48 The Bird 



pelled to undergo the fall moult in a rather small body 

 of water, where danger menaces on all sides. Although 

 when flightless he swims low among the thick water-reeds, 

 yet his brilliant colours — iridescent green and white — 

 would too frequently mark him out. So the invisible 

 cloak of his brooding mate is dropped over him for a 

 while — his colours vanish, and by a partial moult thus 

 sandwiched in, the hues of his plumage change to an 

 inconspicuous mottling of brown, hardly distinguishable 

 from the female. Then when the splitting of his quill- 

 sheaths hints of coming power to take care of himself 

 again, the dusky mantle is lifted, and, triumphantly 

 treading water, he stands upright and shakes his glisten- 

 ing wings, daring his enemies to catch him if they can. 

 This has been happih' termed the ''eclipse" plumage. In 

 certain portions of the Old World where foxes are scarce 

 and the ducks have been persistently pursued by men 

 in boats, the knowing birds have changed their habits 

 and, when their wing-quills fall, they make their home 

 in deep woods, finding greater safety there than on ponds 

 or lakes. 



A somewhat similar condition occurs in the Black 

 Grouse of Europe, which loses the conspicuous black 

 feathers of the head and neck during the helpless period 

 caused by the moult of its tail-feathers. 



This additional moult brings us to the consideration 

 of the birds which have no less than three changes of 

 plumage, and here we find the cause intimately connected 

 with the colour of the birds' surroundings. Ptarmigans, 

 which are species of grouse living in the far North, moult 



