Las Vegas Review-Journal (Sunday)
Endangered Hawaiian crow shows a knack for tool use
WASHINGTON — An endangered crow species from Hawaii that already is extinct in the wild displays remarkable proficiency in using small sticks and other objects to wrangle a meal, joining a small and elite group of animals that use tools.
Scientists said last week that in a series of experiments the crow, known by its indigenous Hawaiian name ‘Alala, used objects as tools with dexterity to get at hard-toreach meat, sometimes modifying them by shortening too-long sticks or making tools from raw plant material.
“Tool use is exceedingly rare in the animal kingdom,” evolutionary ecologist Christian Rutz of the University of St Andrews in Scotland, who led the study published in the journal Nature, said in an email.
The ‘Alala (pronounced ah-la-lah) is the second crow species known to naturally use tools. The other is the New Caledonian crow on New Caledonia island in the South Pacific, which uses tools to extract insects and other prey from deadwood and vegetation.
New Caledonian and Hawaiian crows share a common feature: unusually straight bills. The researchers wondered whether the trait might be an evolutionary adaptation for holding tools, akin to people’s opposable thumbs.
Scientists are trying to save the ‘Alala from extinction. The remaining 131 birds are kept in two facilities on the Big Island of Hawaii and the island of Maui.
“A range of factors may have contributed to the species’ decline in the late 20th century, including habitat change and disease,” Rutz said.
Scientists have mounted a captive-breeding program and later this year plan to release captive-reared birds on the Big Island, their former home in the wild, to try to re-establish a wild population.
Humans are the most adept tool users. But our closest genetic cousins, chimpanzees, use stick probes to extract ants, termites and honey.
Capuchin monkeys and macaques use stones to hammer open hard-shelled nuts and shellfish, respectively. Egyptian vultures and black-breasted buzzards use stone tools to crack open bird eggs for food. Even some invertebrates, including digger wasps, hermit crabs and some spiders, use tools.
WASHINGTON — Arctic sea ice this summer shrank to its second-lowest level since scientists started to monitor it by satellite, with scientists saying it is another ominous signal of global warming.
The National Snow and Ice Data Center in Colorado said the sea ice reached its summer low point recently, extending 1.6 million square miles. That is behind only the mark set in 2012, 1.31 million square miles.
Center director Mark Serreze said this year’s level technically was 3,800 square miles less than 2007, but that is so close the two years are essentially tied.
Though this year didn’t set a record, “we have reinforced the overall downward trend. There is no evidence of recovery here,” Serreze said. “We’ve always known that the Arctic is going to be the early warning system for climate change. What we’ve seen this year is reinforcing that.”
This year’s minimum level is nearly 1 million square miles smaller than the 1979 to 2000 average. That’s the size of Alaska and Texas combined.
“It’s a tremendous loss that we’re looking at here,” Serreze said.
It was an unusual year for sea ice in the Arctic, Serreze said. In the winter, levels were among their lowest ever for the cold season, but then there were more storms than usual over the Arctic during the summer. Those storms normally keep the Arctic cloudy and cooler, but that didn’t keep the sea ice from melting this year, he said.
“Summer weather patterns don’t matter as much as they used to, so we’re kind of entering a new regime,” Serreze said.
Serreze said he wouldn’t be surprised if the Arctic was essentially ice-free in the summer by 2030.
“The trend is clear and ominous,” National Center for Atmospheric Research senior scientist Kevin Trenberth said in an email. “This is indeed why the polar bear is a poster child for human-induced climate change, but the effects are not just in the Arctic.”
One recent theory divides climate scientists: Melting sea ice in the Arctic might change the jet stream and weather farther south, especially in winter.
“What happens in the Arctic doesn’t stay in the Arctic,” Pennsylvania State University climate scientist Michael Mann said.