cockerel vs fledgling

cockerel

noun
  • A young male chicken. 

fledgling

noun
  • A young bird which has just developed its flight feathers (notably wings). 

  • An insect that has just fledged, i.e. undergone its final moult to become an adult or imago. 

  • An immature, naïve or inexperienced person. 

adj
  • Emergent or rising. 

  • Untried or inexperienced. 

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