a diary of the planet
Vanishing migration
The lowest number of monarch butterflies ever recorded in their Mexican winter home has experts worrying about the future of the epic monarch migration. A new report by the World Wildlife Fund and two Mexican government agencies says this year’s precipitous plunge in monarch numbers is due to the disappearance of the insect’s main food: milkweed. Loss of that plant to urban sprawl and expanding agriculture is literally starving the insects to death. Recent bad weather hasn’t helped. The extreme drought in the U.S. corn belt during the summer of 2012 also wiped out huge numbers of milkweeds. The black-and-orange butterflies now cover only 1.65 acres in the forests of Michoacan state, west of Mexico City. That’s compared to almost 3 acres last year and more than 44.5 acres at the recorded peak in 1995.
Shark kills
Environmental and wildlife advocates slammed Western Australia’s move to begin killing sharks along the Indian Ocean coast at the southwest tip of the country in the wake of seven fatal shark attacks within the past three years. The cull comes as marine biologists worldwide warn that some shark species are becoming endangered due to overfishing and mutilation for their fins. The Western Australia government allowed contract fishermen to place baited hooks on drum lines off popular beaches around the state capital of Perth to kill white, bull and tiger sharks over 10 feet long. The first shark killed was shot and its carcass dumped at sea. A new poll by the UMR research company finds that 82 percent of Australians don’t think the sharks should be killed and say people enter the water at their own risk.
Wildlife drones
The Ugandan Wildlife Authority (UWA) says it will start using surveillance drones to help protect elephants and other endangered animals that have come under increased threat from poachers in recent months. The unmanned aircraft are scheduled to be flying by the end of the year. UWA Executive Director Andrew Seguya told reporters that the drones will catch poachers “while in the act.” More than 11,000 forest elephants were killed over the past decade in Gabon’s Minkébé National Park. At least 300 elephants were poisoned last year in Zimbabwe’s Hwange National Park and their tusks hacked off for the illicit ivory trade.
Ursine adaptation
Polar bears have changed their diets over the past few years to cope with a warmer Arctic climate that has cut them off from their usual prey of ringed seal pups. Since sea ice has been melting earlier and freezing later each year, polar bears have only a short period of time to hunt the seals. This forces them to move to other food on land. Linda J. Gormezano of the American Museum of Natural History and the Hudson Bay Project says she and colleagues have found the bears are now eating more snow goose eggs and caribou. “The bears can basically just walk on land and pick up eggs,” said Gormezano. The bears have also been seen eating more grass along the coast and more berries inland.
Coral sea
Cyclone-Tropical storm-force Cyclone Dylan roared onto Australia’s Queensland coast late in the week. Stormsurge flooding arrived at nearly the same time that astronomical high tides also lifted ocean levels.
Earthquakes
A state of emergency was declared on the southern Greek island of Kefalonia after a 6.1 magnitude quake injured seven people and damaged buildings.
• A number of homes and other buildings were wrecked in central Java by a 6.1 magnitude quake.
• Earth movements were also felt in southeastern Iran, Costa Rica, along the Illinois-Kentucky border and along the Vermont-New Hampshire border.
Ocean athletes
Pennsylvania and Nebraska researchers have disproved a 1936 scientific proposition that said dolphins simply aren’t strong enough to swim as fast as they do, instead relying on hydrodynamic tricks for the ability. Nearly 80 years after Sir James Gray formulated the paradox, using the limited tools available then to estimate the marine mammals’ physiological power, modern measurements have shown that dolphins are up to 10 times stronger than some of the most accomplished human athletes. Frank Fish from West Chester University and Timothy Wei from the University of Nebraska used a tank of compressed air and a garden soaker hose to create a curtain of bubbles to measure just how brawny dolphins really are. The same technique was used to measure the performance of Olympic swimmers. Patterns left in the bubble curtain after the dolphins swam through showed that when cruising at 7.6 mph, the animals generated about 1.4 times the power that a fit amateur cyclist can sustain for an hour. That swimming power rocketed almost 10 times when the dolphins accelerated rapidly.