Passenger Pigeon Apocalypse
Three billion is the number of birds lost to North American populations in the last 50 years. It’s also a low-end estimate of the number of Passenger Pigeons that once lived on the North American continent. These birds were said to number so many that flights of them overhead could darken the sky. The fact that humans alone as a species were responsible for this devastating extinction is terrifying but, viewed from a certain angle, hopeful.