The pilot of the multiengine airplane reported that, on a descending vector for a visual instrument landing system approach on an instrument flight rules flight plan, about 2,500 to 2,800 ft mean sea level, he "felt the aircraft shudder along with a loud bang." He then disengaged the autopilot to determine if the flight controls were affected and looked for damage on the wing and nose area; he saw no damage. The pilot continued to the airport and landed without further incident. During the landing, the pilot of a waiting aircraft reported that he saw damage to the accident airplane's vertical stabilizer that looked like a bird had hit it. During postaccident examination, blood and tissue were found on the airplane. The airplane sustained substantial damage to the vertical stabilizer. The pilot reported that there were no preaccident mechanical failures or malfunctions with the airplane that would have precluded normal operation.