squawker

noun5

1. •
   Something that squawks.
2. •
   A person who complains or protests noisily.

   • The bosses grow weary of the scammers and squawkers and conclude that they're all a big nuisance. — 2001
3. •
   (slang) The radio used in police vehicles to keep in contact with headquarters.
4. •
   A loudspeaker used for frequencies intermediate between those of a woofer and a tweeter.
5. •
   (slang) An informant; a stool pigeon.