226 PROPAGATION OF WILD BIRDS 



more apt to build high, as are nuthatches and owls. But 

 fifteen to twenty feet is high enough for any of them. Some- 

 times, however, individuals are known to nest higher up 

 than ordinarily. E. H. Forbush has noted bluebirds using 

 a box forty feet from the ground, and martins using houses 

 raised on high cupolas or on top of city blocks. He once 

 saw a pair of chickadees nesting seventy feet from the 

 ground. The exception, however, does not disprove the 

 rule. Birds apparently seek concealment and protection 

 from above as well as from below. 



Poles vs. Trees. The earlier experimenters with boxes 

 placed them mostly on trees, when not on buildings. Now 

 it begins to look as though location on poles or high posts 

 was more attractive to birds. The experience of Mr. For- 

 bush on his place at Wareham, Massachusetts, in 1914, is 

 instructive. Some seasons he has had boxes on buildings oc- 

 cupied, but this year the four so placed were not used. Of 

 twelve in trees in various situations, such as by hedges and 

 on the edge of woods, only one was occupied by flickers, near 

 the house. Nine others were mostly on poles, a few on tele- 

 graph poles or small trees trimmed off, leaving only branches 

 at the top. Of these eight were occupied, the majority 

 by tree swallows, the rest by bluebirds. They were put up 

 too late for chickadees, which usually occupy boxes there. 



Wharton Experiment. William P. Wharton has con- 

 ducted on his estate at Groton, Massachusetts, extensive 

 experiments along this line which are of great value, the 

 results of which he has kindly written out for me. There 

 are two farms several miles apart. One has an area of 

 eighty acres, mostly open land; the other has about 370 

 acres, mainly woodland. The former he has owned for two 

 years, most of the other considerably longer. I quote at 

 length from his letter: 



