Brahmā
Deva who is the creator of the Universe. He is identified as Chaturmukha Brahmā or the one who has four faces.
Haṃsa
Brahmaa’s vaahana – Hamsa symbolizes moksha, the release from the cycle of birth, death, and reincarnation – samsara.

Story
The Story of Brahma and Hamsa
Long ago, there was a beautiful white swan named Hamsa. Hamsa was special because he had a unique ability: he could drink only the milk from a mixture of milk and water, leaving the water behind. This might sound like magic, but it was a special skill given to him by Lord Brahma.
This special ability was not just about milk and water; it had a deeper meaning. The milk symbolized knowledge, and the water symbolized ignorance. Hamsa’s ability showed that he could take in only knowledge and leave behind ignorance.
Lord Brahma, the great creator of the universe, saw this quality in Hamsa and was very impressed. As the creator, Brahma had to know what was true and what was false. He needed to understand the difference between knowledge and ignorance to create a balanced and beautiful world.
Brahma thought, “This quality of separating knowledge from ignorance is exactly what I need in a companion.” So, he made Hamsa his vaahana, his trusted mount. From then on, Hamsa became the loyal companion of Lord Brahma, always by his side, symbolizing wisdom, knowledge, and understanding.
And that is how Hamsa, the wise white swan, became the faithful companion and vaahana of Lord Brahma, reminding everyone of the importance of seeking knowledge and leaving behind ignorance.
Lord Brahma considers this quality of utmost importance as he is the creator and needs this awareness to differentiate gnyana from agnyana. Therefore he made the Hamsa as his vehicle and mount.