NESTS AND NEST-BUILDING IN BIRDS 373 



until the appearance of a nest is presented. At the termina- 

 tion of the breeding season these birthplaces of the young are 

 indicated by circular ramparts, in the composition of which the 

 aromatic nutmeg predominates." Now the fact that birds com- 

 monly acquire a fixed habit of facing one way while sitting over 

 the eggs or young suggests that this "building" of an enclosing 

 wall may not be wholly casual or insignificant. 



