Why do peacocks screech?

Peacocks don't screech, they call. The call of a peacock is often referred to as a "screech" because it is a loud, high-pitched sound. However, the term "screech" is not entirely accurate, as the call of a peacock is more of a harsh, raucous sound. The call of a peacock is usually made by the male bird, and is used to attract females and defend their territory.