BRITAIN'S BIRDS AND THEIR NESTS. 145 



to be from five to eight in number, but sometimes three or 

 four form the full clutch, and we have rarely found five 

 exceeded (Aberdeenshire). On the other hand, we have seen 

 an Eider-Duck followed by a brood of ten. Whether the 

 number of eggs or nestlings actually found together may 

 always be taken as the proper clutch or brood is doubtful, 

 if we are to accept the statement of one writer that the 

 Eider-Duck habitually steals both eggs and young from 

 others of her kind. A case has been related in which an 

 Eider-Duck had her own eggs sucked by a Lesser Black- 

 backed Gull, and thereupon appropriated the Gull's nest 

 and eggs in place of her own. We have known of an 

 Eider-Duck's egg being found in a Black-headed Gull's 

 nest along with two eggs of the rightful owner — one of 

 them broken. A satisfactory explanation of this case was 

 not forthcoming;. 



The nest itself, when laying begins, is merely a hollow 

 in the groimd with or without a lining of bent-grass, sea- 

 weed, or other material; but during incubation the eider- 

 down is added, and most of it placed round the outer edge 

 of the nest ready to be pulled over the top of the eggs 

 when the mother leaves to find food for herself. Bent- 

 grass is sometimes used to cover the eggs as well as to 

 line the nest, but probably only in the earlier stages 

 of incubation. When disturbed, the duck has not time to 

 cover her eggs; but as she rises she squirts— sometimes 

 with a none too accurate aim — an evil-smelling, oily liquid 

 over them. In the later days of incubation especially she 

 is an exceedingly close sitter, and will often allow herself to 

 be touched without showing any signs of fear. In the 

 northern countries, where she is carefully protected for the 

 sake of her down, she is extraordinarily tame, and habitually 

 nests inside inhabited houses — in the oven — willingly sur- 

 rendered — for instance. In this country low islets are 



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