118 PROCEEDINGS OF THE ACADEMY OF [1896. 



Savanna Sparrow and Sharp-tailed Finch are interesting exceptions 

 to the latter statement. 



The annual molt which occurs at the close of the breeding season, 

 in late summer or early fall, is common to all birds, and is generally- 

 coincident with the molt of the first plumage of the young birds of 

 the first broods, varying, however, in this respect in diflferent species. 

 The annual molt is always complete, and when the new feathers 

 are assumed, the plumage is richer in color and fuller than at any 

 other time. In the breeding plumage, the colors may be in stronger 

 contrast, but this is generally due to the wearing away of the blend- 

 ing colors of the tips of the feathers^ which necessarily makes the 

 plumage rougher. 



CHANGE OF COLOR BY ABRASION. 



During the time intervening between two molts, the feathers 

 undergo a certain amount of abrasion. In such birds, specimens taken 

 just before the annual molt, present a very dilapidated appearance, 

 and the abrasion, combined with bleaching, has generally altered the 

 appearance of the plumage very materially from that of the preced- 

 ing fall. 



While this effect of abrasion is seen in the plumage of all birds 

 just before the annual molt, the feathers of some are so constructed 

 as to render possible a complete change in the color of the exposed 

 plumage by abrasion, long before the time when the eflTects of the 

 general wear and tear above described are apparent. These feathers 

 have their terminal portion difierently colored from the basal, so that 

 when the plumage is in its normal " shingled " position, only the 

 terminal part of each feather is exposed, and the general color of 

 the plumage is the same as this portion of the feather. By the loss 

 of this terminal portion, the diflTerently colored base of the feather 

 comes into view and the general color of the plumage is thus com- 

 pletely changed (PI. IV, fig. 7). This result is attained by general 

 wear and tear and also, doubtless, by the agency of the bird itself in 

 preening its feathers. 



The diflTerently colored tips to these feathers wear off very 

 rapidly, and generally disappear entirely before any perceptible 

 wear is noticeable on other parts of the plumage which are uniform 

 in color. This would indicate that the terminal portions of these 

 feathers are more brittle than the basal part, especially as the breadth 



Except when a complete spring molt occurs. 



I 



