Sky Sweepers 253 



must always have been known to people. In many cases, the 

 disappearance of their original type of nesting sites has caused 

 them to live in structures erected by man. Usually the birds 

 feed at a level low enough to be seen easily. They take in- 

 sects stirred up by the feeding chickens and the moving live- 

 stock. They are friendly, gregarious in their habits, and nu- 

 merous. They are so well known that they are mentioned in 

 history, fable, folklore, and legend. They were referred to 

 in early literature. I wondered what these early writers knew 

 and thought about them. Perhaps a sketchy sampling of early 

 writing might give information concerning these birds and 

 the general status of bird knowledge, as well. 



Aristotle, the Greek philosopher who lived in the fourth 

 century B.C., had discussed them. He wrote that some birds 

 had feet of little power so they were called apodes. Such 

 birds were powerful on the wing and, as a rule, birds which 

 resembled them were weak-footed and strong-winged like 

 the swallows. Their nest building denoted great intelligence: 

 the swallows mixed mud and chaff together and, if mud were 

 not obtainable, they made their own by sousing their bodies 

 in water and rolling about in the dry dust. Parents cooperated 

 in the training of their young, feeding the nestlings each in 

 turn, removing droppings from the nest at first until the 

 young themselves learned cleanliness. He said that the swal- 

 lows bred twice a year instead of once as did most other 

 birds. Swallows are among the worst enemies of bees. He 

 described the position of the bird's gall bladder and the 

 shape of its stomach. He thought that some birds practiced 

 hibernation and swallows were among them. They had often 

 been found hidden in holes, quite denuded of feathers. 



He might have gotten away with such a talk today if he 

 had delivered it to people who had paid little attention to 

 nature. It indicated field observation, examination by dissec- 

 tion, and an attempt to draw conclusions from the evidence. 

 There were some obvious errors but there was enough truth 



