It sounds pretty rugged out there.
It must have been a tough place to live but the population at one time was maybe a couple of hundred or more which is a fair number for a small island.
Several migrations and a few diseases for which they had no immunity had reduced the number to around 28 when they finally left for the mainland.
Although they grew a few vegetable crops and had sheep and small cattle their diet consisted largely of birds and eggs of which the island had a lot.
It is now deserted except for a small military outpost.