While looking online for the meaning of the cardinal's name, I found that some people believe these beautiful red birds are messengers -- that their name is from the Latin cardo, meaning an axis or a hinge and that the cardinal is the hinge on the gate between Earth and the spirit realm and the carrier of messages between the two.
I also found that some Christians see the cardinal as a symbol of Christ's blood and of Christmas. And some Native Americans regard them as lucky, believing that the person who sights a cardinal will receive good fortune in twelve days time. As we see cardinals daily and year round, the Native American belief is my favorite.