What are the five species of mouse on the Faroe Islands...?

Question

That mutated after originally being from just one species, the house mouse.

Answer 1

The Faroe Island mice populations are not usually considered full separate species, but usually designated as subspecies of the Western European house mouse (Mus domesticus).  There is the Nolsoy house mouse (Mus domesticus faroeensis), the Mykines house mouse (Mus domesticus mykinessiensis), and the now extinct St Kilda house mouse (Mus domesticus muralis).

There were also records from the 17th century of the wood mouse (Apodemus sylvaticus), but these have not been seen since and may have been a misidentification.