"Sparrow" tattoos

OK, so this is a going to be a terminological peeve. The above images show: (left) a sparrow, which is a chunky, short-tailed and typically brown garden bird; and (right) a swallow, a streamlined migratory bird, brightly coloured in many species, with a long forked tail. How could anyone confuse them?

And yet, I've noticed lately a highly prevalent misnomer of referring to the trad swallow tattoo design - most commonly based on the red-and-blue North American barn swallow - as a "sparrow tattoo".

Very occasionally it really is a sparrow.  But (judging by a sample) in the vast majority of the 110,000 Google images hits for "sparrow tattoo", the bird depicted is clearly a swallow - the colourful bird with a forked tail - exactly the same as in the 146,000 Google images hits that correctly describe it as a "swallow tattoo".

I can't at this instant fathom the genesis of this. Did it arise merely from the phonetic similarity; or was it helped along by association with Jack Sparrow in Pirates of the Caribbean, who as a mariner has a swallow tattoo (above)?

Addendum: And I quite forgot another piece of terminology in the same territory. A Monroe piercing is a piercing above the left upper lip, named after the location of Marilyn Monroe's facial mole beauty spot. This has led to a back-formation where the "monroe" is used as a term for this part of the face (as evidenced by many references to getting "my monroe pierced"). So far it's much less common for the opposite location, named after Madonna's now-removed mole, to be called the madonna, but it's not unknown: see "my madonna pierced".

- Ray