This episode also reveals much about how waterfowl were hunted during the expedition. Most of the time, members of the Corps shot game that was readily available or would yield the most meat. But when bison or other big game was absent, the explorers sought waterfowl, upland birds, and other small game.

Throughout the expedition, the Corps' hunters used flintlock rifles. But hunting waterfowl with a rifle was not an economical way to harvest birds. Although the party contained several top marksmen, powder and lead were so vital to their survival that conserving these commodities was a priority. As they passed west of what is now Bozeman, Montana, on July 25, 1805, Lewis had to curb his men's enthusiasm for shooting geese: “We killed a couple of young gees which are very abundant and fine; but as they are but small game to subsist a party on of our strength I have forbid the men shooting at them as it waists a considerably quantity of amunition and delays our progress.”

In a broader context, both captains viewed waterfowl as more than merely a source of food. While the Corps' primary objectives were commercial and political, Jefferson also charged its leaders to take note of any new plant and animal species they should come across on their journey. In his journals, Lewis was meticulous in reporting the appearance of every new duck or goose—noting the coloration of its head, neck, wings, breast, and feet; the number of tail feathers; wing and bill lengths; and all other features relative to those of familiar eastern species. For example, he compared the snow goose to the Canada and commented that he preferred the taste of the “white brant” to that of its eastern counterpart. The white-fronted goose, tundra (whistling) swan, and northern shoveler were also among birds new to these men, and in 1806, near today's Rainier, Oregon, Lewis “discovered” the ring-necked duck, which was previously unknown to science.

The journals also recorded the migration patterns of waterfowl. On the shores of the Pacific Ocean, Lewis and Clark observed waterfowl flight patterns during their three-and-a-half-month stay at Fort Clatsop. As the winter passed, they kept record as the birds migrated south and back north along the coast. On November 30, 1805, there was “a great abundance of fowls.” By January 31, 1806, “the Swan white Brant geese & ducks still continue with us,” while “the brown or speckled brant are mostly gone.” And on March 24, the second day of their trip back up the Columbia, Lewis noted, “we saw very few waterfowl today, not a single swan, white brant nor a small goose is to be seen.”

However, the Corps did continue to see and hunt waterfowl as they moved east toward the completion of their mission. Like the early colonists, the Corps of Discovery helped transform the wild America they knew into a modern landscape partially tamed by agriculture and a rapidly growing human population. Alterations to the landscape as well as advances in technology changed the practice and significance of waterfowl hunting in this country. Yet, regardless of how the sport has evolved through the years, waterfowling has remained a North American institution. After all, it's been with us every step of the way.