294 THE LOG OF THE SUN 



blood. But this style of architecture seems to 

 answer all the requirements of doves and herons, 

 and, although with one sweep of the hand we can 

 demolish one of these flimsy platforms, yet such 

 a nest seems somehow to resist wind and rain just 

 as long as the bird needs it. 



Did you ever try to make a nest yourself? If 

 net, sometime take apart a discarded nest even 

 the simplest in structure and try to put it 

 together again. Use no string or cord, but fasten 

 it to a crotch, put some marbles in it and visit it 

 after the first storm. After you have picked up 

 all the marbles from the ground you will appre- 

 ciate more highly the skill which a bird shows in 

 the construction of its home. Whether a bird 

 excavates its nest in earth or wood, or weaves or 

 plasters it, the work is all done by means of two 

 straight pieces of horn the bill. 



There is, however, one useful substance which 

 aids the bird the saliva which is formed in the 

 mucous glands of the mouth. Of course the first 

 and natural function of this fluid is to soften the 

 food before it passes into the crop ; but in those 

 birds which make their nests by weaving together 

 pieces of twig, it must be of great assistance in 

 softening the wood and thus enabling the bird 

 readily to bend the twigs into any required posi- 

 tion. Thus the catbird and rose-breasted gros- 

 beak weave. 



Given a hundred or more pieces of twigs, each 



