COMPETITION BETWEEN GUILLEMOTS 199 



upon it. It would be useless for an individual 

 to be pugnacious if it had no fixed abode ; 

 equally useless for it to establish itself on a 

 particular ledge if it had no power to defend it — 

 all of which implies an inherited nature similar 

 to that of the Bunting. But the proximate end 

 to which the competition is directed is not alike 

 in the case of both species. In the case of the 

 Guillemot it has reference solely to the piece of 

 rock whereon the egg is laid ; in the case of the 

 Bunting to a piece of ground capable of furnish- 

 ing an adequate supply of food for the young ; 

 and the reason for the difference is this, that 

 there is always an abundance of food in the 

 water beneath the cliff, but breeding stations are 

 scarce, whereas there is always an abundance of 

 situations in the marsh in which the Bunting 

 can place its nest, but the supply of food varies 

 and at times can only be obtained with 

 difficulty. 



If then the Guillemot were to behave after 

 the manner of the Bunting and assign to itself a 

 portion of the face of the cliff, or if it were only 

 to occupy a few ledges, or an even lesser area — a 

 single ledge — what would be the result ? That 

 it would attain to reproduction is beyond 

 question ; that the egg would be safely deposited 

 there can be no manner of doubt ; neither is 

 there any reason to suppose that the offspring 

 would not be successfully reared. But, indi- 

 rectly, its behaviour would affect the Guillemot 

 race. For if it be true, as the crowded ledges 

 certainly seem to show, that there is a dearth of 



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