160 BIRD STUDIES WITH A CAMERA 
Hence, when Mr. C. J. Maynard visited the Rock 
in 1872, he found that the colony of Gannets on its 
summit contained only five thousand birds, which, 
nine years later, Mr. William Brewster reports had 
decreased to fifty pairs. Mr. Brewster also noted a 
fresh cause for the destruction of the eggs of the 
birds nesting on the sides of the Rock, in the shape 
of acannon which had been introduced shortly be- 
fore his visit. He writes: “ At each discharge the 
frightened Murres fly from the Rock in clouds, 
