Why does a rooster crow when the Sun comes up?

A farm rooster is an adult male chicken. Long ago, when chickens had not yet been tamed or domesticated by people and lived in the wild, roosters crowed to call female chickens to mate. This loud crowing caused problems for roosters, though, because it attracted predators as well as female chickens. So to avoid being eaten, roosters began to do most of their crowing when they couldn't be easily seen, like at dawn or at nightfall, when light was dim. Today's roosters continue the habit, crowing mostly in the early morning or early evening. But it is usually most noticeable at dawn because there aren't a lot of other activities and noises to distract your attention.