Can necessarily mean “the alternation of two musical tones a diatonic second apart” or “a seem resembling a musical trill.” The flute-like trill of the wood thrush is perhaps the most wonderful tune of any North American chook. The descending trill of its relative the veery isn’t also shabby, either. https://bookmarkinglive.com/story19051344/the-single-best-strategy-to-use-for-birdwithmostwords-com