The British have some wonderful Christmas customs that have survived the incursion of Christianity, especially the Puritan party poopers. Stealing customs from the Celts, Germans, and Scandinavians, they have created a wonderful holiday that I fondly remember from time spent there.
The bird is a European robin that is featured on British Christmas cards, as it is a Winter bird in England, unlike the fair-weather laggard of the same name in America.
If you read the Harry Potter
books you will get a taste, but not the full effect of a British Christmas. A full-on Christmas dinner is wretched excess to the n-th degree - Thanksgiving on steroids.