146 STUDIES IN THE FIELD AND FOREST. 



portion to the entire primitive character of the one and 

 the high state of improven:ient of the other. 



From the earliest period of our history, it has been 

 customary among our people to encourage the multi- 

 plication of swallows, by the erection of bird-houses in 

 their gardens and inclosures. This custom was prob- 

 ably derived from the aborigines, who were in the habit 

 of furnishing a hospitable retreat for the purple martin, 

 by fixing hollow gourds or calabashes upon the branches 

 of trees near their cabins. It is generally believed that 

 these active little birds serve, by their unceasing annoy- 

 ances, to drive away the hawks and crows from their 

 vicinity, performing thereby an essential service to the 

 ' farmer. This pleasing and useful custom has of late 

 years grown unaccountably into disuse. The chatter- 

 ing of swallows is one of the dehghtful accompani- 

 ments of a vernal morning; and that of the martin, in 

 particular, is the most enlivening of all sounds from 

 animated nature. As the birds of the swallow tribe 

 subsist upon insects that inhabit the atmosphere, it is 

 not in our power to increase their means of subsistence. 

 Hence the only means we can use for increasing their 

 numbers is to supply them with a shelter and retreat. 

 By such appliances it would be easy to keep their num- 

 bers up to a level with the quantities of insects that 

 constitute their prey. 



The wren and the bluebird are encouraged by simi- 

 lar accommodations. But as these birds are not social 

 in their habits, a separate box must be supplied for each 

 pair of birds. The wren is an indefatigable destroyer 

 of insects, and one of the most interesting of our fa- 

 miliar songsters, singing like the vireo, during the heat 

 of the day, when most other birds are silent. The blue- 



