U2 LIFE ON THE FARM. 



have long bills, barbed tongues, strong muscles 

 of the head and neck, easily adjustable toes, and 

 stiff tail-feathers,, to enable them to secure insects 

 from the trunks and branches of trees; so swallows 

 have large wings, strong muscles of the chest for 

 support in almost continual flight, long tails for 

 guiding, sharp eyes for seeing, and a very large 

 mouth to enable them to catch insects in mid-air. 



Some insects lead a sluggish life, hiding away for 

 long periods, and moving very slowly within a 

 small sphere; others are very active, flying almost 

 continually in the air. Since different insects have 

 different modes of life, then those animals that 

 prey upon them must adapt themselves to certain 

 conditions in order to secure the necessary supply 

 of food. 



Since some insects burrow in wood, then birds, 

 to secure them, must be able to dig into the wood. 

 Since some insects creep on the ground among 

 grass and weeds, then birds, to secure those kinds, 

 must walk upon the ground, with their bills and 

 eyes- pointed continually downward. Since some 

 'insects spend most of their time flying in the air, 

 the birds that catch them must also fly in the air. 

 It always requires effort to secure food; and this 

 struggle on the part of animals has a tendency to 

 change their structure. 



Now, on account of the large, strong wings, and 

 long, steering tails of swallows, they are able to fly 

 almost continually. This makes them especially 



