Source : Webster's Revised Unabridged Dictionary (1913)

Skirl \Skirl\, v. t.& i. [Of Scand. origin, and originally the
   same word as E. shrill.]
   To utter in a shrill tone; to scream. [Prov. Eng. & Scot.]

Skirl \Skirl\, n.
   A shrill cry or sound. [Prov. Eng. & Scot.]

Source : WordNet®

skirl
     n : the sound of (the chanter of) a bagpipe
     v 1: make a shrill, wailing sound; "skirling bagpipes"
     2: play the bagpipes