Incident Overview
A helicopter operating over open water encountered a large flock of white birds at an altitude of approximately 400 feet above ground level, about half a mile from shore. The pilot reported sighting the flock and attempted to avoid a collision by flaring to a stop, but was unable to prevent impact.
Sequence of Events
After the helicopter struck one or more birds, an extreme vibration developed. In response, the pilot elected to descend and touch down on the water surface. The aircraft touched down on the water, subsequently rolled over, and sank.
Outcome
The pilot was able to egress from the sinking helicopter and swam to shore. The pilot sustained no injuries. The helicopter was not recovered.