288 BIRD FRIENDS 



development of the land for real-estate purposes, 

 and hence there may be emphasized the necessity 

 of building nesting-houses if we would keep these 

 birds around our homes. The problems which arise 

 in connection with the construction and location of 

 bird-houses should be talked over with the children 

 and the important precautions to be observed ex- 

 plained to them. The really essential features hav- 

 ing been made clear, the children should be allowed 

 to use their ingenuity and individuality about ar- 

 ranging details. 



Difficulties. The children should understand the 

 difficulties to be met, so as to avoid undue disap- 

 pointment, and should be prepared to overcome 

 them as far as possible. The greatest obstacle of all 

 is the English sparrow. Some devices which may as- 

 sist in keeping this bird away have been discussed 

 in Chapter XIX, the most effective one of which is 

 to make the hole so small that the sparrows cannot 

 enter, but large enough for the wren and chickadee. 

 With houses for bluebirds and tree swallows, prob- 

 ably the most effective thing which the children can 

 do is to make the houses so that the tops can be 

 easily lifted, and then to remove the sparrows' eggs 

 once a week or as fast as they are laid. This often 

 causes the sparrows to leave the nesting-house. If 

 nothing else can be done the entrance can be cov- 

 ered or the house taken down, as soon as it is evi- 

 dent that no other bird is going to use the house, 



