CHAPTER VII 



NESTS OF BIRDS 



Every schoolboy knows the difference between 

 a blackbird's and a thrush's nest. Here we 

 have two distinct birds closely allied and of 

 much the same habits, building their nests in 

 similar situations and using the same kind of 

 materials, but, with this marked difference, 

 that whereas the blackbird's is lined with dead 

 grasses, the thrush plasters the interior of her 

 structure with mud which on drying becomes 

 as hard and smooth as the inside of a cup. 

 And so with the thousands of different kinds 

 of birds all over the world ; no two distinct 

 species build exactly alike. In some cases the 

 difference is so slight that the casual observer 

 is puzzled to tell them apart, but the expert 

 has but to see an empty nest to identify the 

 architect. 



Some nests of our British warblers — ^the 

 whitethroat class, for instance, are almost 

 identical. These structures consist solely of 

 dead grass-stems with a lining of hair, but 



