That one actually *isn't* modal in the original sense of the word - the mode system was developed for categorizing chant melodies, and that tune doesn't have a reciting tone (modal dominant).

"The Burning of Auchindoun" (in my modes tutorial) is closer to the original chant model, as the tune hovers around on the fifth for a lot of the time.

Major = Ionian. Lydian has the fourth sharpened.