On the Fourth Day of Christmas...

...My true love gave to me 4 calling/colly birds, 3 french hens, 2 turtle doves, and a partridge in a pear tree.

In the brief research I just did on the fourth day of Christmas, I found out that the "4 calling birds," as I grew up singing, should actually be "4 colly birds," which is a type of black bird.

How did we go from colly birds to calling birds? Well, I don't really know, but one clue I found is in the intent of the song. It is believed that originally the 12 days of Christmas was a secular song that reflected the gifts a young woman was receiving from her true love (she must have loved birds!). Later on it is believed that the song was adapted as a catechism for young Catholics. The purpose of the song was to learn the surface meaning of the song in relation to a deeper religious meaning. I learned this HERE.

The 4 calling birds was adapted from colly birds to represent the 4 gospels of Matthew, Mark, Luke, and John. I'm sure 4 colly birds could represent the 4 gospels just as well as 4 calling birds, so there must be another reason for the change. All the same it's a pretty interesting evolution of the song, I think.