Why is it unlucky to see one magpie?

Seeing one magpie is considered unlucky in various cultures, particularly in British folklore, where it is often associated with superstition. This belief may stem from the idea that magpies are social birds that typically appear in pairs; thus, spotting a lone magpie is thought to bring bad luck or misfortune. The phrase "One for sorrow" is commonly recited to reflect this superstition, which suggests that the presence of a single magpie heralds sadness or loss. To counteract the bad luck, people often engage in rituals, such as greeting the bird or saluting it.