warble

1 :  to sing in a trilling manner or with many turns and variations

2 :  to become sounded with trills, quavers, and rapid modulations in pitch

3 :  sing

:  to render with turns, runs, or rapid modulations :  trill

1 :  a swelling under the skin especially of the back of cattle, horses, and wild mammals caused by infestation with maggots of a botfly or warble fly

2 :  the maggot of a warble fly

1 :  low pleasing sounds that form a melody (as of a bird)

2 :  the action of making low pleasing sounds that form a melody

:  to sing a melody of low pleasing sounds

1:  a swelling under the hide especially of the back of cattle, horses, and wild mammals caused by the maggot of a botfly or warble fly

2:  the maggot of a warble fly