The majestic bird, however, was already on its road to recovery. Eagle populations had quadrupled by the 1980s and would quadruple again by the turn of the century. In 2007 the bald eagle was removed from the endangered species list, and in 2020 the Fish and Wildlife Service counted more than 71,000 breeding pairs in the continental United States. A phenomenal 150 bald eagle nests now exist for each nest found in 1963.
Just last year my daughter and I saw a mature bald eagle perched a hundred feet from us as we kayaked in Maine. A few days later, our family witnessed another eagle swiftly dive within feet of us and catch its prey. Only this time it was at the on-ramp of a Massachusetts highway right next to our car.
The drop in eagle populations resulted mostly from the use of DDT, a highly effective insecticide no longer used today in the U.S. Although humans were not harmed by the trace amounts of chemicals sprayed on crops, DDT washed into rivers and lakes, where it accumulated in the tissues of microscopic algae.
Hundreds of algae were eaten by organisms living higher in the food web. Most algal biomass was fully digested and returned to the environment. Organisms could not digest DDT, however, so the chemical simply accumulated in their bodies. The amount of DDT rose by an order of magnitude for each level of the food web.
Unfortunately, the bald eagle resided at the top of their food web. Eagles accumulated so much DDT it inhibited their ability to build up calcium, thus thinning their eggshells. Unsuspecting mothers crushed their own offspring. Eagle populations plummeted.
Thanks to conservationists such as Rachel Carson, DDT was banned in the U.S. in 1972. Simultaneously, forward-thinking fishermen advocated to clean up lakes and rivers. These and other environmental actions paved the way for the dramatic rise of eagle populations. Recovery took some time, partly because it takes four to five years for a bald eagle to reach sexual maturity.
Eagle populations today still face conservation challenges, such as bird flu and poisoning from eating prey or carrion contaminated by lead in ammunition and fishing tackle — a quick round of applause to those hunters and fishermen who are willing to pay a little more for non-lead options.
Despite these hiccups, the overall story of the bald eagle recovery is dramatic and wonderful. It provides a beacon of hope that contrasts with the population decline found in most bird species.
Let’s celebrate our nation’s birthday in 2022 by looking for our national bird in the wild. Find an open body of water with large trees nearby, or perhaps a quiet on-ramp. Then watch for an eagle diving for its prey. Also, keep an eye out for their 10-foot-tall stick nests used to house fuzzy eaglets.
The next century looks bright for our country’s favorite bird. We should gain inspiration from the bald eagle’s resilience and similarly look toward our nation’s future with hope and optimism.