46 BIRD FRIENDS 



young usually resemble them, as in the case of the 

 chickadee. But in the case of the red-headed wood- 

 pecker, the young lack the brightly colored feathers 

 that both adults possess on the head. 



The color of a bird may also change according to 

 season. In the case of those birds in which the male 

 and female are differently colored, the male has two 

 distinct plumages, that of the summer, which is usu- 

 ally conspicuously colored, and that of the winter, 

 which is usually dull-colored. And during the two 

 moulting periods when the bird is changing from one 

 plumage to another, it may show a partial combina- 

 tion of both plumages. 



Differences in sex. Some species of birds show a 

 difference in color between the male and the female. 

 Sometimes this difference may be slight, as in the 

 yellow warbler, Baltimore oriole, and bluebird, in- 

 volving only different shades of the same color; or 

 it may be extremely conspicuous, involving an entire 

 change of color, as with the red-winged blackbird 

 and its sparrow-like mate, the scarlet tanager and 

 its greenish mate, the rose-breasted grosbeak and its 

 brownish mate. Other examples are the indigo 

 bunting, goldfinch, and bobolink. 



Protective coloration. Naturalists are not agreed 

 as to the significance of the extremely bright colors 

 found on some birds, but it seems to be a very gen- 

 eral law that the coloring of many birds is such as 

 to render them inconspicuous and thus furnish pro- 



