Birds by Land and Sea 



differences of environment in the case of the 

 guillemot and razorbill, for, wherever there were 

 ledges, there must always have been hollows and 

 crannies also. Just as little can one discern any 

 physical impediment in the guillemot itself to 

 prevent it from covering its egg in what would 

 appear to be a more comfortable and effective 

 manner. We are therefore committed to the 

 position that, whilst so-called instinctive habits 

 arose primarily as variations, it is of the essence of 

 such habits that they do not vary ; and that, whilst 

 pleasure and utility are held to be the principles 

 prompting and confirming such habits, the habits 

 themselves, at times as in the present case 

 are as much opposed to the one as to the other. 



After passing through the puffin area, the north 

 end of the island seemed bare of birds, and it was only 

 when we got round to the east side that they began 

 to increase in number. Here we came to a stretch 

 of cliff which is the site of the principal gullery of 

 the island. The birds at this season were for the 

 most part on the cliff, and not visible from above, 

 except after some slippery work on the rubble at 

 the cliff head. But flying birds soon gave the 

 signal, and the whole colony came out to see what 

 was toward. When we first landed, we thought 

 that we had never heard such a babel of cries as 

 that with which the birds on the west side greeted 

 us, but it was surprising how soon one became 

 accustomed to the sound so as to continue to hear it 



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