564 ANNUAL, REPORT SMITHSONIAN INSTITUTION, 1910. 



THE CHICK PLUMAGE. 



The chick plumage is that which appears soon after the chick is 

 hatched, and is completed at the age of about 8 months; that is, 

 when the wing quills are fully ripe, these being the last to complete 

 their growth. The feathers of this plumage are formed of the 

 ordinary quill and plume, the flue of the latter being equally devel- 

 oped on each side of the shaft or stem. The chick feathers are distin- 

 guished from the later feathers by bearing at their tip the natal 

 down feathers, due to the fact that the growth from the birth to 

 the chick feather is continuous; * they also taper toward their free 

 end. The feathers, surrounded by their sheath, begin to make their 

 appearance when the chick is a week or two old, but not all at the 

 same time, the earliest to push out being those over the sides of the 

 hinder part of the body. The flue begins to expand when the chicks 

 are between 3 and 4 weeks old. 



The chick plumage lasts for a varied period, dependent partly 

 upon the nutritive condition and partly upon the strain of the bird; 

 some of the feathers remain on the bird for a year or more, while 

 others are molted before the bird is 6 months old, when there results 

 an intermingling of the chick and ju venal plumages. 



The distinguishing feature of the chick plumage, as of the early 

 plumage of many other birds, is its mottled character, agreeing in 

 this respect with the natal plumage. In the chick, however, the 

 mottling is not due to an intermingling of light and dark feathers, 

 but to the fact that the upper part of each feather is light brown, 

 while the lower part is of a dark gray color (pi. 2, fig. 1). The com- 

 bination of light brown and dark gray colors gives a peculiar mottled 

 or variegated color to the chicks for the greater part of the first 

 A^ear, but is more pronounced during the first six months while the 

 feathers are young and fresh. Chicks from different parents vary 

 much in the proportion of light brown and dark colors on the indi- 

 vidual feathers, and hence in the general light or dark mottled 

 effect of the plumage as a whole. The dark bands on the neck and 

 head are nearly as pronounced as in the natal plumage. 



The various kinds of feathers— body feathers, coverts, and wing 

 and tail quills — now begin to show for the first time those differences 

 which are such a marked feature of the adult. The wing quills 



1 It has recently been shown that in many birds the barbs of the new feather are 

 directly continuous with the barbs of the down feather, no real break occurring between 

 the two. For this reason some writers consider that the down feathers do not represent 

 a distinct plumage, but are to be looked upon as the modified tip of the first true feather 

 (the definitive feather). In the ostrich, however, there is a definite though weak quill, 

 which makes a distinct break between the barbs of the down feather and those of the 

 chick feather. Moreover, the quill of later feathers naturally molted is also continuous 

 with the tip of the new feather, breaking off from it more readily than do the natal 

 feathers on account of its greater weight. 



