squawker vs squeaky wheel

squawker

noun
  • A person who complains or protests noisily. 

  • An informant; a stool pigeon. 

  • A loudspeaker used for frequencies intermediate between those of a woofer and a tweeter. 

  • Something that squawks. 

  • The radio used in police vehicles to keep in contact with headquarters. 

squeaky wheel

noun
  • A complainer; one who speaks out when there are problems. Often used pejoratively. 

  • Of several problems, the most apparent or the most urgent. 

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