W. p. PYCR AIT : NEST ( )F THE RINGED PLOVER. 377 



the more astute parents would leave progeny. Perhaps 

 we should regard those individuals which make no j)retence 

 at nest-building" as birds which have lost the earlier habit. 

 The need for such preparation being apparently slight, 

 the stimulus has lost its force. Where the nest-building 

 habit still persists, we may imagine this stimulus to 

 have been transmitted unimjjaired, because more strongly 







>^J 



\'"-'4r5l^^ 



'"— V-''^'^ ■^'' 



Fig. 2. — Nest of Ringed Plover : comi^osed of small pieces of stone. 

 (Photographed by C. W. Colthrup. ) 



developed in their ancestors. But this, of course, is mere 

 hypothesis. 



Admitting the possibility of this interjDretation we come 

 to the second question. — -What induces the choice of 

 materials ? That is to say, what induces some individuals 

 to choose shingle, some shells, some wood-fragments, and 

 others green vegetable matter? Do these birds act on 

 suggestion? Having acquired the instinct to prepare a 



