Run-of-the-mill city pigeons, known as rock doves, build their nests in the nooks and crannies of the concrete cityscape, reminiscent of their native European and Middle Eastern cliffside habitats. Parents typically keep babies, or squabs, hidden and safe until they can survive on their own, usually a month after hatching.

As a result, youngsters are almost fully grown and their feather coloring looks nearly identical to an adults by the time they fly the coop, says Karen Purcell, who leads Cornell Universitys Project PigeonWatch, a grassroots study of feather colorings.

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The fishing industry discards thousands of tons of salmon sperm every year (it ruins the taste). Now Andrew Steckl, a photonics expert at the University of Cincinnati, has figured out how to use the refuse to get a 10-fold boost in the brightness of the organic light-emitting diodes used in cellphones, PDAs and some TVs.

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One common complaint about wind turbines is that they blemish the scenic countrysides and coastlines where they perch. Now an architect in London has an attractive solution. The wind dam, a giant swath of fabric connected to a turbine, looks more like a Christo art installation than a power generator.

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This month, 69-year-old Japanese sailor Ken-ichi Horie will attempt to captain the worlds most advanced wave-powered boat 4,350 miles from Hawaii to Japan. If all goes as planned, hell set the first Guinness world record for the longest distance traveled by a wave-powered boat and, along the way, show off the greenest nautical propulsion system since the sail.

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Its hard to tell what kind of wars the future will bring, but one thing is certain: Robots will be doing much of the fighting. In fact, they already are. Last year, aerial drones flew 258,502 hours of missions—up from 27,201 in 2002. Spending on unmanned aircraft systems by the U.S. military is expected to hit $3.76 billion by 2010. Robotic warfare, long the stuff of science fiction, is now a reality.

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For any vehicle—airplane or car—to fly, there needs to be some force pushing it up so that it can overcome gravity. Airplane wings are specifically designed to create just such a force. As a plane moves forward, the wings push air down, and because for every action there's an equal and opposite reaction, this action creates an upward force on the wing, called lift.

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In the international alliance to fight climate change, the United States is considered the sullen loner. But in the seven years since we rejected Kyoto, changes have begun. Not at the federal level, however. Its the locals who are making it happen.

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In 2006, David Holtzman decided to do an experiment. Holtzman, a security consultant and former intelligence analyst, was working on a book about privacy, and he wanted to see how much he could find out about himself from sources available to any tenacious stalker. So he did background checks. He pulled his credit file. He looked at Amazon.com transactions and his credit-card and telephone bills. He got his DNA analyzed and kept a log of all the people he called and e-mailed, along with the Web sites he visited.

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