ANATOMY AND PHYSIOLOGY OF RED GROUSE 165 



growing plant by the beak of the bird In captivity it is found 

 'necessary to fix the bunches of heather either by tying them 

 to the wire run or by placing a heavy weight upon the roots ; 

 should this precaution be neglected the bird, having no notion 

 whatever of using its feet to steady anything, drags the loose 

 heather all over the ground in unsuccessful efforts to pluck 

 off the tips. 



There is sometimes to be seen quite a free flow of watery 

 saliva from the beak of a feeding bird, and in the mouth of birds 

 killed there is always a certain amount of saliva. This saliva 

 serves to coat the rough hairy heather tip with mucus, and 

 thus to facilitate its passage down the oesophagus or gullet to 

 the crop (PI. xvi.). The food is, of course, swallowed whole 

 but in very small pieces, and there is no mastication. The 

 length of the oesophagus (PI. xvi.) from the pharynx to the 

 proventriculus or first part of the stomach 1 is 5J inches, 

 when the neck is normally outstretched ; but before passing 

 down the whole length of this tube the food finds its way into 

 a thin-walled sac or diverticulum of the resophagus, at a point 

 3 inches from its entrance at the pharynx, and commonly called 

 the " crop " (PI. xvi.). Here the food collects, and remains 

 for a longer or a shorter period according to the rate at which 

 the gizzard can dispose of it. The lower portion of the 

 oesophagus measures 2 inches in length, and the opening of the 

 crop occupies over half an inch of its length. 



The proventriculus (PL xvi.) forming the thick - walled 

 glandular part of the stomach has a cavity of very small 

 dimensions, and a length of f inch. It is lined with large 

 mucous glands having prominent mouths. These secrete a 

 thick, tenacious, opaque white fluid, wherewith ihe morsels of 

 food on their passage from the crop to the gizzard are coated. 



In this respect there is a very great difference between the 

 condition of the food as it leaves the crop, and its condition 

 in the gizzard. In the crop the food is almost invariably dry, 



1 The stomach of a bird is divided into two portions, the proventriculus and the 

 gizzard. 



