Swan, the semiaquatic animal of nature.

Swan is also known as Hamsa. It is the long -necked bird with a red beak and a snow-white body. It is capable to fly high. It belongs to the migratory kind of bird. Its famous living place is Manosarobar , a famous big fresh water lake located in Tibet. This lake is the most sacred lake by both the Hindus and Buddhists and is situated against then backdrop of famous Kailash mountain.
According to Buddhists, in one of his previous birth, Buddha was a golden goose i.e. a kind of Swan He was helping a Brahmin  and his family by providing a feather daily. but the Gee Brahmin one day took off all the feathers which turned white and were of no value.
According to Hindus , Swan is the vehicle of Lord Brahma. Some scientists also consider the bird as the incarnation of Kubera, the Lord of wealth. Bannerjee write that later on the Hansa became the vehicle of Goddess Saraswati.Saraswati is the Goddess of learning.
 Anyway the appearance of a white Hansa or evena white bird over the head is considered to be an auspicious sign. When Budha got enlightenment, white birds similar to Hansa flew over him. Similarly when he descended fromTushita heaven or when he crossed the Niranjan river , white birds flew over the head of Buddha.