The To’aga site on Ofu spans virtually an entire three-millennium-long sequence of Samoan archeology, and is exceptionally rich in the period from about 3200 to 1900 years before the present. A very significant study (The To’aga Site, edited by P.V. Kirch and T.L. Hunt) was funded by the Samoa Historic Preservation Office with grants from the National Park Service.

The deeply stratified site contained a long and continuous sequence of ceramics that dating to more than 3000 years before the present time. Similar to island sites throughout the Pacific, archeologists found that early peoples on Ofu did modify the landscape and biota. Among their discoveries were earliest strata containing middens with bird bones of five species of petrels or shearwaters and a megapode, none of which now occur on Ofu. On Ofu not a single species of petrel or shearwater (a highly exploited human food) has survived the three millennial of human occupation.  Ofu is typical of the other Pacific islands where, with very few exceptions, earliest human occupants eliminated or drastically depleted the original dense populations of shearwaters and petrels. 

Species found earlier on Ofu, but now eliminated, included the megapode (Megapodius sp.); wedge-tailed, Audubon's, and sooty shearwaters; Tahiti and another unidentified petrel; and red-footed booby.

Archeologists (like those who authored The To’aga Site report) are scientists who probe the past based upon physical evidence they find on or in the ground.  In contrast, anthropologists document the past by studying people and their cultures, including recording their oral histories.  Often these two sciences corroborate each other.  Today the To’aga site is no longer occupied, but anthropologists record persisting local legends that aitu, ghosts of their ancestors, still haunt the ancient To’aga site.