The American Kestrel named Huckleberry is owned by Caleb Summers, son of Hermes.
Hermes gifted it to Caleb, although he doesn't know it yet. Hermes set it free in a forest in which Caleb would eventually walk through to get to camp. He instructed the Kestrel to wait until Caleb got there and then follow him and befriend/protect him. Huckleberry also has an empathy link with Caleb. The falcon normally is with Caleb.