The Birds' Calendar 



ent for its validity upon the particular geo- 

 graphical location of the observer, this third 

 method is conditioned by some very interesting 

 facts of science, viz., the laws governing their 

 appearance and disappearance, as they come 

 and go periodically. 



As the object of these pages is not merely to 

 give a succinct account of the several species 

 one is likely to find in the course of a year's 

 observation, but to make the whole scheme of 

 bird -life more intelligible by treating briefly 

 of the more important phenomena observable 

 among them collectively, it is essential to speak 

 of that curious and extremely interesting phase 

 of their history — bird-migration ; and no time 

 is more opportune for this explanation than 

 February — ''so full of frost, of storm, and 

 cloudiness, ' ' so unfavorable for outdoor study, 

 and immediately preceding the first of the 

 year's migrations. 



Even the most unobservant person is prob- 

 ably aware that the robins and bluebirds ar- 

 rive in the spring, and go away some time in 

 the fall ; but he is not so likely to know that, 

 on the other hand, there are many species, un- 

 known to him by name or appearance, like 

 kinglets, nuthatches, crossbills, shrikes, pine 



48 



