Today, Sept. 1, marks the anniversary of a dark day in the history of life on our planet and in the history of our species. Sept. 1, 1914 is generally considered the day that the passenger pigeon went extinct. This is the day that the last known passenger pigeon (a female named Martha who was housed at the Cincinnati Zoo) died. For those who are unfamiliar with the story of this species, the passenger pigeon once existed in incomprehensible abundance and was probably the most numerous bird ever—for example, a 19th century naturalist observed an immense mega-flock that he estimated to consist of 2.2 billion pigeons! Yet, in an unprecedented glut of greed and overexploitation humans drove this impossibly numerous species to extinction, and did so essentially within a mere 3 decade period. This is a hugely significant episode, particularly in the important lessons it conveys regarding the impact of our species on the other life on our planet. However, despite the extreme magnitude of this episode it languishes in relative obscurity. It’s surprising how poorly known this story is among the general human populace. For those who are unfamiliar with the story of the passenger pigeon and would like to learn more I highly recommend the book The Passenger Pigeon: Its Natural History and Extinction by A. W. Schorger. Though somewhat dated, this is an amazing work. Schorger’s research on this extinct species was quite remarkable and he uncovered and included many startling, mind-boggling firsthand accounts. For an excellent, more recent book on the passenger pigeon I also highly recommend A Feathered River Across the Sky: The Passenger Pigeon’s Flight to Extinction by Joel Greenberg. In addition to these books I recommend the DVD documentary about the passenger pigeon titled From Billions to None (this is the documentary that aired on PBS stations in the U.S.).