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Old 03-28-2013, 12:48 PM   #1 (permalink)
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Cliff Swallows Evolve to Avoid Traffic

Ok, it's not really "ecomodder discussion", but I thought a lot of people would find it interesting. It seemed like posting it in "Off-Topic Tech" fit best, but I had considered Aero since it's about aerodynamic/turning radius improvements for birds with shorter wings. At any rate, enjoy!

Cliff swallows that build nests that dangle precariously from highway overpasses have a lower chance of becoming roadkill than in years past thanks to a shorter wingspan that lets them dodge oncoming traffic. Thatís the conclusion of a new study based on 3 decades of data collected on one population of the birds...

When the researchers looked back at the numbers of swallows collected as roadkill each year, they found that the count had steadily declined from 20 birds a season in 1984 and 1985 to less than 5 per season for each of the past 5 years. During that same time, the number of nests and birds had more than doubled, and the amount of traffic in the area had remained steady.

The birds that were being killed, further analysis revealed, werenít representative of the rest of the population. On average, they had longer wings. In 2012, for example, the average cliff swallow in the population had a 106-millimeter wingspan, whereas the average swallow killed on the road had a 112-millimeter wingspan.
Cliff Swallows Evolve to Avoid Traffic | Wired Science |

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