Long Held Understandings Overturned (in Christmas Music)

Christmas songs. Every year at malls and restaurants and other spots the ubiquitous Christmas music and Christmas songs seem to be everywhere. They're public domain, so anybody can sing them and anybody can record albums of them; that seems to be why there's so many.

And, up until last night, December 17th of 2012, I had an incorrect understanding of a lyric of "The Twelve Days of Christmas". For my entire life I thought a lyric was one thing, only to learn it was not.

See, a comic strip in the paper is doing a pun-heavy parody of The Twelve Days, and one of their drawings I had no idea what it was punning. So I looked it up, and remembered. 

Then I noticed something. On the fourth day the true love gave "four collie birds". What? Four collie birds? Is this new to anyone else? And what's a collie bird? I looked it up: a "collie" bird, or "colly" bird, is a regular common European blackbird. That changed my whole concept of the song.

I'd been under the impression for my entire life up until last night was that the lyric was "four calling birds". I guess I'd always figured they were myna birds or some other mimic. Am I the only one there?