The passenger pigeon's extinction was shockingly rapid. In the early 1800s, they were arguably the most numerous bird on Earth, with flocks so dense they could darken the sky for days. Relentless commercial hunting for cheap meat, coupled with deforestation, decimated the population. By the 1890s, they had virtually vanished from the wild. Martha, hatched in captivity and named after Martha Washington, spent her final years as a zoo attraction. After her death at age 29, her body was frozen in a