THE CRUDEST NEST FORMS 63 



often being scanty and generally arranged in a loose 

 and slovenly manner. The Crows and Rooks, although 

 employing much the same materials, are more care- 

 ful and elaborate builders ; whilst the Jay is an even 

 better architect, its nest being to some extent a re- 

 capitulation of and improvement on those of the species 

 already instanced. Last and most perfect nest-builder 

 of all we have the Magpie. The nest of this bird is a 

 masterpiece of its special type, an example of avine 

 intelligence and skill that it would be hard to beat, 

 embodying all the principles of those of its kindred, 

 from the mere platform of sticks to the neatly-lined 

 structure, and finally crowned with a roof of basket- 

 work that renders it almost impregnable. Lastly, we 

 may mention the group of Warblers, known more 

 familiarly as " Willow Wrens," as furnishing instances 

 of progressive types of nest-building. So far as is 

 known, these birds all build nests of a very similar 

 type, more or less domed, but the degree of finish 

 varies considerably. Some of the species build nests 

 of dry grass with little or no lining ; others add a little 

 hair (as in the Wood Wren), whilst the most elaborate 

 architects finish off theirs with a warm and plentiful 

 bed of feathers, as for instance the Willow Wren and 

 the Chiffchaff. Now, looked at from one point of view, 

 all this gradation of nest in certain groups (and many 

 other instances might have been given) seems to 

 suggest a gradual development of nest-building capa- 

 bilities — improvements upon certain primitive types, 



