The pilot reported that during a training flight in visual meteorological conditions at 900 ft mean sea level, an object impacted the left wing of the airplane, which resulted in substantial damage. According to the FAA, there were no reported missing drones in the area at the time of the accident and a review of radar data showed no primary radar targets in the area. The FAA reported significant bird migration activity, which included several large bird species that would have been active in the area at the time of the accident. While there was no evidence of bird remnants or feathers on the wing, the impact area spanned nearly 3 ft with no puncture of the leading-edge skin, consistent with impact with a large bird. The flight instructor reported that there were no mechanical malfunctions or failures with the airplane that would have precluded normal operation.