The British expedition from Mackinac had been greatly delayed. During the preceding autumn, Robert Dickson, an English fur trader, had been engaged in recruiting a large band of Indians in the neighborhood of Green Bay, and with them intended to occupy Prairie du Chien. But the Indians were evidently afraid to fight the Americans, and delayed Dickson so that the canoes of his party were caught in the ice on Lake Winnebago (December, 1813), and he was obliged to go into winter quarters on Island Park (known to the white pioneers as Garlic Island).
Poor Dickson had a sorry time with his war party. As soon as it was learned that provisions were being freely given out at this island camp, Indians from long distances came to visit him, under pretense of enlisting under the banner of the British chief. Councils innumerable were held, presents and food had to be given the visitors continually, and Dickson was put to sore straits to keep them satisfied. He found it impossible to get sufficient supplies from British headquarters on Mackinac Island, and was being severely criticised by the officers there, for his exorbitant demands upon them. Nevertheless, unless he kept his Indians good-natured, they would promptly desert him. He was, therefore, forced to rely upon the French of Green Bay for what food he needed. This came grudgingly, and at so high prices that Dickson roundly scolded the Green Bay people, and promised to report them for punishment to the British king, for daring to take advantage of his Majesty's necessities.
While Dickson was thus engaged in Lake Winnebago, a British captain was drilling a number of young Frenchmen at Green Bay, and trying to make soldiers of them; at Mackinac, a similar work was being done among the voyageurs by the two leading fur traders of Prairie du Chien, Brisbois and Rolette. On the other hand, at Prairie du Chien, the American Indian agent, Boilvin, was issuing circulars calling on the people to claim American protection before it was too late.
Late in June the leaders of the expedition started from Mackinac, under the command of Major William McKay, and at Green Bay, Lake Winnebago, and Portage picked up various parties of French and Indians. These bands were much reduced from those who had been so liberally maintained during the winter, for most of the Indians were anxious to keep away from the fighting until it should be evident which side would win, and many of the French were of the same mind. By the time Fox River had been ascended by the fleet of canoes, and the descent of the Wisconsin begun, the allied forces consisted of but a hundred twenty whites and four hundred fifty Indians. All of the latter, according to McKay's report, proved "perfectly useless."
On the 17th of July, the British war party landed at Prairie du Chien, to find the Americans, some sixty or seventy strong, protected by a stockade and two blockhouses, on which were mounted six small cannon. In the river, the keel boat contained perhaps seventy-five men and fourteen cannon. The British had, besides their muskets, only a three-pounder, and the situation did not look promising.
Perkins was summoned to surrender, but he declared that he would "defend to the last man." For two days there was a rather lively discharge of firearms on both sides. Apparently, the British were the better gunners; their cannonading soon forced the men on the keel boat to desert their comrades on shore, and McKay then centered his attention on the fort. The Indians were unruly, being principally engaged in plundering the Frenchmen's houses in the village. The British supply of ammunition had quite run out by the evening of the 9th, and McKay was seriously contemplating a retreat, when he was surprised to see a white flag put out by the garrison.
It appears that the stock of food had become exhausted in the fort, and Perkins had formed an exaggerated idea of the strength of the invaders. The British guaranteed that the Americans should march out of Fort Shelby at eight o'clock in the morning of the 20th, with colors flying and with the honors of war, and that the Indians should be prevented from maltreating them. This last agreement McKay found it very difficult to carry out, for the savages wished, as usual, to massacre the prisoners. To the honor of the British, it should be recorded that they exercised great vigilance, and spared neither supplications nor threats, to insure the safety of their prisoners, whom they soon sent down the river to the American post at St. Louis.
When the British flag was run up on the stockade, the name was changed to Fort McKay, in honor of the British leader. During the long autumn and succeeding winter, the British experienced their old difficulties with the Indian allies. The warriors sacked the houses of the French settlers, all over the prairie, and destroyed crops and supplies. Council after council was held at Fort McKay, and large bands of lazy, quarrelsome savages, encamped about the fort, were fed and were loaded with presents; altogether, the occupation of Wisconsin proved an expensive luxury. It was no doubt with some relief that the British garrison at last learned, late in May 1815, of the treaty of peace signed on the previous 24th of December, and made arrangements to withdraw up the Wisconsin and down the Fox, and across the great lake to Mackinac.