BIRD-PROTECTION IN SCHOOLS 141 



numbers of these birds. 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 ob- 

 served explained as discussed in Chapter ii. The 

 really essential features having been made clear, 

 the children should be allowed to use their in- 

 genuity and individuality about arranging other 

 details. 



Difficulties. — The children should understand 

 the difficulties to be met, so as to avoid undue 

 disappointment, and should be prepared to over- 

 come them so far as possible. The greatest ob- 

 stacle of all will be the English sparrow. Some 

 devices which may assist in keeping this bird 

 away have been discussed in Chapter ii, 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 blue- 

 birds' and tree swallows' houses probably the most 

 effective thing which the children can do is to 

 make the houses so that the top may be easily 

 lifted, and then to remove the eggs of the spar- 

 row once a week or as fast as they are laid. But 

 in no event should the sparrow be allowed to 

 rear young. If nothing else can be done, the 

 entrance holes should be covered, or the house 



