Can signify “the alternation of two musical tones a diatonic second apart” or “a seem resembling a musical trill.” The flute-like trill from the Wooden thrush is Probably the most beautiful track of any North American hen. The descending trill of its relative the veery isn’t much too shabby, either. https://mypresspage.com/story3730665/birdwithmostwords-com-no-further-a-mystery