MINOR MASONS 5 



martins, on the other hand, build by sticking together 

 pellets of prepared road-mud. Most of the material 

 is obtained from the drying puddles on the high- 

 roads. Clearly, if not mixed with anything else, the 

 tendency of these pellets would be to crumble 

 when dry. But the swallow tribe are supplied with 

 a mucous secretion which enables them to gum the 

 particles together. The swallows' nests from which 

 the Chinese bird's-nest soup is made are constructed 

 of this mucous matter only ; while an Indian swift, 

 which builds little boat-shaped nests against the trunks 

 of lofty trees, practically makes them of dried saliva. 



The best mason among the birds of the New 

 World is a potter as well. It is the oven-bird of 

 the pampas. It is called the casara, or house-builder, 

 by the Spaniards. The nest is made of mud and bits 

 of straw, practically the same as the material used for 

 most buildings in Mexico. The walls are very thick, 

 and there is a partition wall inside, reaching so high as 

 to form an antechamber. Except the beaver (which is 

 such an accomplished designer that he must be con- 

 sidered an engineer rather than a mere mason) and 

 certain rats which build walls of stones and of thorns 

 to keep out snakes, there are few masons among mam- 

 mals. But the methods of the swallows and martins 

 are closely imitated by the greater number of minor 

 masons, from perfect insects such as the mason wasps 

 and bees down to the sea-worms that build themselves 

 tubes of feand. The general principle is to make pellets, 

 and then to harden and join them by some secretion, 

 though sometimes this home-made mortar is only 



