INTRODUCTION. 17 



of the snipe's wing (Figure 52) illustrates this; the greatest distance which 

 can be measured on this cut is the length of the wing. Second, length of tail 

 or "tail." This is practically the length of the longest tail feather, but since 

 the tail feathers are embedded in the muscle and other tissues of the "pope's- 

 nose " it is necessary to add a little to the actual visible length of the longest 

 tail feather. Hence it is customary to feel for the root of the tail, place one 

 leg of the compasses in the center of the pope's-nose, and extend the other 

 leg of the compasses to the end of the longest feather, the distance thus 

 obtained being the length of the tail. Third, length of bill. Usually this 

 means the same as length of culmen, the culmen being the profile or upper 

 outline of the bill, and its length is obtained with the comjiasses by taking 

 the distance in a straight line from the tip of the bill to the point where the 

 ridge of the upper mandible meets the feathers of the forehead. This is really 

 the chord of the culmen. In long-billed birds like snipe and sandpipers, 

 which have little gape, this measurement is very nearly the same as the length 

 of the bill, but in sparrows, hawks, swallows and a host of other birds, the 

 measurement from the tip of the bill to the corner of the mouth would be very 

 different from the length of culmen obtained as above Fourth, length of 

 tarsus or simply "tarsus." The tarsus of course is the shank, or what is 

 loosely spoken of as the leg, and the measurement sought is the distance 

 from the heel joint (wrongly called the knee) to the junction between the 

 shank and the foot proper. This measurement should always be taken 

 with the compasses and on the front of the shank, one point being placed at 

 the junction between the upper leg, or tibia, and the shank, or tarsus, while 

 the other point should reach the suture or crease which separates the shank 

 from the root of the toes. When the legs are long and naked this measure- 

 ment can be taken quickly and accurately ; if the legs are more or less feathered 

 the measurement becomes somewhat less definite, but on the whole the length 

 of tarsus is one of the most important data used in bird identification. Ref- 

 erence to the various figures of bill, foot and wings, scattered through the 

 text, will make still more clear the preceding directions. 



Of course other measurements are frequently called for, some of those 

 in most general use being the length of the toes, either with or without the 

 claws or nails, and it is probably safe to caution the beginner not to confound 

 the toes with the claws. The claw^ or nail forms the terminal segment of each 

 toe, and its length is of course a totally different thing from that of the entire 

 toe. A bird's foot as a rule has four toes and these are most often arranged 

 with three pointing forward and one backward, the latter consequently 

 being called the "hind toe." It is also spoken of as the "first toe," while the 

 front toes are numbered respectively 2, 3 and 4, number 2 being the inner 

 toe, number 3 the middle toe and number 4 the outer toe. In most birds 

 which run freely on the ground and seldom use the feet for grasping a perch 

 or other object, the hind toe is apt to be somewhat elevated above the level 

 of the front toes and it may be quite short or even entirely wanting. In some 

 other birds two toes point forward and two backward, this arrangement 

 being known as yoke-toed, and as a rule it is the outer or fourth toe which 

 is turned backward, although there are cases in which the inner or second 

 toe takes this position. 



The nomenclature of the wings, including the primaries, secondaries, 

 tertiaries, greater, middle and lesser coverts, etc., etc., will be best learned 

 by referring to Plate I and the various text figures. It should be noted, 

 however, that the primaries are always nine or ten and are numbered from 

 the tip or free border of the wing toward the bod}^ number one being the 

 3 



