warbles is a form of:

Warble




SEE: Wormil
ENGLISH MEANING
noun
1.
A small, hard tumor which is produced on the back of a horse by the heat or pressure of the saddle in traveling.
2.
A small tumor produced by the larvae of the gadfly in the backs of horses, cattle, etc. Called also warblet, warbeetle, warnles.
3.
A quavering modulation of the voice; a musical trill; a song.
verb
1.
(TRANSITIVE) To sing in a trilling, quavering, or vibratory manner; to modulate with turns or variations; to trill; as, certain birds are remarkable for warbling their songs.
2.
(TRANSITIVE) To utter musically; to modulate; to carol.
3.
(TRANSITIVE) To cause to quaver or vibrate.
4.
(INTRANSITIVE) To be quavered or modulated; to be uttered melodiously.
5.
(INTRANSITIVE) To sing in a trilling manner, or with many turns and variations.
6.
(INTRANSITIVE) To sing with sudden changes from chest to head tones; to yodel.