The Audubon Societies 



63 



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INCORRECTLY BUILT BIRD-HOUSES 

 One has the opening too low, in the other it is too large 



OPENINGS 



The size and position of the opening are much more important than the 



exact size of the box. A round hole is best, and, except in Martin-houses, should 



be cut above the middle line on one side and preferably about 2 inches from the 



top. All hole-nesting birds, except the Martins, wish to be out of sight of the 



entrance while incubating. There 

 should never be more than one 

 entrance to the box, but if the 

 box is very tightly built, a 

 >^-inch hole may be drilled just 

 beneath the roof for ventilation 

 and another through the floor 

 for drainage. These are unneces- 

 sary however, and in natural 

 nesting cavities, of course, never 

 occur. If there are not many 

 House Sparrows or Starlings about, it is best to make the openings in all the 

 boxes, except those for the largest birds, i}4 inches in diameter. This will 

 admit birds up to the size of the Bluebird and the Tree Swallow, and is not 

 large enough to be objectionable to the Wrens and the Chickadees. If Spar- 

 rows are numerous, one can keep them out of the boxes and still admit the 

 smaller species by making the opening 1% inches in diameter. One can keep 

 out the Sparrows until the Bluebirds arrive by having a removable piece 

 with a small opening fastened over the 1^2 -inch hole. When the Bluebirds 

 are seen trying to get in, this piece can be removed, and then the Bluebirds 

 will have an even chance with the Sparrows. 



If one wishes to build houses for particular birds, the following table of 

 proper diameters for the openings, as given by H. K. Job, will be found valuable: 



(a) ili inches: House Wren, Be- 

 wick's Wren, Carolina Wren, Chickadee. 



(b) 1% inches: White-breasted Nut- 

 hatch, Tufted Titmouse. 



(c) i}4 to i5g inches: Bluebird, 

 Downy Woodpecker, Crested Flycatcher, 

 Tree Swallow, Violet-green Swallow. 



(d) i 3 4 to 2 inches: Red-headed 

 and Hairy Woodpeckers. 



(e) 2^2 inches: Flicker, Saw-whet 

 Owl, Purple Martin. 



(/) 3 inches: Screech Owl, Sparrow 

 Hawk. 



(g) 4^2 inches: Barn Owl, Wood 

 Duck. 



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A HOME-MADE MARTIN-HOUSE AND 



A MARTIN DRIVING AWAY AN ENGLISH 



SPARROW 



