Hraesvelg

Then spoke Gangleri: ‘Where does the wind come from? It is so
strong it stirs great seas and whips up fire, but strong as it is, it
cannot be seen. Thus it is marvellously made.’

Then said High: ‘I can easily tell you that. At the northernmost
end of heaven there sits a giant called Hraesvelg. He has eagle
form. And when he starts to fly winds arise from beneath his
wings. It says so here:

He is called Hræsvelg who sits at heaven’s end, giant in
eagle form. From his wings they say wind comes over all
men.’

Then spoke Gangleri: ‘Why is there such a great difference
between the warmth of summer and the cold of winter?’


- Prose Edda, Gylfaginning