The flight departed Brainard-Hartford Airport and was approximately 5 miles to the northeast at 1,800 feet MSL when a large bird was observed on a collision course. The pilot banked left to avoid the bird and continued the climb. As the bird went out of sight, a "loud thump" was heard, and the pilot reported the bird strike to ATC. After returning to the airport, the right wing was inspected and found to have substantial damage. Published airport remarks include the following: "Birds and deer on and in vicinity of the airport."