The St Kildans relied on crofting and fishing to survive. Up until the mid-1800s they were totally self-sufficient with little contact from the mainland or other islands. One of the food sources that they relied upon were the seabirds that inhabited the cliffs and the men would abseil down to the nests to harvest live birds (gannets, fulmers and puffins) and their eggs.
However, by the late 1800s, things began to change. The loss of self-sufficiency and reliance on imports such as food and fuel meant that they were no longer able to survive without external contact. During bad weather there were severe food shortages as deliveries could not be made and this led to famine and illness. The outbreak of World War 1 brought a naval detachment to the main island of Hirta, which enabled extra deliveries and more contact with the outside world. When the war ended and the naval base was shut down, a feeling of growing isolation was felt among the islanders. Eventually, it became too unmanageable and the remaining 36 islanders requested to be evacuated.