A Crane is a Crane and a Swan is a Swan

In India, a swan's ability to tell itself apart from a goose is described in a Sanskrit poem, metaphor, or proverb. The swan and the goose are both white, according to the proverb. What sets a swan apart from a goose or a crane?
The proof test is to place a bowl of milk mixed with water in front of both of them, and you will find a swan separate from a goose. The proverb says the swan drinks only the milk when the water is separated, and a crane cannot. The London expression "black swan theory," from the old world presumption that all swans were white, prevailed until the discovery of Australia.

In the fictional search for the swan-like character known as Hamsa from Indian classical literature, the author discovers that geese serve as metaphors for a swan for him and denies the existence of wild swans in India.