That western wrens and bluebirds should take as naturally to artificial 

 shelters as did the eastern relatives was to be expected. On the other hand, 

 the use of houses by birds which until recently had persistently ignored them 

 is surprising and must be considered a victory for those who have studiously 

 attempted to enlarge their circle of feathered neighbors. 



Woodpeckers, nuthatches, and titmice excavate their own houses, usually 

 new ones each year, leaving the old homes to less capable architects. Builders 

 of artificial houses generally go to the woodpecker for designs, and by varying 

 st}des to suit the tastes of different kinds of birds, have been rewarded by such 

 tenants as chickadees, tufted titmice, white-breasted nuthatches, Bewick and 

 Carolina wrens, violet-green swallows, crested flycatchers, screech owls, sparrow 

 hawks, and even some of the woodpeckers, the master builders themselves. 

 Flickers readily accept houses built according to their standards. Red- 

 headed and golden-fronted woodpeckers are willing occupants of artificial houses, 

 and even the downy woodpecker, that sturdy little carpenter, has, in one in- 

 stance at least, deemed such a home a satisfactory abode in which to raise a 

 family. Shelters having one or more sides open are used by birds which would 

 never venture into dark houses suited to woodpeckers. They have been occupied 

 by robins and brown thrushes, and, in one instance, by a song sparrow. 



The number of house birds may be still further augmented as time goes 

 on. All of the commoner woodpeckers are likely to be included, as are several 

 of the small owls and wrens, and a few of the wild ducks, as the golden-eye. 

 The wood duck is already known to use nesting boxes. Houses set close to 

 streams in the western mountains will probably be occupied by ousels or dippers. 

 Florida grackles sometimes breed in flicker holes and may be expected to occupy 

 houses now and then. In every locality having trees there is a group of birds 

 ready to appropriate houses when they have the opportunity. 



House birds differ decidedly in their requirements. For those which usually 

 excavate homes for themselves, the diameter of the entrance and the depth and 

 diameter of the cavity must be in accord with their specific standards. Some 

 birds are satisfied with almost any sort of a lodging. Bluebirds and wrens, for 

 example, are content to build in tomato cans, although chickadees and nuthatches 

 disdain them. Wood is better building material than metal or earthenware. 

 Entrance holes should be countersunk from the outside to exclude rain. Heads 

 of nails and screws should be set rather deeply and covered with putty. All 

 houses should be easy to open for cleaning. A perch at the entrance is unnec- 

 essary and may even be an objection, as it is frequently used by English sparrows 

 while they twitter exasperatingly to more desirable occupants. To provide for 

 proper ventilation a row of small holes is sometimes bored just beneath the 

 eaves, but there should never be a ventilating hole lower than the entrance, and 

 joints should be made tight, as drafts of air are dangerous. In case there is 

 danger that rain may be driven in through the door, a small drainage hole, 

 which will be covered by the nest, may be made in the middle of the floor. 



741 



