bald eagles

The Snail Darter Is Safe | Earth Wise

November 14, 2022 By EarthWise Leave a Comment

The snail darter is a three-inch-long snail-eating fish that was once only found in the Little Tennessee River. When that river was going to be dammed by the Tellico Dam under construction in the 1970s, the snail darter was listed on the endangered species list and the little fish subsequently became the subject of a legal battle that made it all the way up to the U.S. Supreme Court. With the dam project 95% complete in 1978, the Supreme Court blocked further construction, citing the Endangered Species Act. A year later, Congress exempted the project from the requirements of the Act, thereby clearing the way for the completion of the dam.

In order to save the snail darter, biologists transplanted the fish into several other nearby rivers and waterways. In addition, the Tennessee Valley Authority modified the operation of the Tellico Dam to release more oxygen-rich water downstream. Beyond those measures, the river cleanup under the Clean Water Act further aided the fish’s recovery.

In 1984, the snail darter was removed from the endangered species list and was listed as threatened or vulnerable. Recently, the U.S. Department of the Interior officially removed the snail darter from the federal list of threatened and endangered wildlife.

The snail darter is the fifth fish species to be delisted because its population has recovered. It is the first in the eastern United States. With better management of water releases at dams, many other imperiled aquatic species could be recovered.

Overall, more than 50 plants and animals have recovered under federal protection, including American alligators, humpback whales, peregrine falcons, and bald eagles.

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Once at Center of Controversial Case, the Snail Darter Fish Is No Longer Threatened

Photo, posted July 22, 2015, courtesy of The U.S. Fish and Wildlife Service via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Bald Eagles And Lead Poisoning | Earth Wise

February 21, 2022 By EarthWise Leave a Comment

The bald eagle is the national bird of the United States. It was once a common sight over much of the continent but was severely affected in the mid-20th century by a variety of factors, particularly the use of the pesticide DDT, which caused thinning of its eggshells and sterility. In the 18th century, the bald eagle population was 300,000 – 500,000. By the 1950s, there were only 412 nesting pairs in the 48 contiguous states.

The bald eagle was declared an endangered species in the US in 1967 and additional regulations strengthened protections for the bird. The banning of DDT in 1972 was a major factor in the recovery of the species.

Bald eagle populations have been rebounding for decades but another issue is weakening that rebound – lead poisoning from gunshot ammunition. According to a new study published in the Journal of Wildlife Management, poisoning from eating dead carcasses or parts contaminated by lead shot has reduced population growth by 4% to 6% annually in the Northeast.

Bald eagle numbers in the lower 48 states quadrupled between 2009 and 2021 to more than 316,000, according to a report by the U.S. Fish and Wildlife Service. But even though the population has seemingly recovered, some combination of factors such as habitat loss, climate change, infectious disease, and lead poisoning could reverse the trends and lead to population declines.

The hope is that the study could help educate and inform policy on ammunition choices for hunters. There are alternatives such as copper-based ammunition. Human health can also be affected when bullets fragment inside game species and are then consumed.

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Bald eagle rebound stunted by poisoning from lead ammunition

Photo, posted March 28, 2013, courtesy of Ben Johnson via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Birds Are Disappearing

October 16, 2019 By EarthWise 1 Comment

A new analysis, published in the journal Science, reports that the number of birds in the United States and Canada has fallen by 29% since 1970. There are 2.9 billion fewer birds in the two countries now than there were 50 years ago.

The analysis is the most comprehensive attempt to date to look at the status of avian populations. The results were a shock to researchers and conservation organizations.

It is well-known that some bird species have become vulnerable to extinction, but the new study, which surveyed more than 500 species, uncovered steep losses even among such traditionally abundant birds as robins and sparrows.

There appear to be multiple causes for the steep declines. The largest ones are likely habitat loss and the wider use of pesticides. Rachel Carson’s 1962 book Silent Spring warned of the dangers of pesticides and took its title from a world that has lost its birds.

The survey includes 76% of all bird species in the US and Canada, but actually represents almost the entire population of birds. Grassland species have suffered the biggest declines by far, as a result of modern agriculture and development. Pesticides, such as neonicotinoids, make it harder for birds to put on weight needed for migration, delaying their travel.

There are a few bright spots: bald eagles are thriving, and falcon and waterfowl populations are on the upswing. These are species that have been the subject of conservation measures in recent decades.

Stopping the bird decline will require a great deal of effort to defend habitats, restrict chemicals, and redesign buildings. Without that effort, birds will continue to disappear.

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Birds Are Vanishing From North America

Photo, posted April 1, 2012, courtesy of Barry Skeates via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.