100 THE STORY OF BIRD-LIFE. 



ciently extraordinary structure to deserve a brief 

 description here. It is a long thin-walled bag 

 running all the way down the neck, just under the 

 skin. Its upper end opens in front of, and below 

 the tongue, its lower end is often flask-shaped 

 enabling it the more easily, at the constricted 

 portion, to pass between the merry-thought. 

 When the bird is "showing-off" this pouch is 

 filled with air, and thus increases the size of the 

 neck enormously. This pouch was believed by 

 the older ornithologists to be for the purpose of 

 holding water, owing to the difficulty of pro- 

 curing this in the arid localities in which the 

 birds lived. But as the pouch is only present 

 in the male the force of this argument was hard 

 to see. 



The display of the pinnated grouse {Tym- 

 jpanuchus Americanus) has been vividly described 

 as follows by Captain Bendire : *' Early in the 

 morning you may see them assemble in parties, 

 from a dozen to fifty together, on some high dry 

 knolls where the grass is short, and their goings- 

 on would make you laugh. The cock birds have 

 a loose patch of naked yellow skin on each side of 

 the neck just below the head, and above these on 

 either side, just where the head joins the neck, 

 are a few long black feathers which ordinarily 

 lay backward on the neck, but which, when 

 excited, they can pitch straight forward. Those 

 naked yellow patches . . . cover sacs which they 

 can blow up like a bladder whenever they 

 choose. These are their ornaments, which they 

 display to the best advantage before the gentler 

 sex at these love-feasts. This they do by blowing 



