Robins have long been associated with the season of, well, er,
No, really. The red breast is supposed to have been caused when a robin was stained by Christ's blood when it sat on His shoulder ease His pain by singing to Him.
In fact robins have long had a taste for high company: they used to be associated with the god Thor, too. I must say, though, that nowadays they're not so fussy: we have our own robin in the garden which sings to us and dances round our feet whenever we start digging.
Our robin is a European robin, but there are redbreasted birds called robins all over the world. For instance, there's the American robin, Turdus migratorius:
which is a bit bigger than my robin; and there are Australian scarlet robins:
So why are robins all over Christmas cards?
Well, it seems to be because in the 1800s in England the postmen wore red waistcoats. This gave the postmen the nickname Robin - and because then, as now, Christmas brought with it a lot of post there began to be a natural association of robins with Christmas.
My own robin keeps his bright black eyes on me as he hops round my feet (though he may be a she, it's not possible to tell) and those lovely robin eyes are extraordinary - or, at least, one of them is, because one of a robin's eyes can see the magnetic field of the earth. It helps them migrate - though my own English robin is too stuffed full to bother about migrating.
Spot the frippet: robin. This bird was first called the redbreast, but a fashion in the 1500s for giving things the names of people led to Robin Redbreast, and hence to Robin.
If you don't have a local version of a robin then there's always Batman's friend, isn't there.