In late 1806, Lieutenant Zebulon M. Pike led a U.S. Army expedition to explore the United States' new southwest boundary with New Spain, accompanied by Dr. John H. Robinson, "Baroney" Vasquez, Sgt. William Meek, Corp. Jeremiah Jackson, and Privates John Brown, Jacob Carter, Thomas Dougherty, William Gordon, Hugh Menaugh, Theodore Miller, John Mountjoy, Alexander Roy, Patrick Smith, John Sparks, and Freegift Stout. On December 26th and 27th, 1806, the party marched to the entrance of the mountains through snow, extreme rough roads, and frequent falls by their horses, while some of the men were sick and Pike believed that neither animals nor aborigines ever took that route. In this treacherous stretch, travel demanded movement on the frozen river, packs had to be redistributed, and the men caught and caged a Carolina parakeet, now extinct. At the end of this ill-fated part of the expedition, Pike split up his men to find a way out of the canyon, keep sleds and injured horses moving, and continue hunting. After 6-7 hard days, they reached the area of Cañon City where he had begun his northward search for the headwaters of the Arkansas, and he was surprised to find that he had returned to the same area where he started. Pike's journal also recorded the severe conditions of the journey in November and December 1806, when the prairie lay under stormlike clouds, the thermometer fell to 4° below 0, and the party was 800 miles from the country's frontiers in the most inclement season of the year, with many men lacking winter clothing and blankets. In late November, Lieutenant Facundo Melgares and his Spanish troops, having shadowed Pike's expedition, headed south for Santa Fe.