cats

Raccoons in Europe

July 25, 2025 By EarthWise Leave a Comment

Tens of thousands of raccoons live in Kassel, a city of 200,000 people in central Germany known for its art scene. Overall, there are an estimated 1.5 million raccoons in Germany. The omnivorous mammals are native to North America, but they were brought to Germany in the 1930s for fur farming. Fur farming ultimately ceased but escaping animals and intentional releases ultimately led to a large wild population of raccoons in the years afterward.

Raccoons have gradually made their way across Europe with animals spotted in France, Denmark, Poland, Italy, Austria, and elsewhere.

The people of Kassel have embraced raccoons. In fact, the place is often called the raccoon city. Several sports teams are named after the animals. Many people feed them, and they are pretty much everywhere. On the other hand, residents have to lock up their trash receptacles and they have to check under their cars before driving places.

Since 2016, the EU has classified racoons as an invasive species because of the threat they pose to native wildlife. There are no equivalent species like them in Europe. So, they are a threat to ground-nesting birds, bats in caves, amphibians, and more. They are able to eat almost anything.

What to do about raccoons in Europe is unclear. Despite their popularity in Germany, 200,000 raccoons were culled last year. But raccoon supporters argue that minks, which are native to Europe, and especially cats, are responsible for much of the pressure on species racoons are accused of consuming. Meanwhile, Kassel citizens continue to enjoy their raccoons.

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Rampaging raccoons: how the American mammals took over a German city – and are heading across Europe

Photo, posted December 20, 2016, courtesy of Big Cypress National Preserve via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Making wind turbines safer for birds

September 18, 2024 By EarthWise Leave a Comment

There are people who oppose the installation of wind turbines for a variety of reasons. It is true that wind turbines can be dangerous to birds. Estimates are that about 250,000 birds are killed flying into wind turbines each year in the U.S.

However, this data needs to be looked at in comparison to bird deaths from flying into electrical lines (25 million), vehicles (214 million), and building glass (at least 600 million). And even these figures pale in comparison to the more than 2 billion birds killed by domestic cats each year.

Despite these facts, it would still be great if fewer birds died from flying into wind turbines. Researchers at Oregon State University are part of a team looking at reducing bird collision risks from wind turbines by painting a single blade of the turbine black.

Recent research in Norway found that painting a single turbine blade black reduced the number of bird collisions by nearly 72%. Why should this work? The hypothesis is that the black-painted blades disrupt the visual uniformity of the airspace around the turbines and makes them more noticeable to birds, which prompts avoidance behavior.

The Norwegian data is based on a relatively small sample size and the Oregon State researchers as well as others in Spain, Sweden, and South Africa are working on more rigorous and comprehensive studies.

The hope is that this rather simple strategy could make windfarms safer for birds. Unfortunately, this approach is not likely to be very effective with bats, which rely more on auditory cues rather than visual cues.

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Scientists studying impact of painting wind turbine blade black to reduce bird collisions

Photo, posted May 21, 2024, courtesy of Roy Harryman via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Buildings and birds

November 29, 2023 By EarthWise Leave a Comment

Birds face a wide range of dangers. Billions of them each year face violent deaths. Concerned individuals point at such things as wind turbines, which in fact do kill hundreds of thousands of birds. But the great majority of bird deaths are caused by cats. And that’s a danger that isn’t going to go away.

The second largest cause of bird deaths is collisions with building windows. Building collisions kill hundreds of millions of birds each year in the U.S. alone. As other places have seen glass skyscrapers proliferate, such as in Chinese cites, these collisions have become a major global factor in bird mortality.

There are growing efforts across the U.S. and Canada to reduce bird collisions. Many businesses are taking part in “lights out” programs in which their buildings dim lights during spring and fall migrations. Some buildings now use special glass that birds can see and avoid. Some communities even have adopted ordinances that require bird-friendly glass in new construction. Keeping bird attractants away from windows is another important way to reduce bird strikes. All these measures have been proven to be effective in reducing the number of bird collisions.

