The island is known for the Neolithic Isbister Chambered Cairn, popularly known as the "Tomb of the Eagles". Discovered by Ronald Simison in 1958 in the south east of the island, 16,000 human bones and 725 bird bones were found at the site, the latter predominantly belonging to the White-tailed Sea Eagle ("Haliaeetus albicilla"). The evidence suggests that the human bodies had been exposed to the elements to remove the flesh before burial. The tomb was in continuous use for a millennium or more.