1472 BIRDS 



to such the term thread feathers is applicable. Finally, the feathers covering the 

 body and concealing the underlying down are conveniently referred to as the 

 con tour feathers. 



Instead of being evenly distributed over the- body of a bird, the feathers grow 

 from certain well-defined tracts, between which are bare spaces. Although such 

 tracts have received distinct names, and are of some importance in classification, it 

 will suffice to mention their mere existence; and we pass on to the consideration of 

 the names applied to the feathers of the tail and wings. 



As shown in the diagram on p. 1470, the tail feathers, which are very generally 

 twelve in number, are termed rectrices, and are usually firm and fully developed. 

 Above and below the rectrices are the upper and under tail coverts; although gen- 

 erally small and unimportant, in the peacock the upper tail coverts attain an ex- 

 traordinary development, and constitute what is commonly designated the tail. 

 Premising that the feathers clothing the shoulders are termed scapulars, and those 

 between them inter scapulars, we pass on to the consideration of the feathers of the 

 wings. First of all, we have the little group of feathers forming the bastard wing, 

 or alula, which are carried by the first digit, or thumb, and lie on the front border 

 of the back of the wing. Next, we have the flight feathers, remiges, or quills, 

 which arise from the bones of the arm and pinion (or hand, exclusive of the 

 thumb) ; all are strong, firm feathers, giving rise to the main contour of the wing. 

 Such of the remiges as take their origin from the pinion are termed primaries; while 

 those attached to the fore-arm (ulna) and upper arm (humerus) are entitled second- 

 aries, though the remiges arising from the humerus used to be distinguished as 

 tertiaries, and the term secondaries confined to those attached to the ulna. The 

 primaries are the firmest and stiffest of the wing feathers, and are very generally 

 either nine or ten in number. As the rectrices of the tail have tail coverts, so the 

 remiges have wing coverts, both above and below. Of the upper wing coverts, we 

 have first the primary coverts overlying the primaries; while the secondaries are 

 overlain by three series, respectively known as the greater, median, and lesser upper 

 secondary wing coverts. Of these the greater coverts are the largest and the most im- 

 portant in classification. The under wing coverts, which are less important in classi- 

 fication, are likewise divided into a primary and secondary series. 



When first hatched, Birds are covered with some kind of down, 

 & pf e very scanty in those which are reared in nests, but thick in all those 



able to run about at the time of birth. The true feathers are, how- 

 ever, soon developed, those of the wings and tail being usually the first to make 

 their appearance, and the rapidity with which feathers grow is one of the most re- 

 markable features of Birds. In order to preserve the plumage in good condition, 

 it is essential that it should be renewed at least once a year. This renewal of the 

 feathers is termed molting, and frequently takes place twice during the year; 

 while in the ptarmigan there are three molts. The chief molt usually takes 

 place soon after the breeding season; but in those birds which, like ducks, have a 

 special breeding plumage, a second molt takes place previous to that period. In the 

 ptarmigan the third molt is for the assumption of the white winter dress. Usually 

 the wing feathers are shed in pairs one after another; but among the ducks, which 



