This jig is in 6/8, compound time; the majority of Scottish jigs are in this time signature.
This tune started out life as a 6/8 march but over the years it has gathered speed, the quavers have become more even and it is now played by most as a jig, although it can still be heard played as a march.
Note the unisons in the first part of the tune; these are an important stylistic feature in Scottish fiddle playing. To play the unison on any stringed instrument play an open string (in this tune it is E) along with the same note on the string below. On the fiddle you would play your 4th finger on the A string along with the open E string to create the desired effect.
Listen to a recording of The Athole Highlanders.