When Polynesians colonized the Hawaiian Islands between AD 400 and 600 they should have filed an environmental impact statement. A study of fossil bird bones shows that the colonizers decimated the islands' fauna.
This undercuts the long-standing assumption that prehistoric and presumably ''primitive'' islanders lived in harmony with their environment - a harmony that European settlers disrupted.
Storrs L. Olson and Helen F. James of the Smithsonian Institution have studied tens of thousands of fossil bird bones over the past decade on five of the main islands. They find that at least 39 endemic species of land birds and one species of sea bird had become extinct before Europeans arrived. Of these birds, only three had previously been named.
Reporting this in the journal Science, James and Olson point out that ecologists have been deceiving themselves when they have taken the early records of European naturalists as typifying the native island flora and fauna. On the contrary, they say that ''the Polynesian residents may have been responsible for the disappearance of more than half the endemic avifauna of the Hawaiian Islands.''
This is not to say that the impact of Western settlement has been any less devastating. Indeed, the rate of species extinction among island populations has accelerated in historic times. It now is one of the world's leading conservation problems. But, the Smithsonian scientists conclude, ''The assumption that the historically known biota of a prehistorically inhabited island contains an intact complement of species in a natural state of equilibrium is invalid for the Hawaiian Islands, and is most likely invalid for other islands as well.''
James and Olson suggest the ancient extinctions were due to a combination of habitat destruction and predation. They point out that dogs, pigs, and rats, which came along with the humans, would have been hard on flightless birds as well as on those that burrow or nest on the ground.
Besides total extinction of many species, the range of species that survived was often greatly reduced. Since James and Olson are studying bird fossils, they did not report on other animals. But it seems likely that more than birds suffered from the invaders. The two scientists do point out that the drier lowlands on the islands once were forested and supported many plant species. Of these, only scattered remnants remain. Such forests may have been burned off to provide farmland.
As has happened in some other instances, this research shows the myth of ecologically minded primitive peoples living at one with nature to be an empty romanticism. Instead, the legacy of these peoples in Hawaii is that of an impoverished environment. It stands as a warning to our own age to take better care of the world's islands.
It also should force ecologists to rethink their theories of island life. The records that underpin some of that theorizing do not appear to represent the undisturbed state of nature that has been assumed.