The bird that lays the cosmic eggs in the standard Kalevala is the goldeneye. In the opening canto, the bird Sotka searches the empty sea for a place to nest and mistakes the raised knee of Ilmatar, the Water-mother, for a grassy hill.
Sotka lays seven eggs there: six golden eggs and one iron egg. After three days of incubation, Ilmatar’s knee becomes unbearably hot. She moves her leg, sending the eggs tumbling into the sea, where they break apart.
Their fragments form the structure of the universe. The lower shell becomes the earth, the upper shell becomes the sky, the yolk becomes the sun, the white becomes the moon, and the mottled and dark parts become stars and clouds.
The bird’s identity is a common source of confusion. The Finnish word Sotka has been translated as goldeneye, teal, duck, or pochard in different editions and traditions. The earlier Old Kalevala also used a different bird in its creation episode, but Goldeneye is the standard answer for the 1849 version.