The Muses’ song ends and Calliope ceases playing her lyre. The Muses explain to Minerva that the nymphs had judged the Muses the winner of the sisters’ contest. The sisters had rudely protested the verdict, and so the nymphs had turned them into a chattering band of magpies.
The sisters were sore losers of the contest with the Muses and refused to believe that the Muses were really superior. Now, the Muses prove their superiority with power by transforming the sisters into magpies.