18 GENERAL HISTORY I OF BIRDS. 



the adult male. The young male tanager in the spring is less deeply colored than 

 the older bird, and while the rectrices are changed at the spring molt the 

 primaries are retained until the fall molt. In these birds, and indeed in many 

 other cases, there is little or no spring change in the females, simply wear. 

 A familiar case is the Bobolink. Here the adults and young in the fall all 

 assume the Reed Bird plumage. Then early in our spring at their winter 

 home in southern South America the males molt into the familiar black plum- 

 age with yellowish trimmings which as the summer advances wear into the 

 sharply contrasted black and whitish breeding condition. 



Another interesting case is that of the Redstart where the young male 

 instead of changing in spring into the full plumage of the adult assumes a 

 spotted condition in its color values half male and half female, only here and 

 there acquiring a few black feathers, a result which is so irregular that hardly 

 two specimens are alike. In other cases but a slight change is made in the 

 spring, usually on the males only and more often perhaps where there is some 

 prominent coloration of the head as in the Maryland Yellowthroat and the 

 White-throated Sparrow. Again in other cases as in the Snow Bunting there 

 is no spring molt but the breeding plumage condition is attained by the wear- 

 ing away of the weaker colored tips of the feathers so that there is a stronger 

 and sharper contrast of color and markings. Analogous cases occur in other 

 groups as in the water birds, but peculiar conditions also occur, a few only of 

 which can be given here. An adult Cormorant molting in the late summer 

 acquires a suit of richly glossy feathers with many white ones of a different 

 kind decorating the neck, these dropping out in the early spring thuB consti- 

 tuting a winter decoration. On the contrary the immature birds acquire the 

 brown mesoptile plumage soon after leaving the nest, retain it until the mid- 

 dle or latter part of the following summer when they acquire the adult condi- 

 tion, or nearly so. The young male Summer Duck changes its neossoptile 

 feathers, in which it was hatched, while quite small, for a mesoptile plumage 

 very similar to that of the female and then late in summer acquires the rich 

 plumage of the old bird. The adult males, as far as known, change from one 

 rich plumage to another. 



In the Eider Duck a different change occurs. After the breeding season 

 the males lose the strong distinctive coloration and assume a plumage very much 

 like that of the females but with many of the feathers still retaining large areas 

 of white. A month or so later another change takes place; the brown feather- 

 ing is entirely replaced and the bird appears in its full distinctive plumage in 

 which it breeds, plus wearing, in the following summer. For the first change 

 these Eiders retire to the marshes and at the same time loose their flight 

 feathers like many other ducks, all at once. The brown plumage is therefore 

 of value for it serves to hide its wearer in the marsh vegetation during a criti ■• 



