Anyway, it transpires that in Eastern Europe there's a tradition regarding female water-spirits named Rusalka. The name apparently translating, quite literally, as "red-haired girl". This is really fascinating. I was completely unaware of this tradition and it really adds a new dimension to the whole mythology of red hair.
Rusalka is a water nymph, a female spirit in Slavic mythology. Her name comes directly from East Slavic русалка (originally meaning "red-haired girl") and still vernacularly translates as "mermaid" from Belarusian, Russian and Ukrainian (even though in literal sense, this is incorrect). Rusalka also appears in West Slavic folklore under the names rusalka (Czech, Slovak) or rusałka (Polish).The link between "red-haired girl" and "mermaid" is equally fascinating.
The whole Wikipedia article is quite fascinating too (and refreshingly short) for anyone interested.
The water spirits were supposedly the spirits of girls who had drowned, and would lure young men to their deaths. They were apparently at their most dangerous during Rusalka Week (green week). The whole legend seems quite tied up with pagan fertility rites.
This is all also quite interesting to me as I've speculated elsewhere that the name Mary Magdalene can be translated as "mermaid". She, of course, was also supposedly red-haired. Maybe these same rites and myths were once common in other parts of Europe too.
I'm going to write a full article covering this in much more depth at some point, as I feel it's a topic worthy of much more attention. I'll probably put that one on the main website.