178 CONSERVATION OF CANADIAN WILD LIFE 
their companions had gone during the winter and after 
their breeding-time. Similar observations were made dur- 
ing a plague of the same insect (Tortrix viridiana) in the 
grand duchy of Hesse, where the protection of birds has 
been carried on in a sensible and energetic fashion for over 
ten years. Of 9,300 boxes hung up by the government in 
the state and communal woods of the grand duchy of 
Hesse, 70 to 80 per cent were occupied in the first year, and 
in 1907 all were inhabited. On and near Baron von Ber- 
lepsch’s Seebach estate, 90 per cent of 2,000 nest-boxes in 
one wood were occupied, and nearly all of 500 and 2,100 in 
other localities. In Hungary similar measures are taken, 
largely owing to the admirable work of Otto Hermann, one 
of the foremost European advocates of bird-protection. 
Some years ago, when investigating the depredations of 
the larch sawfly (Nematus erichsonii) in the English Lake 
District, I was impressed with the value of birds as natural 
means of control, and, as birds in the worst-infested district, 
namely, Thirlmere, were not so abundant as they should 
have been, it was recommended that they should be pro- 
tected and encouraged by means of nesting-boxes. The 
corporation of the city of Manchester owns Thirlmere, this 
lake being their water supply, and they distributed nesting- 
boxes of the pattern which I devised and which is illustrated 
herewith (Fig. IV). The advantage of this box was that it 
could be made out of the slabs or rejected outer portions of 
the lumber bearing the bark. Three equal lengths of the 
slab are nailed together to form three sides of a long box, 
the outside of which, bearing the bark, was round and the 
inside square. The fourth side is made of a flat piece of 
wood forming the back of the box; this piece is longer than 
the other sides, and projects above and below the box, 
thus providing means of attaching the box to the tree. 
The top and bottom of the box may be made of slab 
wood. Several holes should be bored in the bottom, which 
