Frozen sperm enables embryo development in endangered Japanese bird for first time—but chick fails to hatch

The Okinawa rail (Hypotaenidia okinawae) is an endangered flightless bird endemic to the Yanbaru forest region of Okinawa Island in Japan. The bird has only recently begun recovering its numbers after introduced predators, such as the mongoose, and traffic accidents reduced its population to as low as 820 individuals.