early bird vs premature

early bird

noun
  • A person who wakes early or arrives early, typically before most others. 

premature

noun
  • An infant born prematurely. 

adj
  • Taking place earlier than anticipated, prepared for, or desired. 

  • Suffering from premature ejaculation. 

  • Occurring before a state of readiness or maturity has arrived. 

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