He calls his magic art to aid With wind and cloud and gloomy shade. When in the fight my power was spent My wearied wings he cleft and rent. Then round the dame his arms he threw, And to the southern region flew.

In plain words: Jatayu says Ravana used magic to create wind, clouds and darkness. When Jatayu grew tired, Ravana cut his wings, grabbed Sita, and flew south.