OF EASTERN PENNSYLVANIA. 71 



adelphia, stands a certain hollow birch-tree, which 

 has afforded lodgings for a half-dozen individuals 

 of this species, for several successive winters. On 

 the return of night, the birds will precipitate them- 

 selves into the cavity, and closely huddle 

 en masse, until day-break. This habit is not the 

 teaching of a mere blind instinct, but the prompt- 

 ing of a reason, similar in kind but different in 

 degree from that which human beings possess. 



Why so many seek the same cavity is a question 

 which presents itself for solution. May it not be 

 that the above number constitutes the entire 

 family, parents and offspring of the preceding 

 season? As a birch-tree is frequently selected 

 for the site of the nest, this fact lends some aid to 

 the foregoing supposition. 



Another query offers itself for consideration. 

 Why does this species lead a solitary life during the 

 prevalence of winter, and seldom, if ever, hunting 

 in pairs as is the case with Parus atricapillus, but 

 generally found associated with the latter, and the 

 smaller Picida? The answer must necessarily be 

 of a speculative character. The facility with which 

 Woodpeckers discern the lurking places of insects, 

 doubtless, is the cause of this singular association. 

 Experience has taught it the wisdom of such as- 

 sociations, and the advantages which flow there- 

 from. That its selfish propensities should frequently 

 triumph over its better nature, need not be a mat- 

 ter of much surprise. When there is a scarcity 

 of food and its procurement is attended with con- 



