In this column distributed by the Elon University Writers Syndicate, biology professor Dave Gammon discusses how the recovery of the bald eagle as a species illustrates the resilience of the United States as a country. The column has appeared in Greensboro News & Record, The Virginian-Pilot, The Daily Press and other North Carolina outlets.
The recovery of bald eagle populations over the past half-century is one of nature’s greatest conservation stories.
Even though Benjamin Franklin called the eagle a “coward of rank,” most Americans find the bird inspiring. On the seal of our country, the claws of the eagle grasp an olive branch and a quiver of arrows. Its beak contains a scroll reading “E Pluribus Unum”. Our country is therefore known for peace combined with military force, and unity combined with diversity, values that we certainly need today.
However, from 1963, the existence of the bald eagle was hanging 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 watched a single eagle perched atop a bare tree. No other bird could command as much attention as this American icon on the brink of extinction.
The majestic bird, however, was already on the 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 as of 2020 the Fish and Wildlife Service counted over 71,000 breeding pairs in the continental United States. A staggering 150 bald eagle nests now exist for every nest found in 1963.
Last year my daughter and I saw a mature bald eagle perched a hundred feet from us while kayaking in Maine. A few days later, our family saw another eagle quickly dive a few feet away from us and grab its prey. Only this time it was at a Massachusetts freeway on-ramp right next to our car.
The decline in eagle populations is primarily a result of the use of DDT, a highly effective insecticide that is no longer used in the United States today. Although humans were not harmed by the traces of chemicals sprayed on crops, DDT spilled into rivers and lakes, where it accumulated in the tissues of microscopic algae.
Hundreds of algae have been eaten by organisms living higher in the food web. Most of the algal biomass has been fully digested and returned to the environment. However, organisms could not digest DDT, so the chemical simply accumulated in their bodies. The amount of DDT increased by an order of magnitude for each level of the food web.
Unfortunately, the bald eagle resided at the top of its food web. The eagles accumulated so much DDT that it inhibited their ability to accumulate calcium, thereby thinning their eggshells. Unsuspecting mothers crushed their own offspring. Eagle populations have plummeted.
Thanks to conservationists such as Rachel Carson, DDT was banned in the United States in 1972. Simultaneously, forward-thinking fishermen advocated cleaning up lakes and rivers. These and other environmental actions have paved the way for the dramatic increase in eagle populations. Recovery took a while, in part because it takes four to five years for a bald eagle to reach sexual maturity.
Today, eagle populations still face conservation challenges, such as bird flu and poisoning from eating lead-contaminated prey or carrion in ammunition and fishing gear – a Quick round of applause for hunters and anglers who are willing to pay a little more for the non-lead options.
Despite these hiccups, the overall story of the bald eagle’s recovery is dramatic and wonderful. It offers a glimmer of hope that contrasts with the population decline seen in most bird species.
Let’s celebrate our nation’s birthday in 2022 by searching for our national bird in the wild. Find an open body of water with tall trees nearby, or perhaps a quiet slipway. Next, watch a swooping eagle for prey. Also keep an eye out for their 10ft tall stick nests used to house fuzzy eaglets.
The next century looks bright for our country’s favorite bird. We should be inspired by the resilience of the bald eagle and similarly look to the future of our nation with hope and optimism.