可以考虑译为 mother dog, mother hen,mother bird 等。如：

The young birds were under the mother bird’s wing. 小鸟躲在鸟妈妈的翅膀下。

The mother dog accidentally smothered one of the pups. 狗妈妈不小心把一只小狗闷死了。

Look how the mother chimpanzee cares for her young. 瞧，母黑猩猩（黑猩猩妈妈）多爱护小仔儿啊。

Zoo officials are concerned about the mother elephant. 动物园的官居员们为这头大象妈妈（即母象）感到担忧。