Are Bald Eagles Still Endangered?
The bald eagle: a national symbol for the United States, and source of pride for many. Eagles are majestic birds of prey that make their homes near many sources of water, even oceans in some cases. There was a time, however, that the bald eagle came very close to extinction because of a variety of inhibiting factors. The good news? Bald eagles are now of least concern in terms of endangered animal status. But how did this change come about? What lead to the bald eagle decline and subsequent rise? For these answers, we need to look at the early history of the United States.
Eagles were abundant in 1700s America, with estimates upwards of 500,000. Bald eagles used to pray on livestock like sheep, goats, and chickens in the middle 1800s. Of course, people weren’t too happy about birds taking human food sources, so they started shooting eagles on site. Which, of course, leads to population decline. Nearly one hundred years later, due to loss of habitat, human intervention, and reduced food sources, bald eagles became increasingly threatened. In the 1940s, Congress passed a law forbidding the killing, owning, and sale of bald eagles. But a different enemy was poised to drive the birds to near-extinction.
You may have heard of this chemical before. It was a post-WWII insecticide and it is extremely effective at keeping bugs off crops. Not only that, but it does an impressive job of killing vectors of malaria. Some countries still use DDT to combat malaria where it is a public health crisis, though the use of DDT in the United States is unlawful. Why? Well, DDT has a soil half-life of, under the right conditions, up to 30 years. This means it’s easy for it to accumulate in the environment and in larger animals through biomagnification.
Walking on Eggshells
This is bad news for birds of prey and other large animals, as they are the biggest losers when it comes to the harmful effects of a detrimental chemical accumulating this way. The bald eagle was especially at risk because DDT (and what it breaks down into over time: DDD and DDE) caused eggshells of these birds to become thinner and therefore nearly impossible to hatch. It also caused sterility in adult eagles, effectively killing young populations. By 1950 there were around 400 nesting pairs of bald eagles remaining.
Bans and Regulations
A social movement spearheaded by activists and scientists such as Rachel Carson campaigned against the use of DDT commercially. It was a major success (DDT was banned in the US in 1972), and the bald eagle now thrives across America and Canada. The grassroots campaign was integral to protecting bald eagles and other large birds harmed by DDT and malicious hunting. Now bald eagles are far from endangered!
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