It's hard to believe that in the early 1800's, roughly 40 percent of the birds in North America were passenger pigeons. Yet, a century later, the species was hunted to extinction. The last one died in captivity in 1914.
Naturalist Joel Greenberg has written about this cautionary tale. He will give the Illinois State Museum's Science Series lecture Wednesday in Springfield. His book is titled "A Feathered River Across The Sky: The Passenger Pigeon's Flight To Extinction."