The earliest period of Māori settlement is known as the "Archaic", "Moahunter" or "Colonisation" period. The eastern Polynesian ancestors of the Māori arrived in a forested land with abundant birdlife, including several now extinct moa species weighing from 20 to 250 kilograms (40 to 550 lb). Other species, also now extinct, included a swan, a goose and the giant Haast's eagle, which preyed upon the moa. Marine mammals, in particular seals, thronged the coasts, with coastal colonies much further north than today.[20] At the Waitaki river mouth huge numbers of moa bones estimated at 29,000 to 90,000 birds have been located. Further south, at the Shag River mouth at least 6,000 moa were slaughtered over a relatively short period.