180 CONSERVATION OF CANADIAN WILD LIFE 



of boxes was increased yearly until, in 1911, there were 347 

 boxes, of which 66 per cent were occupied.* I am informed 

 that in 1913, 75 per cent of the boxes were occupied. 



The nesting-box that I have described above can be 

 made in different sizes to suit the various classes of birds 

 that it is desired to encourage. The following dimensions 

 are modified from Farmers' Bulletin No. 609 of the United 

 States Department of Agriculture: 



Inside 

 Dimen- 

 sions of 

 Cavity 



Depth of 

 Cavity 



Entrance 

 Above 

 Floor 



Diameter 



of 

 Entrance 



Height 

 of Box 

 Above 

 Groimd 



Wrens and chickadees . . 



Bluebird and tree swal- 

 low 



Flicker . . . 



Downy woodpecker .... 



Screech owl and spar- 

 row hawk 



Inches 

 4x4 



5x5 



7x7 

 4x4 



8x8 



Inches 



7 to 9 



6 to 8 

 16 to 18 



8 to 10 



12 to 15 



Inches 



6 

 16 



8 



12 



Inches 



VA 



2H 



Feet 

 6 to 12 



5 to 15 



6 to 20 

 6 to 20 



10 to 30 



Nesting-boxes for certain birds that do not nest in cavities 

 may be made with open tops, and placed in sheltered places, 

 such as under the eaves of buildings or verandas. The 

 sizes for such boxes are as follows: 



Robin Sides 6 inches by 8 inches; depth 4 inclies 



Phoebe and barn swallow " 6 " "6 " " 3 " 



In the aforementioned Farmers' Bulletin designs of differ- 

 ent kinds of nesting-boxes are given. 



In many parts of the country, houses for purple martins 

 may be seen erected on poles. Such houses are also used 

 by tree swallows. They are generally built on the colony 

 plan, as these birds are gregarious in their habits, and their 



* For further particulars and illustrations see my memoir on "The Large 

 Larch Sawfly," Bull. 10, Second Series, Experimental Farms, Dept. Agricul- 

 ture, Canada, 1912, 