Companies sell vinyl film with tiny dots that can be affixed to windows. Both businesses and homeowners have seen substantial reduction in bird collisions with such films installed.

Bird collisions are not a new problem but is one that wasn’t really taken seriously until at least the 1970s. There isn’t much to be done about the greatest threat to birds – namely cats – but how buildings are constructed and operated is something we can control.

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As Bird Kills from Buildings Mount, Cities Look for Solutions

Photo, posted December 24, 2017, courtesy of Nicolas Vollmer via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Humanity Weighs On The World | Earth Wise

April 6, 2023 By EarthWise Leave a Comment

There are countless ways in which humankind has had disproportionate effects on our planet and most of those effects have been negative. A recent study led by the Weizmann Institute of Science in Israel looked at the total combined weight of various groups of mammals on Earth. The results are that human beings and our domesticated mammals are the overwhelming majority of the total mass of mammals.

We think of large land mammals – elephants, bears, bison, wildebeests, and so on – as adding up to a massive amount of animal matter. The study determined that all wild land mammals put together add up to about 22 million metric tons. Wild marine mammals – such as dolphins and whales – add up to about 40 million tons in total. These sound like pretty big numbers until we look at the human and human-created side of the equation.

The study found that humans weigh about 390 million metric tons, while domesticated mammals – like sheep, cows, and pigs as well as dogs and cats – weigh about 630 million metric tons combined.

All told, wild mammals account for only 6% of all mammals by weight. People and their domesticated animals make up the other 94%. This enormous imbalance is an indication of how profoundly humans have reshaped life on Earth. House cats total twice the weight of African elephants and pigs add up to twice the weight of all wild land animals combined.

The conclusion to draw from the big picture here is that wild animals on Earth are not doing very well. We already knew this from many other perspectives, but this census by weight presents a stark picture of the extent to which we have taken over the planet and its ecosystems.

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Total Weight of Wild Land Mammals Less Than One-Tenth Weight of All Humans

Photo, posted December 27, 2006, courtesy of Nigel Hoult via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

The Cost Of Invasive Species | Earth Wise

May 7, 2021 By EarthWise Leave a Comment

A new study published in Nature has tried for the first time to put a price tag on the impact of invasive species. Researchers have been studying the effects of invasive species for decades, but it is a problem that has not really captured the attention of the public and policy makers.

According to the research by scientists at the French National Museum of Natural History, from 1970 to 2017, invasive species have cost the global economy at least $1.28 trillion dollars in damages and efforts to control them.

The team screened over 19,000 published papers, ultimately analyzing nearly 2,000 that detailed costs of various invasions at particular times. Annual costs roughly doubled every six years, reaching a yearly bill of $162 billion in 2017.

The five costliest invasive species are Aedes mosquitos, rats, cats, termites, and fire ants, collectively accounting for a quarter of the global damage.

Asian tiger mosquitos and yellow fever mosquitos alone accounted for $149 billion in damage to public health as they spread from country to country. Rats hitchhike on human boats and drive native species to extinction on islands around the world. Cats inflict damage primarily by their impact on native biodiversity. By some estimates, they kill a billion birds each year in the US alone. Termites, as they spread across the globe, wreak havoc on all sorts of infrastructure. Fire ants can feed on a variety of seedlings, from citrus to soybeans, reduce the size of grazing lands for livestock and bite and sting farm animals and humans.

The study shows invasive species are a massive problem that is getting worse.

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Invasive Species Cost Billions of Dollars in Damages Annually, Researchers Find

Photo, posted March 29, 2012, courtesy of Aleksey Gnilenkov via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Assisting Evolution | Earth Wise

March 11, 2021 By EarthWise Leave a Comment

As plants and animals around the world grapple with climate change, invasive species, disease, and other threats, conservationists grapple with the issue of what it means to protect what is natural and how far to go to prevent extinctions.

