INTRODUCTORY CHAPTERS. 



felt, the second moulting occurs, and the feathers that have 

 borne the wear and tear of winter give place to the fresh 

 new coat, and the bird throat swells with the Spring Song. 



From a residential standpoint, we have four distinct 

 grades of birds to consider: 



I. The summer residents : Those birds which, coming to 

 us in the spring, rear their young, and after shifting 

 about somewhat in late summer, retreat more or less 

 southward for the winter. 



II. The residents: Comprising those species which are 

 represented by individuals all the year round. 



III. The winter residents : The birds who are inhabitants of 

 boreal regions, breeding beyond the northern border 

 of the United States, coming only to us in winter, 

 and retiring northward at the time of the general 

 upward migration. 



IV. The migrants : Birds that are with us for a few weeks 

 in spring, en route from the south to their more 

 northern breeding haunts, and are also visible for a 

 similar period during the return trip in autumn. We 

 may class with these the casual visitors that appear 

 for a brief visit either summer or winter. 



The two movements of bird life in spring and fall are 

 known as the great migrations, some birds being plentiful 

 in spring and quite rare in the autumn, and vice versa, as 

 the path chosen for the upward and downward trip may not 

 be the same. The individuals belonging to these classes will 

 be specified in turn, and they are mentioned here to show 

 you that if you do not begin the bird-quest in spring, in time 

 to meet the army of migrants, you may miss some of the 

 most interesting species. 



Conspicuous among the birds that lodge with us in April 

 and May, letting us hear their song for a brief period, is the 

 great Fox Sparrow, the White-throated and White-crowned 

 Sparrows, the group of lovely Warblers, and, best of all, 

 the Hermit Thrush, whose heavenly notes of invocation, if 

 once heard, are never forgotten. 

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