blackcap vs thimbleberry

blackcap

noun
  • Whitebark raspberry (Rubus leucodermis). 

  • A small Old World warbler, Eurasian blackcap (Sylvia atricapilla), which is mainly grey with a black crown. 

  • An apple roasted until black, to be served in a dish of boiled custard. 

thimbleberry

noun
  • The black raspberry, Rubus occidentalis. 

  • Rubus parviflorus, a species of Rubus, native to western and northern North America, from Alaska east to Ontario and Minnesota, and south to northern Mexico. 

  • The fruit of the above plant. 

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