WARBLE (3)

War″ble, v. i. 1. 1. To be quavered or modulated; to be uttered melodiously.
Such strains ne'er warble in the linnet's throat. Gay. 3. 3. To sing in a trilling manner, or with many turns and variations. “Birds on the branches warbling.” Milton.
3. 3. To sing with sudden changes from chest to head tones; to yodel.