ST. KILDA AND ITS BIRDS. 867 



throwing his head back. If the sentinel is disposed of 

 all the other sleeping Grannets, which are lying with their 

 heads under their wings, can be seized and killed without 

 difficulty, provided no noise is made. As many as two or 

 three score may thus often be taken one after the other. 

 Frequently, however, the sentinel sees the approaching 

 danger, gives the alarm, and the birds are all off at once. 

 This happens more particularly upon light nights. I 

 endeavoured to form some sort of estimate as to the 

 number of gannets resident in St. Kilda during the 

 summer by ascertaining the number of eggs taken. On 

 May 14th there were taken from the top of Stack Lii (from 

 the summit only) 1,400 fresh eggs ; the great majority of 

 the birds had then laid, but some nests were still 

 unoccupied. Perhaps, then, 1,500 nests might represent 

 the number on the sloping faces on the top of this stack 

 only. But the men say that on the whole of the rest of 

 this stack there are more nests than on the summit, and 

 if this be so, the total number of nests on Stack Lii may 

 perhaps be put at 3,500 to 4,000. On Stack an Armin, 

 though the birds are very numerous, they are appreciably 

 less so than on Stack Lii, and the number of nests may 

 perhaps be put at about 3,000. On the cliffs of Boreray 

 the natives consider that there are more nests than on the 

 two stacks put together, and the number may therefore be 

 approximately reckoned at about 8,000. Doubling the 

 number of nests to get the number of birds, and allowing 

 for a fair sprinkling of non-breeding birds, of which the 

 natives say there are a good many, we get a total of some 

 30,000 birds. This estimate is much less than that given 

 by some writers, and it, of course, does not pretend to be 

 more than a rough calculation. It probably errs on the 

 side of deficiency, but at the same time it has to be borne 

 in mind that 1,000 birds of the size of a Gannet make a 



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