Notes on the Plumage of North American Sparrows 
FIRST PAPER 
By FRANK M. CHAPMAN 
(See Frontispiece) 
N 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 slight 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 Brrp-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: 1 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 obvious 
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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