Updated: Nov 15, 2020
Nīrakṣīra viveka nyāyaḥ (discerning milk mixed with water)
A swan has a God-given ability to extract and drink just milk from the mixture of milk and water.
This instruction is of great practical moral and spiritual value. On a materialistic level, this is a way how to be not morose, but happy, and liked. Nīti-darpaṇa 1.16 states:
viṣād apy amṛtaṁ grāhyam amedhyād api kāñcanam nīcād apy uttamāṁ vidyāṁ strī-ratnaṁ duṣkulād api
"A wise man will extract nectar from the pot of poison, takes a piece of gold from a filthy place, accepts high advice even from a low man, and accepts chaste wife even from unworthy family." Such a moral man is looking for that what has some value