Experience shows that as birds 'breeding seasons advance, they become less and less likely to react to outside disturbance by abandoning their nests. So Sun waited until the owls' eggs were nearly hatched before setting up his equipment near the nest to photograph and record the adult birds 'nighttime feeding and the owlets' hatching out.
根據經驗，鳥類繁殖越到末期，越不容易因為外界干擾而棄巢，因此接近蛋孵出期間，孫元勳才在鳥巢附近裝上儀器，拍攝、記錄夜間成鳥餵食、孵卵的過程。