Love and the Birds: The Origin of St. Valentine's Day

On February 14, Americans celebrate love and friendship by exchanging cards, flowers, and candy. Although the origins of Saint Valentine's Day are murky, the romance we associate with the day may spring from the medieval belief that birds select their mates on February 14.

" For this was on seynt Volantynys day, Whan euery bryd comyth there to chese his make."
[Translation "For this was Saint Valentine's Day, when every bird cometh there to choose his mate."]
from Parlement of Foules (1382) by Geoffrey Chaucer (1340?-1400)

Source: Wikipedia's Saint Valentine's Day