AIDS TO NESTING 231 



northerly exposure. Birds do not like it so well, and might 

 reject boxes thus placed, though Mr. Forbush has noticed 

 that they sometimes take a box with northerly frontage if 

 the cavity is deep. The young, however, are more liable 

 to perish in storms. 



Example from Martin Houses. The matter is well il- 

 lustrated in the case of martin colonies. Mr. Forbush says 

 that in a large compartment house they first occupy the 

 rooms opening south and west, leaving those north and 

 east to latecomers. In cold storms, when the young die, 

 the casualties are first in the north and east compartments. 

 As they require the holes to be near the floor level, they are 

 more exposed than species using deep holes. Another item 

 noticed by Mr. Forbush is that other species will occasion- 

 ally use a box with the hole low down if it faces south and 

 west, but not if in the other direction. 



Not among Branches. People often put up boxes on the 

 trunks of trees near the junction of one or more branches. 

 Birds evidently dislike tliis. for such boxes are frequently 

 not occupied, unless by wrens. Such branches make good 

 perches for cats while they reach in and pull out the young. 

 If on a tree at all, the box had better be fastened to the 

 trunk away from limbs, and also not up among the foliage 

 of the tree, where squirrels can jump to it easily. 



Not Slanting Back. One of the points made by Baron 

 Von Berlepsch in describing the proper placing of boxes is 

 that these should not be set with the bottom projecting, 

 causing the top to slope back, and leaving the entrance more 

 exposed to the beating in of rain. 



Cleaning House. In autumn, or certainly before spring, 

 the nesting-boxes should be cleaned out. Old nests should 

 always be removed, as most birds prefer to build their own, 

 and seldom occupy a nest the second time. Squirrels and 



