BIRD ROCK 183 
guished in these pictures and are therefore grouped 
under one head, it being calculated that about from 
fifteen hundred to two thousand individuals of these 
species make the Rock their home. Of this number 
probably not more than one hundred are Puffins, 
while the Common and Briinnich’s Murres (Uria 
troile et U. lomvia) outnumber the Razorbills at 
least four to one. 
The Kittiwake population of the Rock probably 
numbers between six hundred and eight hundred 
98. Gannets. x 8. An enlarged detail of No. 99. 
birds; of Gannets, there are perhaps left only fifteen 
hundred of the more than one hundred thousand 
