Even today, many years later, Liang clearly remembers the bright, blood-red color. In fact, most bird species have red mouths when young. When they sit in the nest with their greedy beaks wide open, the bright red gives their mothers an easy target when returning to drop food into their gullets.
其實大半幼鳥都是「紅口」小兒，蹲在巢中張大口嗷嗷待哺，離巢覓食的母親回巢後，一眼瞧見血盆大口貪嘴的小鳥，目標明顯，拋下食物，正中「紅心」，減少誤投。