Indian tradition gives the swan, or more strictly the hamsa, often a goose rather than the mute swan of Europe, a place of high honour as the mount of Brahma the creator and of Saraswati, goddess of learning and the arts. The hamsa is credited with the ability to separate milk from water when the two are mixed, and this became a standard image for the discriminating wisdom that separates the real from the unreal, the eternal from the transient; the accomplished ascetic is called a paramahamsa, the supreme swan. The bird's whiteness, its grace on the water and its migratory freedom all feed a symbolism of purity and of the soul detached from the world it moves through.
The bird most likely meant by the Sanskrit hamsa, the bar-headed goose, is itself one of the most extraordinary fliers among birds: it migrates twice yearly directly over the Himalayas, flying at altitudes exceeding seven thousand metres where oxygen is a third of sea-level pressure, a physiological feat documented by modern tracking studies that gives an unexpected literal grounding to the hamsa's old reputation as a bird that moves between the earthly and the transcendent. Which real bird the Sanskrit hamsa names is itself debated among scholars: alongside the bar-headed goose already discussed, some argue for the greylag goose or for a partly composite, idealised bird rather than any single species, an ambiguity that has not stopped the word from giving its name to revered teachers, Ramakrishna Paramahamsa among the best known, styled the supreme swan regardless of which bird the term first pictured.