American kestrel vs kestrel

American kestrel

noun
  • Any of a species of small falcon, Falco sparverius; a kestrel. 

kestrel

noun
  • Any of various small falcons of the genus Falco that hover while hunting. 

  • The common kestrel, Falco tinnunculus. 

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