Spring 1831
Black Hawk ordered the whites away, threw down their fences, unroofed their houses, cut up their grain, drove off and killed their cattle, and threatened the people with death if they did not leave; he ordered the settlers to leave the locality or be removed by force.
The evidence
“Believing that the treaty was void, 'Black Hawk resisted the order of the government, for the removal of his tribe across and west of the Mississippi, though compelled to comply. In _ the spring of 1831 he recrosed the river with his women and children, and three hundred warriors of his own tribe, together with some allies from the Potawattamies and Kickapoos, and established himself in his ancient hunting grounds. He ordered the whites away, threw down their fences, unroofed their houses, cut up their grain, drove off and killed their cattle, and threatened the people with death if they did not leave.”
1856-history-of-rock-county/02-black-hawk-war.md, PDF p. 32 / book p. 14
Guernsey, Orrin, and Josiah F. Willard, editors. History of Rock County, and Transactions of the Rock County Agricultural Society and Mechanics' Institute. Janesville, Wis.: William M. Doty & Brother, 1856. Cornell University Library via the Internet Archive, archive.org/details/cu31924028871593.
Grade A: Found on a page of one of our sources
“This placed them technically in the right. So when Black Hawk returned to the village in the spring of 1831, after another unsuccessful hunting season and ordered the settlers to leave that locality or he would remove them by -force, they confidently appealed to the governor of Illinois, John Reynolds, for protection. In his biography, written at his dictation in after life by Editor Patterson, Black Hawk claimed that he did not mean bloodshed or war, but simply the use of physical force.”
1908-brown-rock-county/03-black-hawk-war.md, Vol. 1, PDF p. 45 / book p. 36
Brown, William Fiske, editor. Rock County, Wisconsin: A New History of Its Cities, Villages, Towns, Citizens and Varied Interests, from the Earliest Times, Up to Date. Chicago: C. F. Cooper & Co., 1908. 2 vols. archive.org/details/rockcountywiscon01brow, archive.org/details/rockcountywiscon02brow.
Grade A: Found on a page of one of our sources