Role in Myths
The information about this Jötunn is very scarce, as he was only mentioned in stanza 37 of the poem Vafþrúðnismál from the Poetic Edda. Hræsvelgr is said to sit at the end of the world (or the northern edge of the heavens) and causes the wind to blow whenever he beats his wings in flight. This is repeated by Snorri in the Gylfaginning section of his Prose Edda.
Hræsvelgr is at times confused with the giant eagle who has a rivalry with the serpentine dragon Nidhogg and a hawk on its head that called Vedrvolnir, but it must be noted that he and the eagle are separate beings.
Because of limited information, not much is known about Hræsvelgr but, being a Jötunn, it's highly likely that he has inherent bigotry against the Gods, particularly Gods of Asgard.
Powers and Abilities
In addition of possessing qualities of a bird of prey (albeit on a massive scale), Hræsvelgr can release powerful gusts of wind with flaps of its wings alone.