Australia is where many of these issues have risen to the forefront. Imported mammals – particularly cats and foxes – have decimated many of Australia’s indigenous marsupials. Much of the focus for decades has been on killing off the invaders and cordoning off protected animals. In recent years, however, there have been efforts to expose prey animals to limited numbers of predators to develop prey populations that are better equipped to survive among predators. Getting rid of all the predators is not realistic. Saving species may require helping them to adapt.

On the Great Barrier Reef, where half its coral populations have perished because of rising water temperatures, scientists are breeding corals that are more heat tolerant. They are even considering the use of gene editing technology to “assist evolution” in developing corals that can survive in a changing world.

At SUNY College of Environmental Science and Forestry in Syracuse, New York, researchers have produced a genetically modified American chestnut tree that is resistant to chestnut blight, the fungal pathogen that killed off nearly every chestnut tree in North America in the early 20^th century.

The idea of conservation is to protect what is natural in our world. However, at a time when there are unprecedented threats to so many species, the distinction between what is natural and what is artificial may no longer provide a sound guide to what should be done to protect life on earth.

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Assisting Evolution: How Far Should We Go to Help Species Adapt?

Photo, posted November, 2000, courtesy of Bernard Dupont via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Exotic Pets Can Become Problems

August 26, 2019 By EarthWise Leave a Comment

Each year, millions of exotic animals are sold as pets around the world. The term “exotic” lacks a set definition but is generally used to refer to an animal that’s wild or more unusual than standard pets, like cats and dogs.

The exotic pet trade is a multi-billion dollar industry, involving tens of millions of individual animals from thousands of species, including reptiles, amphibians, fish, birds, and mammals.

Some of the exotic pet trade is legal, but a lot of it isn’t. Many animals are illegally captured from the wild to meet the global demand for exotic pets.

People often purchase exotic animals without completely understanding the consequences. Some exotic pets, for example, can live nearly twice as long as the average dog. Caring for exotic pets can be both expensive and risky, since they are largely undomesticated (and therefore can have unpredictable behavior).

As a result, it’s not uncommon for owners to release exotic pets intentionally. When this happens, the consequences can be catastrophic. Sometimes the animal dies from starvation or predation, but in other instances, the animal proliferates and becomes an invasive species.

Invasive species are the second largest driver of biodiversity loss worldwide, and they cost the U.S. $120 billion a year.

According to an academic review recently published in the journal Frontiers in Ecology and the Environment, the exotic pet trade is one of the primary causes of the spread of invasive species and has fueled the establishment of hundreds of them. Tegus, Burmese pythons, and red lionfish are examples of pets-turned-pests.

The best way to combat this trend is through education, detection, and rapid response.

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Why you should never release exotic pets into the wild

Photo, posted September 19, 2010, courtesy of Mike Baird via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Saving The Siberian Tiger

March 13, 2018 By EarthWise Leave a Comment

The northeastern part of China, wedged between North Korea to the south and Russia to the northeast, is home to two highly endangered big cats: the Siberian tiger and the Amur leopard. Siberian tigers, which can weigh over 600 pounds and grow to more than 10 feet in length, now number only about 500 in the wild, mostly in Russia. Amur leopards, weighing more than 100 pounds and growing to more than four feet in length, number only about 80 in the wild. While both species are right on the edge of extinction, both are slowly rebounding.

Natural Mosquito Repellents

June 20, 2017 By EarthWise

With summer comes mosquitoes and our desire to keep them away from us. The most common repellents are based on the chemical DEET, which unfortunately has been found to have several health and safety problems. Up to 15% of DEET is absorbed through the skin directly into the bloodstream. Diethyl-meta-toluamide, the chemical name for DEET, has been shown to have a variety of toxic effects. Fortunately, it turns out that there are some natural alternatives which may be as effective as DEET, or possibly even more effective than DEET in keeping mosquitoes away from us.

Can Cheetahs Survive?

January 24, 2017 By EarthWise

A new study has revealed that the global population of the world’s fastest land animal – the cheetah – is down to only 7,100, a drop of 50% over the past 40 years. The dramatic decline in cheetah population could soon lead to the extinction of the species unless urgent conservation efforts are made.