l84 



Bird -Lore 



Fig. 4. Forearm of the 

 African Jacana 



birds are fouiui in the Uniretl States, and most of them, as indicated above, 

 come from southern latitudes, one of the larj^est and finest being the 

 Chilean Plover [Belonopterus chilensis). The spur is situated just at the 

 base of the thumb and, like the spurs on 

 the legs of other birds, consists of a sheath 

 of horn fitting closely over a core of bone 

 (Fig. 2). Some of the spur-winged Plov- 

 ers have fleshy wattles about the face, whence 

 the names Lobivanellus (Fig. 3), lobed- 

 plover. and Sarciophorus, flesh -bearer; and 

 there is a curious relation between the size of the spur and the size 

 of the wattle, for when one is large the other is correspondingly well 

 developed, and when the wattle is small the spur also is small. No such 

 relation as this exists between the spurs and wattles of domesticated fowls, 

 but in their case selection has been artificial and not natural, so the 

 instances are not similar. 



The pretty little Jacanas are among the spur -winged birds, and it is ap- 

 parent from the length and slenderness of the toes that spurs upon the legs 



would be of little or no use for 

 the birds would probably not be 

 a success as kickers. Now there 

 is a group of Jacanas peculiar to 

 Africa which have no spurs on 

 their wings, and these present a 

 curious modification of the radius, or outer bone of the forearm (Fig. 4), 

 so that this may serve instead. The bone is flattened and widened until 

 it somewhat resembles an Australian throwing -stick in miniature and pro- 

 jects so far beyond the edge of the wing that it makes a very effective little 

 weapon with which to buffet an adversary about the ears. There seems 

 to be, however, one disadvantage about this arrangement; that is, the 

 blow ought to hurt the bird by which is delivered about as much as the 

 one by which it is received, 



but if birds are like unfeathered 



bipeds there would be much 



consolation in knowing that 



the more one smarts the worse 



is the opponent punished.- 

 The Spur winged Goose, 



Plectropterus ^amhensis, shows a 



variation in the making of a weapon by having the spur on one of the wrist 



bones instead of on the metacarpus (Fig. 5), where it is usually placed. 



but this only serves to show that nature is not bound to an\ hard and fast 



method of equipment. 



Fig. 5. Part uf the wing of the Spur-winged Goose 



Fig. 6. The liouhle spur of the Sc.-eame 



