84 BIRDS' NESTS 



is provided, until the never-failing carpet of down is 

 added. The more or less speckled appearance of this 

 down makes a fully completed Duck's nest look very 

 pretty, and more especially so when, as is often the 

 case, it is well mixed with the bright-hued vegetable 

 fragments that go to form the remainder. Naturalists 

 are by no means agreed upon the precise use of this 

 down in the nesting economy of the Ducks, some 

 maintaining that it is placed there for purposes of 

 warmth, being an admirable non-conductor of heat. 

 Others incline to the opinion that it serves to conceal 

 the eggs from enemies, the sitting Duck being careful 

 to cover these with a downy coverlet when leaving 

 them for a time. I incline to the latter belief, not 

 only because Ducks breeding in the warmest countries 

 of the world, where extra heat is unnecessary, still 

 surround their eggs with down, whilst other species 

 breeding in the same localities, almost side by side, 

 require no such supplementary warmth, or are even 

 nestless, but because I have seen so many instances 

 where the hidden eggs have been most effectually 

 concealed by the harmony of their covering with sur- 

 rounding objects. It may be worthy of remark that 

 the species nesting in covered sites, in burrows or in 

 holes of trees and so forth, have the down pale and 

 conspicuous — a fact which would only lead to the 

 discovery of the nest were it built in a more exposed 

 or open site. The nests of some of the Geese are 

 quite as crude as those of the Ducks already men- 



