As wikipedia so wisely says, yodelling sounds best when performed in echoing mountains ranges - and living as I do about a hundred miles from the nearest mountain, I heartily agree.
In case you're lucky enough not to know, yodelling is a sort of howling song where the performer jumps from his chest voice to a falsetto at odd moments.
And, let's face it, most of the moments in yodelling are odd ones.
The peculiar violence of the sound of yodelling must be the reason why yodelling took off as a music hall act in the 1800s, but before that it was used to communicate in the alps over long distances where a face-to-face chat would have involved a lot of climbing up slopes. A similar sort of thing, but with singing mixed in, called laling, is traditional to Norway (also a place with lots of uphill bits) where it has acted as a sort of signal song. Laling is used to call animals and to send messages between settlements - sometimes with words mixed in with the laling, and sometimes without.
The Mbuti of the Congo yodel to call to each other, too, as well as using yodelling in their music (other musical traditions involving yodelling can be found in Persia, Bulgaria, Turkey, Armenia and Afghanistan.)
The common theme with yodelling is that it's more or less an oi, look at me! message - and that the people who do the yodelling are a long way away.
That makes perfect sense to me.
Thing To Try Today If You Can Get Far Enough Away From Everyone Else: yodel. This word comes from the Austro-Bavarian jodeln, to say jo (it's pronounced yo).