Can necessarily mean “the alternation of two musical tones a diatonic next aside” or “a seem resembling a musical trill.” The flute-like trill of the wood thrush is perhaps the most gorgeous tune of any North American chicken. The descending trill of its relative the veery isn’t also shabby, either. https://bookmarklinking.com/story4048247/detailed-notes-on-birdwithmostwords-com