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 happily 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 
