Some estimate that 6 billion Passenger Pigeons lived at the time. Unfortunately, safety didn’t come in numbers for these denizens of a young, but quickly growing, America.

Few expected the Passenger Pigeon to succumb to loss of habitat and hunting. How could this bird, which flies in enormous flocks that block out the sun, and descends upon crops to devour them like locusts, be so fragile? Thousands of Passenger Pigeons were hunted for food, sport, hog feed, and even fertilizer. Habitat loss was also a key factor in the birds’ extinction. Their forest nesting sites shrank due to the growing lumber industry. The birds would constructed hundreds of nests in a single tree, all of which would be destroyed in one fell swoop of the lumber jack’s ax.

The last Passenger Pigeon was named Martha, and died at the Cincinnati Zoo in 1914.