blackcap vs laughing gull

blackcap

noun
  • 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. 

  • Whitebark raspberry (Rubus leucodermis). 

laughing gull

noun
  • An American gull (Leucophaeus atricilla); in summer the head is nearly black, the back slate color, and the five outer primaries black. 

  • A common European gull (Xema ridibundus). 

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