Once numbering as many as 5 billion across much of the United States and parts of Canada, the last passenger pigeon died in captivity on 1 September 1914.
By as early as 1856, some naturalists had warned that the excessive hunting of the bird would lead to its extinction. Bills to protect the bird were defeated in Michigan, Ohio, and Pennsylvania, and arguments that the bird was in danger were widely dismissed. By 1890, the passenger pigeon was noticeably depleted, and the last bird in the wild was shot less than a decade later.
The Cincinnati Zoo (one of the oldest zoos in the United States) kept passenger pigeons from its beginning in 1875. In 1909, a female named Martha, and 2 males were determined to be the only living passenger pigeons in existence. After the males died without producing offspring, a reward was offered for a male. None were found. When Martha died she was around 29-years-old.

