The 12 days of Christmas are indeed all birds, specifically partridges and turtle doves. The partridge in the pear tree is the first day, the two turtle doves are the second day, the three French hens are the third day, the four calling birds are the fourth day, the five golden rings are the fifth day, the six geese a-laying are the sixth day, the seven swans a-swimming are the seventh day, the eight maids a-milking are the eighth day, the nine ladies dancing are the ninth day, the ten lords a-leaping are the tenth day, the