warble1
v.
(of a bird) sing softly and with a succession of constantly changing notes.
▸(of a person) sing in a trilling or quavering voice.
n.
a warbling sound or utterance.
Etymology
ME (as a noun in the sense ‘melody’): from Old North. Fr. werble (n.), werbler (v.), of Gmc origin; rel. to whirl.
warble2
n.
a swelling or abscess beneath the skin on the back of cattle, horses, and other mammals, caused by the presence of the larva of a warble fly.
▸the larva causing this.
Etymology
ME: of uncertain origin.