The idea for this famous story came to du Maurier one day when she was walking across to Menabilly Barton farm from the house. She saw a farmer busily ploughing a field whilst above him the seagulls were diving and wheeling. She developed an idea about the birds becoming hostile and attacking him. In her story, the birds become hostile after a harsh winter with little food - first the seagulls, then birds of prey, and finally even small birds - all turn against mankind. The nightmarish vision appealed to Hitchcock who turned it into the celebrated film.