i8o THE SCOTTISH NATURALIST 



sitting on a Herring Gull's egg! There was no doubt about 

 it, as the egg reeked of Fulmar. She returned to it as soon 

 as I walked away. 



I saw a pair of Whimbrels on the high ground, but had 

 not time to search for a nest. 



There were four colonies of Arctic Terns, and many 

 Eider Ducks nesting; and, in addition to the cliff-breeding 

 birds, Wheatears and Starlings (nesting in the walls), 

 Hooded Crows, Rock-pipits, and Oyster-catchers were seen. 

 Amongst the Terns I noticed one in the rarely observed 

 plumage of the year-old bird, i.e., with the white forehead and 

 mottled crown of head. 



Leaving Rona, I again visited Stack, but though the sea 

 was very smooth, there was far more swell than at my last 

 visit, and landing was out of the question. However, I steamed 

 close round the skerry and took another careful survey of the 

 number of Gannets, and was quite satisfied with my former 

 estimate of 5000. One or two birds were still carrying 

 seaweed to the island. 



I took the temperature of the water at 5 P.M. 5 2 at 10 

 feet, and 51 at 60 feet; and then steamed off towards the 

 Pentland Firth. 



Immediately after leaving the island we came across a 

 number of Great Shearwaters and a few Fork-tailed Petrels. 

 The yacht's engines were slowed down, and for two hours we 

 were passing amongst the Shearwaters. It was difficult to 

 estimate their numbers, for though the sea had an oil)' 

 surface, there was a rather heavy swell, which hid the birds 

 just as one detected them. Many of them were sitting 

 amongst the Guillemots, and, unless the white throat was 

 turned towards me, it was not easy to see them at a distance. 

 Often, however, six or eight were in sight at one moment. 

 As they skim over the water away from one, they look like 

 very dark but slightly slimmer Fulmars, with a dark band 

 across the tail and conspicuous white upper tail-coverts. A 

 side view reveals the white cheeks, which seem to extend 

 almost as a collar behind the nape. At times we glided 

 within thirty or forty yards of one sitting on the water, and 

 in bright sunlight it is seen that they are a lighter brown 



