206 The Field Naturalist 's Quarterly August 



I rescued five unincubated eggs of the loon from a taxi- 

 dermist's shop, and put them into three coots' nests. Within 

 two days every one of these grebes' eggs were sucked — pre- 

 sumably by crows — whilst numerous nests full of coots' eggs 

 were left unharmed near by. The slight difference in the 

 ground colour, and the absence of the small black markings 

 were apparently sufficient to attract the leery eyes of the 

 prowling Corvidae. I have found a wild duck and a short- 

 eared owl nesting within a few yards of one another : whence 

 is the necessity for the great difference between the procreant 

 cradles of these two ground builders ? True, the species are 

 widely divided, and their whole domestic economy is differ- 

 ent, but here we see that the warmth and depth of a bird's 

 nest is not always dependent either upon the state of the 

 young when hatched or upon the duration of time they 

 subsequently remain in the nest, for the offspring of the 

 former are nidifugous, those of the latter nidicolous. Nor is 

 the concealment of the duck's eggs by her down when she 

 leaves the nest necessitated by the greater conspicuousness 

 of her eggs, for the pure white eggs of the owl are far more 

 visible at a distance. What, then, is the utility of the down- 

 covering, and how is it that this species of owl still exists, in 

 spite of its laying a white egg in an open nest ? The owls 

 are night-feeders, and the male bird also feeds the female on 

 the nest by day, so that she can conceal her eggs and retain 

 her feathers on her breast whilst doing so ; whereas the 

 mallard does not thus attend to the wants of his spouse, 

 but she is obliged to cater for herself and to seek her food 

 at some distance from her eggs, and that frequently whilst 

 swimming or paddling in the water. The down-covering, 

 therefore, assists in retaining the warmth of the eggs whilst 

 she is away, and also lessens the chance of their being chilled 

 on her return from contact with her wet plumage. 



In his grand work on the surface-feeding ducks J. G. 

 Millais mentions having frequently found nests of the 

 mallard, when placed near the water, unfilled with down ; 

 one can only imagine that frequent robbing of the eggs, and 

 the consequent building of extra nests resulted in a deficiency 

 of down to line them with, as the eider duck "farmers" have 

 found to be the case. Such a departure from the ordinary 



