On About.com, Melissa Mayntz describes that birds have funnel-shaped ears that help them hear and focus sound. Their ears are found slightly behind and below the eyes and are hidden behind soft feathers, called the auriculars, for protection.
Hearing is the second most important sense for birds, Mayntz explains. The shape of a bird's head is one of the factors that affect its ability to hear. For example, owls have facial discs that direct sound toward their ears. Birds have better sound recognition skills than humans, although their frequency range is smaller. They are particularly sensitive to changes in tone, pitch and rhythm. They use such variations to identify other individual birds, even amid a noisy flock. They also rely on varying sounds, calls and songs. They recognize different noises to determine if the noise is a predator's warning, a territorial claim or an offer to share food. Some birds, such as oilbirds, use echolocation like bats do. They use fast chirps and clicks to find their way through dark caves where they live.
Birds have a good sense of hearing, but they tend to hear things differently than people, Earthlife.net explains. While humans perceive sounds through relative pitch, birds recognize sounds through absolute pitch. Furthermore, they recognize "timbre," which means a fundamental note mixed with harmonies.