In addition, many diurnal birds of prey have proportionately more sensory cells in the upper half of the retina. This helps a bird perceive images when looking toward the ground from a perch or when flying. As a consequence, to scan the sky, they must turn their heads upside down. Diurnal birds of prey are thought to see objects at a distance about the same as or up to three times better than humans. Diurnal birds of prey see color, which may play an important role in food identification and reproductive behavior.
Birds have an acute sense of taste.
Taste is used to help avoid harmful foods. Sensitivity to each of these tastes differs from species to species. The importance of smell differs from species to species. Most diurnal birds of prey aren't sensitive to smell. Scientists feel that birds possess a sense of touch much like humans.