Odd duck

"Theodora is a perfectly normal duck. She may swim with a teacup balanced on her head and stay north when the rest of the ducks fly south for the winter, but there's nothing so odd about that. Chad, on the other hand, is one strange bird. Theodora quite likes him, but she can't overlook his odd habits. It's a good thing Chad has a normal friend like Theodora to set a good example for him. But who exactly is the odd duck here? Theodora may not like the answer"--Book jacket.

Theodora is a normal duck and follows her daily habits. Chad is a bit of a strange egg, chaotic and creative. Which of them is really the odd duck?