THE BIRDS. 



205 



lower edge of the bill extending from the angle of the chin 

 to the tip is called the yonys, the crest of the upper jaw the 

 culmen, and the region between the eye and the base of 

 the beak (which in the birds of prey is covered by the 

 cere) is called the lore. (Fig. 211.) 



While the beaks of most birds are slender or stout and 

 conical, as in the loon, those of the ducks and geese are 

 broad and lamellate, adapted for sifting 

 shells and worms from soft mud; those 

 of the curlew, snipe, woodcock, and 

 avoset, as well as the humming-bird, are 

 remarkably long and slender, sometimes 

 upcurved, and adapted for boring into 

 the mud and turning over small stones for 

 worms. The hen's beak is for picking up 

 seeds, while the eagle's is for tearing the 

 flesh of its prey, and the sparrow's (or coni- 

 rostral) beak is adapted for separating 

 seeds from their husks or for opening 

 buds. More extreme examples are the fH 

 auk's bill, by which it can peck out a tun- 

 nel in hard soil or even soft rock, or the FlG - i5.-Fiamingo. 

 flamingo's, whose under jaw forms a cover for the upper 

 while drinking (Fig. 215), or the voracious pelican's, whose 

 enormous bill and naked, distensible throat enables it to 

 scoop up and swallow a shoal of fish at a time. 



Since the food, whether small fish, shells, or seeds, is 

 swallowed whole by the bird, it must be crushed and com- 

 minuted before it can be digested; hence the hinder end of 

 the stomach is enlarged and forms a gizzard. The walls of 

 the gizzard are, in the seed-eating birds, such as the hen, 

 very thick and muscular; and on the inner surfaces are two 

 solid, horny plates, which act like an upper and nether 

 millstone to crush hard seeds. In the fowls, pigeons, and 

 parrots the throat dilates on one side into a round crop in 

 which the food is softened before it passes on to the gizzard 

 to be finally crushed. 



