The Norfolk Islanders used violence to stake their claim on the land, attacking Aboriginal camps at night, slaughtering parents and abducting the orphaned children as their servants. The attacks prompted retaliatory raids on settlers' cattle herds in the southeast. Between 1817 and 1824 the colonial population rose from 2000 to 12,600 and in 1823 alone more than 1000 land grants totalling 175,704ha were made to new settlers; by that year Van Diemen's Land's sheep population had reached 200,000 and the so-called Settled Districts accounted for 30 per cent of the island's total land area.