so that's why!

we've visited Barcelona twice over the Christmas/New Year celebrations and have been puzzled by the little figures having a poo which are placed at the side of the Nativity. We've tried for years to find out what they are and why they are so carefully placed on the edge of the Nativity, with no success so far.
But now I know!

They are called caganers which is Catalan for *ahem* shitters (sorry, some sources cite it as "fertilizers") and are to bring good luck and a prosperous harvest next year,
or they might be to symbolise Christ's humanity,
or they might represent all mankind, in that Jesus is for everyone,
or they might represent the fact that God will manifest Himself when he is ready, whether we are ready or not.

Or, it might just be the Catalan's earthy sense of humour.

Traditionally they would be dressed in traditional Catalan costume, but often now they are famous figures, such as the footballer Lionel Messi as in the photo and have become collectible figures.

I'm not sure if I would want to collect lots of little figures with their pants down, but I'm glad I know what they are now!