We'll answer a listener's question about birds' sense of smell. Helen, most birds don't have a sense of smell. It's possible that a sense of smell withered away in birds because of the demands of flight. The process of natural selection might've favored birds with lighter brains for better aerodynamics. For most birds, vision and hearing are the most important senses.
Birds have sharp eyesight, and their eyes can dart quickly to spot food or predators.
And since birds sing, they need keen hearing to detect the subtleties of songs and calls. But although most birds lack a sense of smell, there are some exceptions. For example, carrion-eaters like the Turkey Vulture sniff around for their supper. And there's some evidence that certain seabirds can smell their colonies and may follow their beaks to find their breeding islands. This rumor was probably started by well-meaning parents.