A TERN COLONY 137 



ness of absolute contrast from a ground on which 

 they form the only contrast. 



But if the terns have no notion of selecting the 

 best places for the concealment of their eggs, 

 the colony, excepting those members of it which 

 lay on the sandy extremity, do seem to follow a 

 method in nest -making. Moving at random from 

 clutch to clutch, one is struck by their extreme 

 variety of practice in this respect. Here the eggs 

 are deposited on the ground with no rest what- 

 ever ; there on the merest perfunctory sketch 

 of a nest ; and here, again, on quite a massive 

 and elaborate bed. But soon something suggest- 

 ing an order is discernible. There on the outer- 

 most beach, which is strewn with bunches of dried 

 seaweed, the birds construct a bulky nest. They 

 rarely lay on one of the bunches provided by 

 Nature, but the collection made by themselves 

 resembles one of these. The whole nest, there- 

 fore, fits into its surroundings. The sketchy nests 

 are found on the inner beach, where the patches 

 of stonecrop occur ; and as they are made of 

 the dead fibre of this plant, they closely resemble 

 those numerous patches of it which have 

 succumbed to the aridity of the situation. Among 

 the lichen-spotted stones the terns make no nest 

 whatever, and, as has been said, those which select 

 this situation achieve, in the matter of conceal- 

 ment, the largest success. 



It is not improbable that in a modification of 

 habit we should seek the explanation of the tern's 

 haphazard use, or no use, of the protective colour- 

 ing of its eggs. Almost certainly the general 



