VALUE OF BIRDS TO MAN. 41 
refuse is voided. ‘Thisis digestion. The food is often manip- 
ulated, crushed, or divided by the beak. It then receives 
saliva from the mouth, and passes through the pharynx into 
either the gullet (a muscular and membranous tube) or crop 
(a pouch), as the case may be, organs capable 
of great distention, and connecting with the 
first division of the stomach. Here, then, 
is the first receptacle of the food. Birds 
of prey, Herons and some other large birds 
sometimes fill the gullet to the very mouth, 
while awaiting the digestion of the food in 
a stomach already full. The Pelicans have 
also another great receptacle or pouch, ex- 
ternal and beneath the beak, where a store 
of food can be carried. Many of the smaller 
birds also are able, after filling the stomach, 
to stow away a still larger supply of food 
in the gullet. The stomach is large, and 
usually capable, by distention, of contain- 
ing a considerable quantity of food. The 
food passes from the gullet or the crop to “Fig. 1'7.— Alimen- 
the proventriculus or glandular portion of — tary canal of Blue. 
. bird, reduced; after 
the stomach. This is where the process Audubon. a,b,gul- 
of digestion begins. Mixed with salivary,  ousesbiietss' 
ingluvial, and proventricular secretions, the gizzard; ¢, f, h, in- 
food next passes to the gizzard or muscular mca agri 
division of the stomach, where the food grist is ground fine. 
Among seed-eating birds the heavy, powerful muscles of 
this portion of the stomach are, with the rough, calloused 
stomach lining, assisted in their work by sand and gravel 
which are swallowed. This mineral matter takes the place 
of teeth in grinding the food. 
In vegetable-feeding birds the intestine is very long and 
much coiled, while the digestive tract is generally shorter 
and simpler in the flesh-eating and fish-eating species. All 
the processes of digestion are remarkably rapid. The sali- 
vary glands, the liver and the pancreas all quickly pour their 
copious secretions into the alimentary canal; the food is 
chylified after impregnation with the biliary and pancreatic 
