SOME BIRDS' NESTS 



BIRDS, as everybody knows, make nests, as well 

 as produce young, " after their kind." Over an 

 immensely great area the individuals of a species 

 build their domiciles with an astonishingly close 

 adherence to a uniform architectural plan. The 

 chaffinch, to take an example, ranges from Britain 

 to Japan, with one or two considerable chaffinch- 

 less spaces between ; and the British boy familiar 

 with the bird's dainty structure at home would 

 instantly recognize it for what it is, were he to 

 find it in the land of the Rising Sun. How are 

 we to account for this uniformity of design? 



Up to a certain point there is virtual agreement 

 as to the answer. The form of the nest was struck 

 out or reached by remote ancestors of the 

 chaffinches, succeeding generations faithfully 

 reproducing it in all the lands over which they 

 have since extended their range. To this extent 

 the nest is explained in much the same terms as 

 the bird itself. But the inheritance of structure 

 and the persistence of a complicated act, involving 

 something very like volition and choice, cannot 

 be conveniently further compared. Thus arises 

 the other question : How is the knowledge of the 

 design passed on? To which many naturalists 



