Kwankwanxwalige', a supernatural Ancestor of the Kwakwaka'wakw, bestowed many supernatural gifts upon his human descendants, thus, many stories relate to his adventures and powers. Thunderbird lives in a great house in the sky (Thunder-Bird-Place) with his wife, four children and his younger brother and attendants. There, he is Chief of the sky birds or beings and is the only one who owns a salmon trap. He is capable of sending forth windstorms, lightning and other bad weather. Flapping of Thunderbird's wings can cause thunder and it is said that lightning flashes from his eyes.

When a supernatural ancestor of 'Namgis, 'Namxxelagiyu was having trouble lifting some heavy house beams, a thunderbird flew down from the sky and helped him by lifting the beams in his talons and putting them into place. Then the thunderbird assumed human form by removing his bird skin and throwing it into the air. As it flew away, he said, "You will only cause thunder and lightning when one of the people in this place dies." And thus, thunder can be an omen of death.

After Thunderbird captured the wife of the Chief of the myth people who lived at Crooked Beach on Kalugwis or Turnour Island, a great war ensued in which four of the Thunderbird's children were killed. Only a young boy of nine months survived. Thunderbird took off his adornments and placed them upon the child. He then commanded that future generations would do the same with their children so that they would be kept well. The noise of thunder would only be heard when he moves from the summer side to the winter side of his house.

According to the Kwikwasu'tinux tradition of Gwa'yasdam or Gilford Island, Thunderbird was called Too-Large while living in the Upper World with his wife. Donning their masks, the two of them flew to the lower world where a man named Only-One-on-the-Beach, asked if the Thunderbirds would change into men and help construct his house.

The name of Too-Large became Head-Winter-Dancer and his wife became Winter-Dance-Woman. They built their house on a hill and from them came a large tribe and much greatness.

In addition to whales, the food of the thunderbird is the double-headed serpent or Sisiyut‡, both of which are his salmon. At one point in the story of the Head-Winter-Dancer, he gives the blanket of wormwood to a man named Food-Giver so that he may have the supernatural power of lightning. There is a large stone located on Sandy Beach at Gwa'yi (Kingcome) the home of the Dzawda'enux. This stone is a Thunderbird that tried to catch a double-headed serpent.

This mask has an articulated lower jaw, disproportionate "horns" of metal painted red, and a metal disc nailed on for each pupil (painted black).

Thunderbird song of Chris Cook II, 'Namgis
You are always soaring around this world, you are a supernatural being, with your body trembling with spiritual power; you come from the great story of our beginning, you are spiritual, you are the unequalled thunderbird, wonderful.
You are constantly creating thunder in our world, you are not of this world, causing thunder everywhere, you are the ancestor from the beginning, thunder maker, and you are the powerful thunderbird, amazing.

This mask originally belonged to Harry Mountain. It was surrendered to the Canadian Museum of Civilization and was returned to the U'mista Cultural Centre in 1979.