Song Birds and Water Fowl 



of their peculiar structures, and their lack of 

 timidity gave good opportunity to watch the 

 process. This nest differs from that of all our 

 other birds in having its walls composed en- 

 tirely of mud, which the bird moulds into little 

 pellets, fastening them together with its own 

 saliva ; and thus the entire nest, which is very 

 thick and heavy, is supported only by adhesion 

 to the wall against which it is built. The 

 architectural taste of these swallows involves a 

 peculiar difficulty and danger, for the nest must 

 always be placed where it will be protected 

 from the rain by an overarching projection ; 

 otherwise, from the added weight of moisture, 

 and its disintegrating effect, it would suddenly 

 collapse in a storm. The rounded form of the 

 pellets gives the exterior of the nest a peculiar 

 corrugated appearance, but the inner surface is 

 perfectly smooth. From its situation it results 

 that the cavity is like a pocket, bending out 

 horizontally at the top to afford egress. After 

 the birds had worked diligently several days, I 

 found, one morning, that some of the nests had 

 fallen to the ground. But, without wasting 

 precious time in vain regrets, they began at 

 once to repair the loss. Everything went 

 smoothly until the nests were almost completed, 



