Researchers from the University of Hawaii at Manoa credit rats with having driven or assisted 103 species of birds, reptiles, amphibians, and mammals to extinction
Killing Animals to Save Animals: A Conundrum
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The claim of the impending mass extinction of the Earth’s species is a never-ending drama. In 1979, the biologist Norman Myers declared that a fifth of all species on the planet would be gone within two decades. Subsequently, an attempt was made to give these made-up numbers a patina of scientific respectability that was in many ways an even worse abuse of scientific logic and evidence.
In the 1990s, E. O. Wilson cited the so-called ‘species-area relation’ as the basis for predicting that tens of thousands of species were being extirpated a year by habitat loss caused by forest clearing. Wilson popularized various numbers ranging from 4,000 to 100,000 species a year being lost, and these numbers were repeated over and over again in environmental groups’ fund raising literature, in congressional testimony, and in speeches by Al Gore (who in 1993 said that ‘one-half of all species’ could disappear in our lifetime), apparently an extrapolation of Wilson’s pronouncement, reports Stephen Budiansky. Yet, after more than 90 percent of the Atlantic coastal forests of Brazil were cut down, mostly in the 19th century, the actual number of animal extinctions has been zero, even though many of the Brazilian species are highly endemic, found nowhere else in the world. (1)
Dennis Avery notes, “Biologists are again predicting massive species losses as the world warms. But where are the corpses? There have been few findings of extinctions among continental bird and animal species over the past 500 years. The species extinctions have been virtually all on islands, as humans have brought such alien predators as rats, cats, and Canadian thistles to places where they had no natural enemies.” (2)
Indeed, extinctions have been occurring on islands. Acre for acre there is no real estate in the world of endangered life forms more precious than that of the ocean’s islands. Comprising 5 percent of Earth’s landmass, islands have come to harbor one in every five species of bird mammal, and reptile. They have also shouldered 63 percent of all the extinctions recorded during human history. And most of these owed their endangerment to invaders, particularly of then non-human kind, says William Stolzenburg in his fascinating book, Rat Island. (3)
One of the key culprits was the rat. On almost every one of the islands that bore any sign of Polynesians, there were signs of the rat. The rat often traveled with a purpose, as a snack for the long overseas trips and as a self-perpetuating crop of protein to be planted and harvested in the new homeland. The rats were the great enemies of birds, and any bird living or breeding near the ground had but a small chance of existing. (3)
In the United States alone, some fifty thousand alien invaders have been helped ashore and across borders. The invaders include more than a billion rats and one hundred million house cats, the latter of which have been implicated in the demise of perhaps a billion small mammals, lizards and birds every year. US forests are serving as barnyards and feedlots for four million feral pigs. One economic accounting of the invaders’ damages comes to $120 billion per year. (3)
Some additional examples Stolzenburg provides:
- In the Kerguelen Archipelago, a sub-antarctic wilderness of penguins, petrels and albatross, cats at the peak of their killing were calculated to be removing nearly one and a quarter million seabirds per year.
- On Ascension Island in the middle of the Atlantic Ocean, cats delivered by European colonists would by the twentieth century drive a gathering of some twenty million seabirds to within 2 percent of annihilation, the survivors left clinging to the sheerest cliffs and offshore sea stacks.
- On Sirius Point, a cape in Alaska, the number of seabirds killed by rats each year are more than those killed by the Exxon Valdez oil spill. Researchers, when talking about Kiska, an island in the Aleutians, said the invasion of a single rat was a fate worse than any oil spill.
The trails of carnage led from one-acre islands in the French West Indies to the 607 square miles of Hawaii’s Oahu, across the Caribbean, Mediterranean, and Tasman seas, and across the Indian, Atlantic, and Pacific Oceans. Researchers from the University of Hawaii at Manoa credit rats with having driven or assisted 103 species of birds, reptiles, amphibians, and mammals to extinction.
Most folks are familiar with Easter Island, properly know as Rapa Nui because of the Island’s nearly 400 stone statues representing a long-eared legless human male torso, mostly 15 to 20 feet tall, with the largest 70 feet tall and weighing from 10 to 270 tons. For some reason the islanders disappeared. Popular thinking is that Easter Island is a case study of human induced environmental disaster or ‘ecocide’ and this is covered in depth by Jared Diamond in his book Collapse. He depicts native inhabitants triggering the fall of their once flourishing civilization by cutting down all of the island’s trees. (4) However, new research points to a very different story. Rats played a prominent role in the deforestation of Easter Island. Terry Hunt and Carl Lipo suggest that the last tree did not fall because of an ax, but to a feeding frenzy of Pacific rats. The rats proliferated in a predator-free paradise, finding millions of palm trees. A single mated pair of rats, on an island with limitless food and no predators, could double their numbers every forty-seven days, becoming seventeen million in three years. In 2006, Hunt and Lipo published their solution to Diamond’s riddle in the journal Science. “The ecological catastrophe of Rapu Nui had a complex history that cannot be reduced to psychological speculations about the motivations of people who cut down the last tree. Indeed, the ‘last tree’ may simply have died, and rats may have simply eaten the last seeds. What were the rats thinking?” (5)
So, most folks would probably agree that elimination of rats would be a worthwhile venture. However, massacring rats turns out to be more difficult and interesting than one would think. The species has spent millennia avoiding human predators. Even small islands offer countless hiding places. Eliminating rats from such places inevitably becomes an expensive, quasi-military enterprise. Helicopter assaults transpire more than once in Stolzenburg’s book. Since the 1980, Stolzenburg says, people have wiped out invasive predators on more than eight hundred islands around the world. In most of these places, native bird populations have rebounded, so its’ hard to disagree with the eradications. (3)
Yet Solzenburg reports, “Americans have been slow to concern themselves with these figures, certainly if stray cats are any measure. In 2008, in Galveston, Texas, a man who shot one feral cat as it was chasing a rare shorebird was arrested and faced up to two years in jail and a sixty-thousand dollar fine before the charges were overturned. There are now organizations throughout the country actually promoting and feeding feral cat colonies. They are operating very successfully in Hawaii, the US capital of extinction and endangerment, where some of the rarest birds on the planet are still being taken by subsidized cats.”
