Read it through once

Now, the first time Ahab was perched aloft; ere he had been there ten minutes; one of those red-billed savage sea-hawks which so often fly incommodiously close round the manned mast-heads of whalemen in these latitudes; one of these birds came wheeling and screaming round his head in a maze of untrackably swift circlings. Then it darted a thousand feet straight up into the air; then spiralized downwards, and went eddying again round his head.