moult

v.脱毛；换羽毛；脱皮

n.脱毛；脱皮；换羽

=molt(美).

Mature Christmas Island red crabs probably moult only once a year, as their growth rate slows. 成年圣诞岛红蟹或许一年只蜕一次壳，因为它们生长缓慢。

As regards moult, I think it is very useful for adult Heuglin's Gull. 至于换羽，我认为那是辨识灰林银鸥成鸟很有用的特徵。