But demand for nests has continued to rise, and the price went from M $ 140 per kilo in 1987 to M $ 4000 in 1991, leading to constant illegal scavenging. Since efforts to protect the birds had little effect, the only thing was to lift the ban after three years.
但燕窩需求有增無減，價格更由一九八七年的每公斤一百四十馬幣漲至一九九一年的四千馬幣，使得禁採地區不斷遭到盜獵，護燕成效不佳，三年後，只好又開放採收。