1 56 DA VET'S PRIMER 



THE BARN SWALLOW. 



Field observation will convince an ordinarily at- 

 tentive person that the food of swallows must consist 

 of the smaller insects captured in mid-air, or perhaps in 

 some cases picked from the tops of tall grass or weeds. 

 This observation is borne out by an examination of 

 stomachs, which shows that the food consists of many 

 small species of beetles which are much on the wing; 

 many species of Diptera (mosquitoes and their allies), 

 together with large quantities of flying ants and a few 

 insects of similar kinds. Most of these are either in- 

 jurious or annoying, and the numbers destroyed by 

 swallows are not only beyond calculation, but almost 

 beyond imagination. 



Unlike many other groups of birds the six species 

 of swallows found in the Eastern States extend in a 

 practically unchanged form across the continent to the 

 Pacific coast, where they are reinforced by another 

 species, the violet green swallow. 



It is a mistake to tear down from the eaves of a barn 

 the nests of a colony of cliff swallows, for so far from 

 disfiguring a building they make a picturesque addi- 

 tion to it. The presence of swallows should be en- 

 couraged by every device. It is said that cliff and barn 

 swallows may be induced to build their nests in a 

 particular locality, otherwise suitable, by providing 

 a quantity of mud to be used by them as mortar. Barn 

 swallows may also be encouraged by cutting a small 

 hole in the gable of the barn, while martins and white- 



