Bald Eagles: An Environmental Success Story

When I first starting working at the park I noticed Bald Eagles. It was September and they were in full motion. I saw them everywhere; dragging limbs through the sky, on the shores eating carrion, hanging out with the buzzards and making kills on the lake. As I watched these amazing birds questions formed in my mind.

 One nagging question; “Why was there an eagle’s nest here?” On all the maps of our area (northwestern Louisiana) they were described as non-breeding, winter residents. This question was my impetus to learn more about these fascinating, carnivorous raptors.

 My question was easily answered with a little help from Marc at the Cornell Lab of Ornithology. Through e-mail he stated that, “The Bald Eagle is currently increasing its breeding range as fast as any bird in North America”. He explained that most maps simply hadn’t caught up to the eagle’s comeback. I was directed to the website http://www.allaboutbirds.org/guide/Bald_eagle/id. The info on the range map for this site showed our region in purple (non-breeding, winter). However, if you look below that map there is a link to a “dynamic map of e-bird sightings”, http://ebird.org/ebird/map/baleag?bmo=1&emo=12&byr=2009&eyr=2013. This is a wonderful, more up to date, birding internet tool. I found my answer here. After locating the park on this map I saw eagles portrayed as dark purple squares. Sure enough, we were a “hot spot”.  

 Now I was really charged and my research continued. It answered my many questions and unveiled the tumultuous environmental success story of the American Bald Eagle.

 It all started around the 1800s when eagles were thought to be eating domestic chickens, lamb, and cattle. So farmers took to their guns and started doing damage to the population. It is true that eagles will take out small animals in a pinch but they prefer to steal from other birds, eat live fish or carrion (dead things), or plunk an occasional Pouldeau out of the water. There’s also the fact that an eagle can only pick up ~ 6-8 pounds in its talons. So, domestic cattle and sheep? Come on!

 In the mid 1900s it was the fishermen’s turn. The alarm was sounded that the eagles were eating all the salmon. Well, eagles do like fish but an entire salmon population? Not likely. This time the government got involved and offered the public 50¢ to $2.00 for a pair of eagle talons. At that time the eagles took a heavy hit to their population.

By the 1940s there was enough cause to worry about declining eagles that the Bald Eagle Protection Act was enacted. Although we were headed in the right direction, the introduction of a chemical named DDT would be the reason for the near extinction of the species.

 In 1945, around the end of WWII, DDT was introduced to the U.S. DDT is a carcinogenic compound that was used as an insecticide. It was detrimental to eagles in that it affected eagle’s eggs making them so thin that no eaglets could be born. Rachel Carlson wrote Silent Spring in 1962 emphasizing the dangers of DDT to animals. Although it was a remarkable environmental book it did little to stop the use of DDT. By 1963 only 417 nesting pairs of eagles were left. It was at this time that they became listed as endangered species. It wasn’t until 1972 that the U.S. stopped the use of DDT.  Some time passed before the residue from this chemical got out of the environment. Slowly the eagle population began to increase. In 1995 eagles were delisted from the endangered species list to threatened status. In 2007 environmental success occurred. Eagles were removed from the threatened list.

 To date Bald Eagle delisting hasn’t hurt the Bald Eagles protected status or their population growth. They are still protected by federal law under the heading of the Bald and Golden Eagle Protection Act and the Migratory Bird Treaty Act making it unlawful to take eagles for any reason. Currently there are 10,000 nesting pairs of eagles in the continental U.S. There are 200,000 individual eagles now versus about 300,000 that were estimated before their decline. Environmental success stories are hard to come by. Habitat destruction, global climate change, poaching, pollution and displacement by exotic species still remain real threats to our environment. However, if the eagle population can be increased to their near beginning numbers there is hope for many other declining populations.

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About Sunny

Interpretive Ranger
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One Response to Bald Eagles: An Environmental Success Story

  1. Pingback: Golden eagle in the snow, video | Dear Kitty. Some blog

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