12 days of Christmas: Four calling collies

On the fourth day of Christmas, my true love gave to me… four colly birds? Calling birds? Which is it?

Modern audiences will typically sing calling birds, but the original was colly birds, and it turns out there are scientific explanations behind lyric transformations of this kind – known as mondegreens.

What are mondegreens?

Mondegreens are incorrect words or phrases arising from the mishearing of lyrics in popular songs. The term was coined from a 1954 essay by Silvia Wright, in which she remembered how as a child, she misheard the start of one of her favourite poems, The Bonnie Earl O’Moray: “They hae slain the Earl o’ Moray, And Lady Mondegreen”

The line was in fact, “And laid him on the green,” and the incorrect word – which Wright quipped was better than the original, was used to name the phenomenon.

Why do we mishear lyrics?

Sound is made up of pressure waves travelling through the air. When it reaches our ear canal, the ear drum vibrates, and a few small bones amplify this vibration, passing it through towards the cochlea.

The cochlea is a spiral-shaped component covered in thousands of tiny hairs, which convert the vibration into an electrical signal, which is then interpreted by the brain.

The way the brain interprets the signal is hugely complex, which is why the perception of sound varies so dramatically from person to person. Add in layers of confusion introduced by music, such as instruments that might muffle the vocal line, and it’s hardly surprising that so many people mishear lyrics from popular songs.

Psychological research suggests that we are likely to substitute a phrase we don’t hear clearly with one which makes more sense to us. In addition, it’s harder to hear the correct lyrics when the brain has formed a version they now expect to hear.

Sound and hearing are hugely subjective, as is our enjoyment of lyrics and poetry. The poor colly birds may therefore have to resign themselves to being left out of the 12 days of Christmas, at least for now.