How is the song of the Ruby-crowned Kinglet often described?

Answer

A rapid, jumbled series of high-pitched trills and chattering notes

The song is recognized as complex and surprisingly long, characterized by a fast succession of high-pitched trills and chattering sounds, sometimes concluding with a sharp 'jrr-jrr-jrr'.

How is the song of the Ruby-crowned Kinglet often described?
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