Notes on the Plumage of North American Sparrows 



TENTH PAPER 



By FRANK M. CHAPMAN 



(See frontispiece) 



Indigo Bunting (Passerina cyanea, Figs. 1-3). In juvenal or nesting 

 plumage the Indigo Bunting is a sparrow-like bird, brownish above and 

 obscurely streaked with dusky below. When the tail is fully grown, the outer 

 margins of the feathers are usually faintly tinged with bluish or greenish in 

 the male, but in the female there is generally no trace of these colors. 



The first winter plumage is acquired by partial molt (post juvenal). The 

 underparts are now more or less washed with brown, slightly or not at all 

 streaked, the back is warm, rusty brown. In the male, the lesser wing-coverts 

 are bluish, and the rump and upper wing-coverts are usually bluish basally. 

 This winter plumage is worn until February or March when, as Dwight has 

 shown, through the spring or prenuptial molt most of the body feathers, the 

 tail, and a varying number of the wing-feathers (but never the primary wing- 

 coverts) are lost and the first breeding plumage is acquired. This is usually 

 more or less mottled with remains of the winter plumage, though some indi- 

 viduals look as blue as fully mature birds; but the presence of brown (instead 

 of blue) primary coverts always distinguishes this first breeding plumage. 



The post-nuptial molt, as usual, is complete and the bird now passes into 

 adult winter plumage (Fig. 2) which differs from that of the first winter in 

 having more blue. The following spring, or at the approach of its second breed- 

 ing season, the bird acquires its mature plumage (Fig. i) by molt of most of 

 the body and wing feathers, those of the tail being retained. 



In winter plumage the female generally shows no blue, but after the first 

 spring molt there is usually a tinge on the tail and less frequent in the wings 



(Fig. 3)- 



Blue Grosbeak {Guiraca ccerulea, Figs. 4-6). The nestling Blue Gros- 

 beak, unlike the nestling Indigo Bunting, is unstreaked below, while the first 

 winter plumage is usually wholly without blue. At this season the bird is 

 much like the female figured in the frontispiece (Fig. 6), but lacks the blue 

 tinge on the primaries, there shown. The spring (prenuptial) molt affects most 

 of the body feathers and usually the wdngs and tail, bringing the bird into the 

 mottled costume shown by Fig. 5 in the plate. At the fall (postnuptial) molt, 

 the adult blue plumage is acquired. It is, however, widely margined, partic- 

 ularly above, by rusty brown, which wears away as the season advances and 

 brings the bird into adult breeding plumage without a spring molt. 



The adult female is figured on the plate (Fig. 6), but even the small amount 

 of blue there shown is often wanting. 



(202) 



