songbird vs yodeler

songbird

noun
  • Any bird in the passerine suborder Passeri, which are distinguished by a more sophisticated vocal apparatus 

  • A bird having a melodious song or call. 

yodeler

noun
  • One who sings so that their voice fluctuates rapidly between their normal chest voice and a falsetto, one who yodels. 

How often have the words songbird and yodeler occurred in a corpus of books? (source: Google Ngram Viewer )