SEA-BIRD NUMBERS AND MAN IO7 



on the British coast alone. Fig. i8, (opposite) shows the spread of the 

 fulmar in Britain: before 1878 it was known to nest only on St. Kilda. 



Fulmars congregate round trawlers in enormous numbers, up to 

 more than five thousand at one time. Probably every trawler operating 

 within a few hundred miles of a fulmar colony is visited. Almost 

 invariably, the fulmars outnumber any other kind of bird present 

 at hauhng or gutting times. They greedily devour the loose dead 

 fish and bits of fish that come up with the cod end, as well as 

 the guts that are thrown overboard — especially the livers, which are 

 grabbed first. In many parts of the North Atlantic from May to 

 October they are often accompanied by a minority of Tristan great 

 shearwaters and sooty shearwaters. 



Man has one entirely malignant effect on sea-bird populations. 

 He casts crude or waste oil into the sea. This oil of course floats on 

 the surface of the water, and a relatively small amount of oil can 

 form a thin film covering some square miles. The volatile oils evaporate, 

 leaving an asphaltic residue which is sticky. When sea-birds swim 

 or dive through this, they quickly get their feathers matted. 

 This reduces the surface tension of the plumage, and the subcutaneous 

 air spaces, to which the birds owe most of their insulation and much of 

 their buoyancy, are filled with oily water. In cold weather the birds 

 rapidly; lose heat, which they are unable to replace by hunting and 

 feeding. Most of them die. The oil menace particularly aff'ects the 

 surface swimming guillemots and razorbills, which do most of their 

 feeding over the Continental Shelf, and often close to shipping routes. 

 Puffins and gannets also suffer, but not quite to the same extent. 

 For many years this question of oihng has exercised the bird protection 

 societies, and there have been many international meetings and dis- 

 cussions about it. In 1926, for instance, the United States government 

 was host to an international conference in Washington, but at this 

 there was a division of opinion as to what should be done, and all 

 that resulted was a recommendation that oil should not be discharged 

 within fifty miles from land. Some governments, it is true, passed 

 this recommendation to their shipping companies and navies, and, 

 in some cases, the recommendation was even acted upon, but there 

 was no noticeable diminution in the number of cases of oiling, and 

 during the late thirties and the forties, particularly during the war, 

 oihng has been worse than it has ever been, at least round the coast 

 of Britain. There is no question but that sometimes the waste of sea-bird 

 life through oil pollution is substantial. It is also, of course, a common- 



