CHAPTER I 



THE NORTH ATLANTIC OCEAN 

 ITS STRUCTURE AND ITS SEA-BIRDS 



THE Atlantic Ocean is a big broad blind alley, kinked like a 

 zig-zag, its jagged north end blocked with ice, its broader south 

 butt cornered by the cold stormy narrow eastern entrance to the 

 Pacific Ocean, and by the warm, windy and wide western gate to the 

 Indian Ocean. It resembles two wedges, their apexes towards the 

 North Pole, one of them truncated midway and at that point connected 

 sideways to the base of the other. 



The birds inhabiting the more northerly of these wedges, the 

 North Atlantic, are the birds of this book. Two of these birds have 

 become extinct in historical times: the great auk was never seen alive 

 after 4 June, 1844, and the last Labrador duck was shot in 1875, 

 though some say one was shot in 1878. The number of living species 

 that remain is about one hundred and eighteen, of which eighty-six 

 have been seen on the western seaboard of Europe (which includes 

 Iceland), and ninety-three on the eastern seaboard of the New World 

 (including Greenland). 



However, for an understanding of the environment to which the 

 North Atlantic birds are adapted, a description of the whole ocean is 

 necessary, and to this we must proceed. 



The extremely simple fundamental shape of the Atlantic invites 

 diagrammatic caricature (fig. i, p. 3). It is the second largest ocean in the 

 world. It is, on an average, over two and a quarter miles deep, and 

 in some places nearly six. It is, on an average, three thousand five 

 hundred miles across (maximum about five thousand) ; and is nine 

 thousand miles long. Its area has been estimated as thirty-three 

 million square miles, and its volume as seventy-five million cubic 

 miles. It is a vast place, with many miles of coast, upon which much 

 of civilization depends: considering its size, it has few islands. In 



