Of all the extinct species that have ever lived, the passenger pigeon had the most spectacular demise, plummeting from a population of billions to a population of exactly zero in less than 100 years. The bird, also known as the wild pigeon, was once widely eaten throughout North America.

01 of 10 Passenger Pigeons Used to Flock by the Billions At the start of the 19th century, the passenger pigeon was the most common bird in North America, and possibly the entire world, with a population estimated at five billion or so individuals. However, these birds weren't evenly spread out over the expanse of Mexico, Canada, and the United States; rather, they traversed the continent in enormous flocks that literally blocked out the sun and stretched for dozens (or even hundreds) of miles from end to end.

02 of 10 Nearly Everyone in North America Ate Passenger Pigeons The passenger pigeon figured prominently in the diets of both Native Americans and the European settlers who arrived in North America in the 16th century. Indigenous peoples preferred to target passenger pigeon hatchlings, in moderation, but once immigrants from the Old World arrived, all bets were off: passenger pigeons were hunted by the barrel-load, and were a crucial source of food for inland colonists who might have starved to death otherwise.

03 of 10 Passenger Pigeons Were Hunted with the Aid of 'Stool Pigeons' If you're a fan of crime movies, you may have wondered about the origin of the phrase "stool pigeon." In the past, hunters would tie a captured (and usually blinded) passenger pigeon to a small stool, then drop it onto the ground. Members of the flock overhead would see the "stool pigeon" descending, and interpret this as a signal to land on the ground themselves. They were then easily captured by nets and became "sitting ducks" for well-aimed artillery fire.

04 of 10 Tons of Dead Passenger Pigeons Were Shipped East in Railroad Cars Things really went south for the passenger pigeon when it was tapped as a food source for the increasingly crowded cities of the Eastern seaboard. Hunters in the midwest trapped and shot these birds by the tens of millions, then shipped their piled-up carcasses east via the new network of transcontinental railroads. (Passenger pigeon flocks and nesting grounds were so dense that even an incompetent hunter could kill dozens of birds with a single shotgun blast.)

05 of 10 Passenger Pigeons Laid Their Eggs One at a Time Female passenger pigeons laid only one egg at a time, in closely packed nests atop the dense forests of the northern United States and Canada. In 1871, naturalists estimated that one Wisconsin nesting ground took up almost 1,000 square miles and accommodated well over 100 million birds. Not surprisingly, these breeding grounds were referred to at the time as "cities."

06 of 10 Newly Hatched Passenger Pigeons Were Nourished With 'Crop Milk' Pigeons and doves (and some species of flamingos and penguins) nourish their newborn hatchlings with crop milk, a cheese-like secretion that oozes out of the gullets of both parents. Passenger pigeons fed their young with crop milk for three or four days, and then abandoned their hatchlings a week or so later, at which point the newborn birds had to figure out (on their own) how to leave the nest and scavenge for their own food.

07 of 10 Deforestation and Hunting Doomed the Passenger Pigeon Hunting alone could not have wiped out the passenger pigeon in such a short period of time. Equally (or even more) important was the destruction of North American forests to make room for American settlers bent on Manifest Destiny. Not only did deforestation deprive passenger pigeons of their accustomed nesting grounds, but when these birds ate the crops planted on cleared land, they were often mowed down by angry farmers.

08 of 10 Conservationists Tried to Save the Passenger Pigeon You don't often read about it in popular accounts, but some forward-thinking Americans did try to save the passenger pigeon before it went extinct. The Ohio State Legislature dismissed one such petition in 1857, stating that "the passenger pigeon needs no protection. Wonderfully prolific, having the vast forests of the North as its breeding grounds, traveling hundreds of miles in search of food, it is here today and elsewhere tomorrow, and no ordinary destruction can lessen them."

09 of 10 The Last Passenger Pigeon Died in Captivity in 1914 By the end of the 19th century, there was probably nothing anyone could do to save the passenger pigeon. Only a few thousand birds remained in the wild, and the last few stragglers were kept in zoos and private collections. The last reliable sighting of a wild passenger pigeon was in 1900, in Ohio, and the last specimen in captivity, named Martha, died on September 1, 1914. Today, you can visit a memorial statue at the Cincinnati Zoo.