Chupacabra's Song — Jim C. Hines

In the Magic ex Libris series, Nicola Pallas is one of the most powerful magic-users in the world, able to overpower her enemies with little more than a whistle. She's also known for raising chupacabras in her barn.

This 5000-word short story introduces Nicola as a young girl, new to magic and unfamiliar with her potential. A woman brings a strange creature to Nicola's father, the local veterinarian. That injured animal--Nicola's first encounter with a chupacabra--leads her into a larger world of magical poachers, supernatural creatures, and danger.

It also offers the possibility of a life-changing friendship. Assuming Nicola survives.

The story is set approximately twenty years before the events of Libriomancer.