What do you mean by rare birds and animals?

What do you mean by rare birds and animals?

Rare Birds and Animals _ Interpretation of Idioms

Pinyin: zhēn Qin yòshòu

Interpretation: Jane: precious; Odd number: special. Rare birds and animals.

Source: Shangshu Lu Mastiff: "Dogs and horses are not native animals, rare birds and animals, and China is infertile."