The color Blue is also used as "Bluie" to describe a red haired person on a sports team in Australia. The general rule for organizing a team is that you need at least one "Bluie" since they are presumed to be more reckless and crazier than aother members.
How interesting. Have you any idea how the term "bluie" came to designated a red-haired person?
'bluey' is also the term used for a bushman's bundle, the outside cover of which is often blue. other than that, I understood it was typical Strine foolishness.
-joe (Bruce) friday
Maybe it's one of those things like when you call a small guy "moose" or a huge guy "tiny"
More info. here, including a couple of reliable sources:
bluey
I always assumed that it was due to the bluish cast of skin that some non-tanning type redheads have. No idea why tho'