The passenger pigeon was massacred by humans in the 19th century; coupled with deforestation, this led to its extinction in the early 1900's. A flock of passenger pigeons was documented in 1866 as being a mile in width and 300 miles in length — it took about 14 hours to pass and darkened the sky. The largest nesting recorded was 135 million adult birds; the largest flight was estimated to be 2 billion birds. This beautiful pigeon loved to eat acorns, beechnuts, and chestnuts. A keystone species, its vast quantities of droppings and limb-breaking nesting habits enriched the soil and helped shape the ecology of North American forests. Illustration below, "Fall of the Passenger Pigeon," was drawn in pencil, colored in Photoshop in 2019.