THE EAVES-SWALLOW. 209 



way that led to a round and- comfortable chamber. Though 

 not pretty, this nest was very ingenious, and it answered per- 

 fectly the swallow's requirements. 



To-day the swallow makes a very different nest. It is a 

 little pocket hung against the wall of the barn close under the 

 eaves, partly supported by the side of the barn, partly by the 

 roofing eaves, with no tunnel to enter it and no mud roof. 

 Instead of being like a mud bottle, complete but for the bottom, 

 which the rock supplied, the commonest form to-day resembles 

 a quarter section of an orange peel stuck up beneath the rafters 

 and entered by a hole scooped out at the top. 



Why has the swallow changed her architecture within fifty 

 years ? All the older swallows built mud bottles even for 

 years after they frequented barns. Your grandfather will tell 

 you that when he was a boy he saw nothing else. Yet you 

 perhaps never saw one in your life. 



The swallow is a bird that learns much by experience. 

 When she first began nesting against barns she had a great 

 deal of trouble. A modern barn presents quite a different 

 problem from a cliff of rock or a bank of hard clay. In the 

 first place, it is much smoother, and it is much more nearly 

 perpendicular, so it offers no natural support to the nest. We 

 speak of perpendicular cliffs, but we rarely see one. The partial 

 support that the slope of the cliff afforded was wanting in the 

 barn. Then, the rock was always moist while the barn grew 

 very dry in summer. The moisture that condensed upon the 

 rock was just sufficient to keep the mud from growing too dry 

 at the point of contact, so the nest held securely. But the dry 

 boards robbed the nest of its natural moisture, and the rack- 

 ing of summer tempests, or the jar of heavy carts across 

 the barn floor, or the weight of the birds in the nest, would 

 often send the whole household tumbling to the ground. 



