20 ANNALS OF SCOTTISH NATURAL HISTORY 



BIRD-LIFE AS OBSERVED AT SKERRYVORE 



LIGHTHOUSE. 



By JAMES TOMISON, Principal Light-Keeper. 



SKERRYVORE LIGHTHOUSE is situated on a small reef in 

 North Lat. 56 19' 22" and West Long. f 6' 32"; n 

 nautical miles W.S.W. ^- W. of the island of Tiree, the 

 nearest land ; 33 miles S. \ E. of Barrahead, the southern- 

 most point of the Outer Hebrides; 30 miles W. of lona; and 

 50 miles from the nearest point of the mainland of Scotland. 

 From Hynish Point in Tiree to the Mackenzie Rock 3 

 miles W.S.W. of Skerryvore there is a continuation of 

 " foul " ground consisting of small rocks, some above sea- 

 level, others covered at high water, and others constantly 

 under water, but near enough the surface to be a source of 

 the greatest danger to the mariner who unwittingly comes 

 in their vicinity. There is thus stretching right out in the 

 Atlantic, in the fairway of all shipping passing through the 

 Outer Minch, as dangerous a line of reefs and shoals as can 

 be found anywhere round our coasts. The Skerryvore, or 

 Big Skerry, was selected as the most suitable on which to 

 erect a lighthouse, owing to it being always above water, 

 and being of some considerable extent, affording fair facilities 

 for landing. The superficial area of this rock at low water 

 is about 300 sq. ft., and less than half that size at high 

 water. The rock itself consists of quartz, felspar, hornblende, 

 and mica, and is extremely hard, so that where it is polished 

 by the action of the sea it is quite smooth and slippery, and 

 landing on it has been described as " like climbing up the 

 neck of a bottle." A trap rock in the form of a dyke of 

 basalt intersects the strata, and lies almost due North and 

 South, being continuous until lost in the sea at either end, 

 a distance of 150 feet. The building of the lighthouse was 

 begun in 1838, and after six years of arduous labour was 

 completed, and the light first exhibited on ist Feb. 1844. 

 It has now withstood the force of the Atlantic storms and 

 billows for over sixty years, and to-day shows not the slightest 

 signs of decay. 



From an ornithological point of view it is a place of 



