The pilot stated that he had the airport in sight, and was at 2,000 feet, descending to land, when he heard a loud noise, and felt the airplane shudder. He said that the aircraft controls were not affected, so he continued the descent, and made an uneventful landing. After securing the aircraft, the pilot noted that a large turkey buzzard had impacted the vertical stabilizer. A licensed aviation mechanic who examined the aircraft stated that the vertical spar had been bent as a result of the impact.