Flightless birds in a crisis?!
The Okinawa Rail is a flightless bird that only lives on the main island of Okinawa. Originally in Okinawa, there were few meat-eating animals that could be the only natural enemy to the Okinawa Rail. It is believed that the Okinawa Rail evolved to be an earthbound bird because there was no need for them to fly for escaping. But once people brought mongooses and cats onto the island, the Okinawa Rail soon became in great danger. Because the Okinawa Rail is flightless, so it's very easy to capture them.

Conservation actions at a standstill...
The Okinawa Rail is in great danger of disappearing for other reasons: forests clearing and traffic accidents. But the conservation activities have not progressed much. One reason is that nobody really understands how the Okinawa Rail lives. Without knowing well about the creature, like where the Okinawa Rail lives, what it eats, or how it raises its children, and how far it travels, people cannot move forward with the conservation activities.
Besides the Okinawa Rail, there are many other kinds of flightless birds that are suffering from the outside animals in which human have brought in.