mounted troops raided up the Thames River as far as Moraviantown. These moves discouraged many of the militia from opposing his invasion, but few of the inhabitants of the region actively aided him, even those who had recently moved from the United States. There were several indecisive skirmishes with British outposts along the Canard River. Hull decided that he could not attack the British fort without artillery, which could not be brought forward because the carriages had decayed and needed repair, and fell back. Several of his officers disagreed with this retreat and secretly discussed removing him from command. Hull had been quarreling with his militia colonels since taking over the army, and he felt that he did not have their support in the field or in their councils of war. British moves On 17 July, a mixed force of British regulars, Canadian fur traders, and Indians captured the important trading post of Mackinac Island on Lake Huron from its small American garrison who were not aware that war had been declared. Many of the Indians who had taken part in the attack either remained at Mackinac or returned to their homes, but 100 or more Sioux, Menominee, and Winnebago warriors began moving south from Mackinac to join those already at Amherstburg, while the news induced the previously neutral Wyandots living near Detroit to become increasingly hostile to the Americans. Hull learned of the capture of Mackinac on 3 August, when the paroled American garrison reached Detroit by schooner. He feared that this had "opened the northern hive of Indians" and so abandoned all the Canadian territory that he held. Hull's supply lines ran for along the Detroit River and the shore of Lake Erie, which was dominated by the British armed vessels, making them vulnerable to British and Indian raiders. A raiding party under Tecumseh ambushed and routed an American detachment under Major van Horne on 4 August at the Battle of Brownstown, capturing more of Hull's despatches. Hull sent a larger party under James Miller to clear his lines of communication and escort a supply convoy of 300 head of cattle and 70 pack horses loaded with flour, which was waiting at Frenchtown, Michigan under Major Henry Brush. Miller forced a British and Indian force under Major Adam Muir of the 41st Regiment to retreat some distance at the Battle of Maguaga on 9 August, but the British