The Birds' Calendar 



well to know the length of a few familiar birds, 

 which one can carry in mind as standards of 

 measure. As good as any for this purpose are 

 the crow, which is about twenty inches long, 

 the robin, about ten inches, and the English 

 sparrow, or the song sparrow, about six inches. 

 In discovering a new species one is often so 

 excited as to forget entirely to make a note of 

 its size, and on consulting reference - book or 

 stuffed collection he finds he has neglected an 

 essential point of the description, and must wait 

 until the bird favors him with another audi- 

 ence. 



Secondly, as regards the migrations of birds 

 (for, as before shown, there is rarely a specimen 

 and only a very few species resident the whole 

 year at any locality in northern latitudes), the 

 facts are most easily learned from books, al- 

 though by a year's careful observation one can 

 quite accurately classify the summer and winter 

 residents and migrants of his own region. But 

 the further interesting facts of the northern and 

 southern extent of their range in different sea- 

 sons of the year can be learned only by the 

 combined observations of many individuals 

 over a wide extent of territory, and we must 

 rely upon books to tell us, for example, where 

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