Notes on the Plumage of North American Sparrows 



FIRST PAPER 



By FRANK M. CHAPMAN 



(See Frontispiece) 



IN this series of articles it is proposed to comment briefly on the characters 

 which distinguish the more closely related species and races of Sparrows 

 figured in the accompanying plates, and also to call attention to their sea- 

 sonal changes in plumage. 



Sparrows, like other Passerine birds, are hatched with but a shght downy 

 growth of feathers, well termed by Dwight the "natal down," which, while the 

 bird is in the nest, is succeeded by the juvenal or nestling plumage to the tips 

 of which portions of the natal down are generally attached when the bird leaves 

 the nest. This nestling plumage is shortly succeeded by the winter plumage 

 which is acquired by molt of the body feathers and also sometimes of the wings 

 and tail. 



The adult, following the prevailing law of feather renewal, passes from sum- 

 mer to winter plumage by a complete post-breeding molt. The spring molt is 

 usually not extensive, and, in many species, the change from winter to breeding 

 plumage is accomplished by wear. 



It is proposed, however, to make these papers rather an aid to the identifi- 

 cation of species than a study of molt, and those who are interested in that subject 

 are referred to Dr. Dwight's admirable essay in the Annals of the New York 

 Academy of Sciences (XIII, 1900, pp. 73-360). 



The first five species treated here were figured in the last issue of Bird-Lore; 

 the next four are illustrated in this number, and, hereafter, the text will appear 

 with the plate to which it refers. 



Chipping Sparrow (Dec, Figs, i and 2). The sexes are alike, and in the 

 adult plumage the species does not closely resemble any other of our Sparrows, 

 the chestnut cap, black postocular stripe and black bill being its more ob\ious 

 distinguishing characters. The nestling is streaked below, but fall specimens 

 (Fig. 2, the underparts are here not quite gray enough), both of the adult and 

 young, resemble each other; the crown is now streaked, the postocular stripe is 

 less pronounced, and the bill is dusky. In general pattern of markings the bird 

 now resembles both Brewer's and the Clay-colored Sparrows, but may be easily 

 distinguished by its more rufous color. In the spring, the young bird acquires, 

 and the adult regains, the breeding plumage by partial molt. The Western 

 Chipping Sparrow resembles the eastern species, but is paler, and grayer above. 



Tree Sparrow (Dec, Fig. 3). A blackish or chestnut spot in the center 

 of the breast (which, however, is sometimes barely evident) and a yellow mandible 

 are the Tree Sparrow's chief distinguishing marks. The sexes are alike, and the 

 slight seasonal differences in plumage are occasioned by fading and wear. The 

 nestling is heavily streaked below, but after molting into winter plumage resembles 



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