THE PENTLAND SKEBRJES. 



ALTHOUGH we have described these islands in a former work, 1 still 

 they really belong to the Orkneys, being included in the parish of 

 S. Eonaldsay. In any case, however, a book on the Orkney avi- 

 fauna would be incomplete without a mention of these well-known 

 " Skerries." Lying as they do in the course of one of the most 

 famous migration lines in Scotland, many birds occur there almost 

 commonly, which, as visitants to the islands themselves, are 

 decidedly rare ; and it may well be, that owing to the attraction of 

 these lights, Orkney is indebted for many records of the rarer 

 species, which, without this attraction, would pass on. Other 

 lighthouses there are in Orkney, which have contributed their 

 quota to the Migration Eeports issued for several years back by 

 the committee formed for collecting these facts ; but the Pentland 

 Skerries are facile princeps, being, we believe, scarcely second in 

 importance to the Isle of May in the Firth of Forth. 



We hope from this, however, our readers will quite understand 

 that it is not from the mere fact of there being lights on the 

 Skerries that birds are drawn out of their line of flight by them, 

 or that such lights placed vaguely anywhere would give such 

 good results ; it is because these lights are in the course of the 

 main fly-line over Orkney, which line is concentrated by the cliffs 

 on each side of the Pentland Firth, that we have such wonderful 

 results. 



To go into the whole general subject of migration is not 

 necessary here ; there is quite enough to be said about the area 

 under consideration. 



1 A Vertebrate Fauna of Sutherland, Caithness, and West Gromarty, 8vo, 1887. 



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