24 EXTERNAL PARTS 



there great uniformity with birds in this number, but the posi- 

 tion of a bird in a system of classification can often be deter- 

 mined most readily by the number of the primaries and the 

 comparative length of the outer oy first primary . 



Secondaries. — The secondaries vary in number from only six 

 in the English sparrow to upwards of forty in the albatross. 

 These secondary quills are sometimes peculiarly colored ; among 

 some of the ducks they are very bright and iridescent. Such a 

 colored spot on the secondaries is called a speculum^ Sometimes 

 the secondaries are very much enlarged and brilliantly marked, 

 as in the Argus pheasant, and sometimes of remarkable shapes, 

 as in some tropical birds. The inner secondaries are much 

 elongated in the larks and in the snipe, and in the grebes they 

 are all so long as to cover the primaries completely when the 

 wing is closed. In the chimney swift and in the hummingbirds 

 they are peculiarly short. 



Tertiaries or tertials. — The quills growing upon the upper 

 arm — the true tertiaries — are not very evident upon most 

 birds, but two or three of the inner secondaries are frequently 

 conspicuous for either their length or their coloring; these 

 are attached to the elbow and are the feathers which in 

 the descriptions of the birds are generally called tertiaries. 

 Sometimes conspicuously enlarged feathers on the shoulders, 

 though not quills at all, are described as tertiaries. It is 

 unfortunate that there is so little definiteness in the use of 

 this term, but students will usually be right in considering 

 any specially enlarged or peculiarly colored feathers about the 

 shoulders of birds as being called tertiaries, as, for example, 

 the enlarged inner secondaries of the larks, snipes, etc., and 

 the peculiarly marked ones of the sparrows. 



First primary and point of wing. — When qnills are com- 

 pared in length, the comparison refers to the position of their 

 tips when the wing is closed. The iirst primary is the outer 

 one, seen from below, and is often very short, as in the blue- 

 bird ; frequently it is nearly as long as the longest; rarely it is 

 the longest of all. Technically speaking, the expression j^rsi 



