A player would toot a melody; the bird would record it and warble it back.

In the swamp in secluded recesses, A shy and hidden bird is warbling a song.

Some bird or other warbled and chirped in the distance, and the humid air was heavy with pungent aromas.

AN unfamiliar bird warbles from beyond the olive groves.

A yellow bird far above us warbled as though its heart would break.

There's where the birds warble sweet in the spring-time.

Concealed by those new leaves, birds chirped and warbled.

Click the button and the bird warbles its distinctive song.

An invisible bird warbled an intermittent curtain of sound.

Haunting songs came through the evernight, as alien birds warbled their secrets.