On April 6, 2010, at 2151 central daylight time, a Beech 95-B55, N70283, sustained substantial damage when it impacted several Mallard ducks during cruise flight at 4,200 feet over Center, North Dakota. Night visual meteorological conditions prevailed at the time of the accident. The flight instructor, seated in the right seat, sustained serious injuries when one duck penetrated the right cockpit windshield and struck his face. The pilot-in-command seated in the left seat was not injured. The flight was being operated by the State of North Dakota Attorney General’s Office as a public-use flight. The instructional flight departed Bismarck Municipal Airport (KBIS), Bismarck, North Dakota, at 2025, and was enroute to Mercer County Regional Airport (KHZE), Hazen, North Dakota. After the bird strike, the pilot-in-command diverted back to the departure airport and made an uneventful landing. At the time of the bird strike, the pilot-in-command was flying while using a view-limiting device to simulate instrument meteorological conditions. He reported that as the airplane was descending through 4,200 feet, he heard a “loud pop” and felt a “violent rush of air”. After the bird strike, there were several large portions of the right windshield missing and the flight instructor was bleeding from his face. The flight crew decided to return to KBIS instead of continuing to KHZE. The PIC declared an emergency with Bismarck approach control and requested that an ambulance meet the airplane after landing. A post-accident inspection revealed that the airplane had received substantial structural damage to the right cockpit windshield, right wing leading edge, and nose cone. All observed damage was consistent with the airplane colliding with several birds during flight.