On October 27, 2022, about 1500 eastern daylight time, a Robinson R44, N442H, was substantially damaged when it was involved in an accident near Sarasota, Florida. The flight instructor and passenger were seriously injured. The helicopter was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. According to the pilot, while en route, he saw birds in his flight path, he banked to the right to avoid striking one, and then he felt a vibration in the helicopter. He moved the collective up and down in an attempt to stop the vibration; however, it continued. The pilot performed a precautionary landing to a marshy area, and the helocopter subsequently rolled over, resulting in substantial damage to the fuselage. Examination of the helicopter by a Federal Aviation Administration inspector revealed that the tail rotor exhibited a dent. The inspector and a mechanic examined the helicopter for any anomalies and noted that there were no mechanical malfunctions that would have precluded normal operation. The dent was examined for evidence of a bird strike; however, the dented side of the tail rotor landed in the marsh water and remained there until it was recovered, and no evidence of organic material was noted.