One of the reasons forestry authorities have had such poor results exterminating field mice, squirrels, and other pests despite spending so much money each year is the reduction in numbers of birds of prey, the pests 'natural enemies, which has allowed them to increase to harmful proportions.
台灣省農林廳與林務局，每年花在農地野鼠及危害森林松鼠等小動物防治上的經費不貲，但成效並不顯著。原因之一，就是失去了自然界猛禽類的幫助，使這些鼠類在沒有天敵的威脅下大量繁殖為害。