In Italy cats have prowled the streets of Rome since ancient times, more recently finding refuge with an association of volunteers who have lovingly tended to thousands of strays over the years amid the ruins of a site where Brutus is thought to have stabbed Julius Caesar in 44 BC. But after a couple of decades of tolerated, if not quite authorized occupancy, Italy’s state archaeologists have told the association that it has to go, saying the illegal occupation risks damaging a fragile ancient monument. The cat lovers issued a reply: They have no intention of leaving. What has ensued is a fight that has drawn in a host of city officials, elicited a flood of e-mails from upset cat lovers and revealed a deeper clash between tradition and legality that has tested Rome’s notions of its cultural heritage. (6)
Other Controversial Issues
* Fish and Wildlife officials in Idaho, Oregon, and Washington may continue killing California sea lions preying on salmon near the Bonneville Dam, a federal district court has ruled. John Charles, president and CEO of the Cascade Policy Institute, a free-market think tank based in Oregon, says the entire controversy over salmon in the Northwest is a matter of cultural preference. “Killing sea lions because they eat salmon is a contrived issue.” California sea lions consume approximately 2 percent of the salmon that reach the Bonneville Dam. Critics argue that sea lions consume far fewer fish than are taken by tribal and non-tribal fisheries and far fewer than are killed by dams. (7)
* Oregon Fish and Wildlife officials are seeking federal approval to kill protected birds to protect juvenile salmon. Cormorants are the main avian threat to juvenile salmon in the region. Approximately 70,000 cormorants live west of the Continental Divide, and 28 states already have federal permission to kill cormorants to protect fish species. Research conducted by Oregon State University concluded that predatory birds consume as many as 22 million, or 15 percent of juvenile salmon each year as the fish swim down the Columbia River toward the Pacific Ocean. A colony of 27,000 cormorants nesting at the mouth of the Columbia River does most of the damage. “This request to kill birds to save salmon is just another bizarre consequence of zealous but confused environmentalists meddling with the wilds instead of staying out of it all,” said Tabor Machan, a research professor at Stanford University’s Hoover Institution.” (8)
* A campaign backed by English cattle farmers to kill huge numbers of badgers that can carry a deadly form of cattle tuberculosis has been called off, at least for now. Last year, 26,000 cattle in the country had to be slaughtered after contracting the disease, to a large extent from the badgers. The British government believes that killing badgers would help eradicate bovine tuberculosis (bTB) in cattle. However, comprehensive scientific studies have concluded that opposite—the culls will not help farmers or cattle, and would be disastrous for England’s wildlife. Some scientists even believe the bTB problem will worsen despite culls. (9)
* The northern spotted owl was a major component in decimating the northwest timber industry, yet after old-growth logging was banned on federal lands to protect owls, their numbers are vanishing faster than ever. The bird’s population continues to decline; a 40 percent slide in 25 years. One of the problems are barred owls, a larger, more aggressive species invading spotted owl territory. Barred owls are less selective about the habitat they use and the prey they feed upon and are out-competing northern spotted owls for habitat and food, causing the spotted owl decline. The barred owl either eats spotted owls or kicks them out of their habitat. Now, to save the imperiled spotted owl, the Obama Administration is moving forward with a controversial plan to shoot barred owls. (10)
There is no scientific dispute that extinctions are occurring, that they are occurring at a rate above the natural level due to human action, and that strenuous efforts are needed to protect critical habitats, to eliminate invasive competitors that threaten species, and to prevent over-exploitation. Yet, animal rights activists who are fighting eradication point to a real conundrum: how do humans choose which creatures are more worthy of survival? Most people like rats much less than they like the birds the rat were extinguishing on numerous island, but things get cloudy with other predator species.
Stephen Budiansky notes, “The egregiously bad science that is still being invoked to shore up wholly unsubstantiated predictions of catastrophic mass extinctions is only undermining the credibility of environmentalists, and is already causing a dangerous political backlash that has handed ammunition to those who want to reject any and all evidence of human impacts on the natural environment. (1)
- Stephen Budiansky, “The Teflon doomsayers,” budiansky.blogspot.com, September 26, 2010
- Dennis Avery, “Species safe even if the world warms,” cgfi.org, May 2, 1010
- William Stolzenburg, Rat Island (New York, Penguin Books, 2011)
- Jared Diamond, Collapse, (New York, Penguin Books, 2005), 81
- Terry L. Hunt and Carl P. Lipo, “Late colonization of Easter Island,” Science, 311, 1603, March 16, 2006
- Elizabeth Povoledo, “Strays amid the ruins set off a culture clash,” The New York Times International, November 8, 2012, Page A11
- Alyssa Carducci, “States can continue killing sea lions to protect salmon,” Environment & Climate News, 15, 11, August 2012
- D. Bray Nelson, “Protect salmon by killing birds, officials propose,”, Environment & Climate News, 15, 11, August 2012
- Sharanya Prasad, “Success! temporary reprieve for UK’s badgers,” care2.com, October 26, 2012
- Carolyn Dufurrena, “Predators in black,” Range Magazine, Summer 2012, Page SG7