Then there's the flightless rail, whose bones were abundant in the prehuman sands of Ground Dove Cave. They were tame and easy to hunt. Eua dominated the toll of birds lost throughout the South Pacific, Steadman says. Based on his archaeological work, the biologist believes that each of the 800 major islands in Oceania had at least one endemic flightless rail, and some had as many as four. The rail family, some 130 living species strong, includes birds variously known as gallinules, moorhens, swamphens, soras, crakes and coots, and they can be found in all but the colder parts of the world.
Most rails can fly, but it seems to be a struggle.
As exasperated sport hunters know, the birds would rather run from danger, and if they do take wing they quickly flop back into the reeds. The paradox is that once rails become airborne on migration or dispersal flights, they fly as well as any other bird. Once they're stuck on an island, evolution takes over. The flightless rails of the Pacific, such as the species on 'Eua, probably evolved from just such an accident. Windblown rails encountered no enemies on Oceania's uninhabited islands, so they had no reason to keep their now superfluous flight muscles.