4 adjectives to describe warble

The formless autumnal warble of the song sparrow is familiar to every one.

The formless autumnal warble of the song sparrow is familiar to every one.

Within the palace he heard some music, as of many instruments cunningly played, and the melodious warble of nightingales and other birds, and by this, and the appetizing smell of many dainty dishes of which he presently became aware, he judged that feasting and merry-making were going on.

The redbreast warbles still, but is content With slender notes, and more than half suppressed: Pleased with, his solitude, and flitting light From spray to spray, where'er he rests he shakes From many a twig the pendent drops of ice, That tinkle in the withered leaves below.

4 adjectives to describe  warble