i6 Bird -Lore 



CHESTNUT-BACKED CHICKADEE 



Last, but not least important, of the numerous Chickadee family is the 

 Chestnut-backed Chickadee, which is the distinctively western species. It 

 inhabits a narrow strip along the Pacific coast from southern Alaska to central 

 CaHfornia, occurring further inland only as a small colony found in northern 

 Idaho and northwestern Montana. Though so restricted in range, it has been 

 divided into four forms: The Valdez Chestnut-backed. Chickadee (Penthestes 

 refuscens vivax) is the most northern, occupying the Prince William Sound 

 region of southern Alaska. The CaHfornia Chickadee {Penthestes rufescens 

 neglectus) is found on the coast of California just north of San Francisco 

 Bay, in Sonoma and Marin Counties. The district between these two 

 subspecies is that assigned to the typical form, the Chestnut-backed 

 Chickadee {Penthestes rufescens rufescens), while south of San Francisco Bay, 

 and extending to the Httle Sur River south of Monterey Bay, is the home 

 of the Barlow Chickadee {Penthestes rufescens barlowi). All these forms are 

 non-migratory. 



Notes on the Plumage of North American Birds 



THIRTY-SIXTH PAPER 



By FRANK M. CHAPMAN 



(See Frontispiece) 



The tameness of Chickadees, their distinctive notes, the conspicuousness of 

 their markings which show practically no variation in color with age, sex or 

 season, combine to make them among the most easily recognizable of birds. 



There is, however, considerable geographic variation among the various 

 species of the genus {Penthestes, formerly Parus), but, since all migrate but 

 little, if at all, two races of the same species are not usually found associated. 

 Black-capped Chickadee {Penthestes atricapillus atricapillus. Fig. 4). 

 As in the other species of the genus, the sexes are alike in color. The winter 

 plumage differs from that of summer only in being more richly colored, the 

 buffy tints being deeper, while the grajdsh margins on the feathers of wings 

 and tail are wider. The young bird, on leaving the nest in its juvenal plumage 

 resembles its parents, but the black crown-cap is duller and the plumage some- 

 what more fluffy. But these slight differences disappear at the postjuvenal 

 molt, after which the young bird cannot be distinguished from its parents. 



In its wide range over the greater part of North America, the Chickadee 

 appears under the following racial names: (i) Long- tailed Chickadee {Pen- 

 thestes atricapillus septentrionalis) . A large pale form of the the Rocky Moun- 

 tain region and eastward to the Mississippi. (2) Oregon Chickadee (P. a. occi- 

 dentalis). A small, dark form of the coast of Oregon and British Colombia. 



