Summary: <p>One hundred years ago, the last passenger pigeon, named Martha, died in captivity at the Cincinnati Zoo. At the time of her death, she was a bit of a celebrity and the fact that the species was now extinct was shocking to the American public. Not long before Martha died, passenger pigeons flew in packs so large over the U.S. and Canada they could block out the sun for days. But starting in the 1600s, with the arrival of European explorers, humans began killing the birds. And as technology advanced, the killing became a slaughter. For this month's Environmental Outlook, Diane and her guest discuss the passenger pigeon's flight to extinction and what it teaches us about the importance of conservation.</p>
