32 THE ARCHITECTURE OF BIRDS. 



rough mattress the female eider spreads a bed of 

 the finest down plucked from her own breast, and 

 by no means sparingly, but, as Brunnich informs us, 

 heaping it up, so as to form a thick puffed roll quite 

 round the nest. When she is compelled to go in 

 quest of food after beginning to sit, she carefully 

 turns this marginal roll of down over the eggs to 

 keep them warm till her return. It is worthy of re- 

 mark, that though the eider-duck lays only five or six 

 eggs, " it is not uncommon to find more than even 

 ten and upward in the same nest occupied by two 

 females which live together in perfect concord ;"* 

 a circumstance, however, of which we shall meet 

 with other instances as we proceed. 



The quantity of down in each nest is said by Van 

 Troil to be about half a pound, which, by cleaning, 

 is reduced one half. By Pennant, who examined the 

 eiders' nests in the Farn islands, off Northumberland, 

 it is only estimated, when cleaned, at three quarters 

 of an ounce, and this was so elastic as to fill the crown 

 of the largest hat.f The difference of quantity in 

 these two accounts, theoretically ascribed by the 

 translators of Buffon to difference of climate, may 

 have arisen from the one being the first, and the 

 other the second or third nest of the mother duck : 

 for if the first nest be plundered of its down, though 

 she immediately builds a second, she cannot furnish 

 it with the same quantity as before ; and, if forced 

 to build a third time, having then stripped her breast 

 of all she could spare, the male is said to furnish 

 what is wanting, which is recognised as being con- 

 siderably whiter than the female's. When the nest 

 is not robbed, it is said that he furnishes none. 



The extraordinary elasticity of the down appears 

 from the fact we have mentioned of three quarters 

 of an ounce filling a large hat. It is worthy of no- 

 tice, however, that it is only the down taken from 



* Van Troll's Letters on Iceland. 



t Pennant, Tour in Scotland, 8vo. edit., p. 36. 



