Posted: 17 Aug 2010 09:56 AM PDT
By Duncan Geere, Wired UK
Spain has a pigeon problem, and some cities are recruiting private pigeon catchers to trap the rats-with-wings using special net catapult devices.
The technique involves two people and a catapult-sprung net device. One person feeds the pigeons to make sure that they are gathered neatly into a small space, while the other angles the net catapult. Once the birds are in place, the net is released over the birds to trap them before they can fly away.
Barcelona city council has declared pigeons to be a "plague" and has issued a tender to catch and cull 65,000 of them over the next 18 months — 25 percent of the pigeon population. This represents a significant markup from last year's already-impressive cull of 40,000 pigeons.
The birds have been singled out for spreading diseases and for causing damage to buildings thanks to their highly corrosive droppings which can damage stone architecture. Most culling methods involve nets and cage traps in the busiest areas and then asphyxiation with carbon dioxide.
Some cities, such as Zamora, employ less aggressive forms of pigeon-removal. Zamora distributes large cages in strategic points in the city filled with wheat to attract the animals. Once caught, the pigeons are subjected to a health check. Sick birds are slaughtered, while healthy ones are moved out of the city. This technique has helped reduce the pigeon population by 80 percent since 2004.
Over in the U.K., we are similarly hostile toward urban pigeons. Ken Livingston declared war on the pigeons when he became Mayor of London in 2000 and passed a bylaw making it illegal to feed them.
Trafalgar Square was once famous for hosting the best-fed pigeons in the land, but repairing the damage to Nelson's Column and the square caused by pigeon droppings costs £140,000 per year. Hawks have been occasionally introduced to the square to scare them away.
Posted: 17 Aug 2010 07:35 AM PDT
A bizarre type of giant land turtle thought to have gone extinct 50,000 years ago survived until recently on at least one small Pacific island.
Dozens of bones found in a 3,000-year-old archaeological site on Vanuatu belong to a previously-undescribed species of meiolaniid, a turtle family that evolved 50 million years ago and resembled walking fortresses.
"This group of turtles is not known to have survived into the presence of humans. Now we can say that they met," said paleontologist Trevor Worthy of Australia's University of New South Whales.
The shell of one early meiolaniid species, known from fossils recovered in South America and named Stupendemys for its size, was 11 feet long and seven feet wide. The more modern Meiolania platyceps, found in Australia and Melanesia, had a relatively small five-foot-diameter shell, and weighed an estimated half-ton. All had armored club tails and horned heads.
For 50 million years these defenses sufficed, but they weren't much use against humans — or so researchers suspected, lacking more than the scientific equivalent of hearsay. "In Australia, these turtles survived from the time of dinosaurs, through the Pleistocene. Then humans arrived. And then there weren't turtles anymore. I'd have thought humans had something to do with it, but there was no evidence," said Worthy.
The bones of the newly discovered species, named Meiolania damelipi and described Aug. 16 in Proceedings of the National Academy of Sciences, tell a clear story. They were found in a mound of animal bones discarded near a village of Lapita, a seafaring culture that 3,500 years ago spread east across Polynesia, Melanesia and Micronesia. The bottom layer of the garbage pile, dated to 3,000 years ago, had many meiolaniid bones. The top layer, dated to 2,800 years ago, had none.
The Lapita would have hunted the slow-moving turtles, burned forests to clear cropland, and brought pigs and rats that ate their eggs. Worthy estimates that Vanuatu could have supported tens of thousands of M. damelipi, but in just 200 years they were gone. And if giant land turtles were on Vanuatu, they were likely found on other Pacific islands, and hunted into oblivion.
This fits a pattern of human-preceded extinction recorded worldwide in large animals — collectively known as Pleistocene megafauna — but especially pronounced in the South Pacific, where every populated island lost between 30 and 50 percent of all animal species. These included giant iguanas, terrestrial crocodiles and dozens of birds. Bones of other now-extinct avian species were also found in the Vanuatu heap.
In tandem with these extinctions, the Lapitan culture seems to have vanished. Their distinctive ornate pottery, found across the western Pacific, disappears from the archaeological record.
As for whether there's a lesson to be learned, "I would have thought the lessons would have been learned already," said Worthy. "But people seem to be kind of slow catching on."
Images: 1) Meiolania platyceps./Australian National Museum. 2) M. damelipi scapula bones./PNAS.
Citation: Megafaunal meiolaniid horned turtles survived until early human settlement in Vanuatu, Southwest Pacific. By Arthur W. White, Trevor H. Worthy, Stuart Hawkins, Stuart Bedford, and Matthew Spriggs. Proceedings of the National Academy of Sciences, published online, August 16, 2010.
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