In 1803 President Thomas Jefferson directed Meriwether Lewis and William Clark to explore the Missouri River in search of a water route to the Pacific Ocean and to document the geography, plants, animals, landforms, inhabitants, and people they encountered. Trained in natural history methods by leading scientists and members of the American Philosophical Society, Lewis and Clark became the first scientists to document the natural history of the American West through careful and accurate observation. With 26 men in the Corps of Discovery, they left Camp River Dubois in Illinois on May 14, 1804, and by September 23, 1806, after almost 8,000 miles and 28 months, they had described 178 plants and 122 animals previously unknown to science. In this stretch of river, William Clark recorded plentiful game, and the expedition noted species including badger, great egret, least tern, and pine snake near DeSoto and Boyer Chute refuges. On July 30, 1804, at Council Bluff camp near present-day Boyer Chute National Wildlife Refuge, the expedition recorded its second badger, probably the first zoological specimen Lewis preserved, which he skinned and stuffed to send to President Jefferson. On the afternoon of August 3, 1804, after council with the Ota and Missouri tribes, the expedition traveled about 5 miles north and camped along the bank near this location, south of present-day Blair, Nebraska, though shifts in the river have left the exact site uncertain between Harrison County, Iowa, and Washington County, Nebraska.