the entire bird population. Single flocks contai
In 1860 Passenger Pigeons were the most abundant birds in North America, estimated to make up 40% of the entire bird population. Single flocks containing more than 2,000 million birds darkened the skies for hours when they flew over. Some 50 years later in 1914, Martha, the last existing Passenger Pigeon, died in captivity. Within that short span of years one of the most successful species in history had been hunted into extinction.