eiderdown vs serape

eiderdown

noun
  • A quilt stuffed with this down. 

  • The down of the eider duck, used for stuffing pillows and quilts. 

serape

noun
  • A type of blanket worn as a cloak, especially by Spanish-Americans, or used as a saddle blanket. 

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