64 SEA-BIRDS 



the polar creeping willow; and tufted, drooping, alpine brook saxi- 

 frages; and the alternate-leaved golden saxifrage; and alpine mouse- 

 ear chickweed, various arctic whitlow-grasses, poas and a woodrush, 

 and IVahlbergella; and sometimes carpets of Jacob's ladder. There 

 are many mosses, too, with bright colours; and all over these arctic 

 cliffs — not only below the bird ledges — grow lichens. One of them 

 is the beautiful orange Caloplaca elegans; it grows all over the bird 

 rocks of Spitsbergen, shines yellow orange among the dark rock and 

 green grass-ledges of the fulmar-haunted bastions of Disko in West 

 Greenland, and colours from top to bottom the mighty buttresses of 

 Cape Searle in eastern Baffin Island, the site of what may be the world's 

 largest fulmar colony. Grey fulmars sit on green ledges above orange 

 rocks. 



In Britain, St. Kilda is the greatest sea-bird station. Upon its 

 thousand-foot precipices nests one of the densest communities of 

 vertebrate animals in the North Atlantic — probably the densest 

 south of the Arctic Circle. The gannets of Boreray and its stacks have 

 about seventeen thousand nests — one-sixth of the world population 

 of this species. A quarter of Britain's fulmars (up to forty thousand 

 pairs) nest on St. Kilda. Undoubtedly more than a million puffins' 

 eggs are laid on St. Kilda in a normal year; the question is, how many 

 million? There are seven separate puffin-slopes on St. Kilda each of 

 which is larger than the largest puffin colony anywhere else in the 

 British Isles, even the largest puffinry in the mossy talus-slopes of the 

 Shiant Isles, where blocks of columnar basalt lie below the cliffs 

 like the forgotten bricks of a child. The puffin is certainly one of the 

 most numerous birds in the North Atlantic. In his monograph on the 

 puffin (1953) Lockley estimates a minimum world population of 

 15,000,000 adults. 



•t* *J* T* 



From the study of the ecology of animals we are learning that their 

 numbers are controlled primarily by the amount of food they can 

 get, and only secondarily by their parasites and predators; and 

 parasites are probably more important than predators. But there 

 are exceptions to this; and the chief one is when the predator is man 

 (another is when new predators are introduced through his agency). 

 Except in a few places such as most of Greenland, Jan Alayen, Spits- 

 bergen, Franz Josef Land and a few other arctic islands, man is, 

 or has been, the most important predator of sea-birds. He has been 



