398 PETRELS AND SHEARWATERS 



They take their name " shearwater " apparently from their peculiar 

 "shearing" method of flight when feeding, during which they 

 alternately rise and descend with the waves with outstretched wings, 

 the descent taking an oblique direction, which is admirably described 

 by the word "shearing." The earlier ornithologists, however, seem 

 not to have observed this peculiarity, and the only species known to 

 them was the Manx or "Manks" shearwater, which Montagu, for 

 example, called the puffin. In his day this bird bred in large colonies 

 in the Isle of Man, where their young were taken during August in 

 great numbers and salted down for food. And the same toll was 

 levied on their numbers in the Orkneys. 



The Shearwaters differ conspicuously from the smaller Petrels, 

 such as the storm and forktailed-petrels on the one hand, and the 

 fulmar on the other, both in the shape of the beak and in the form 

 of the body. These are features which have too long been set aside 

 by the field ornithologist as " structural " characters, and therefore 

 not coming within their purview. This is unfortunate, and the time 

 is now come when the field ornithologist and those of us who are 

 supposed to be more directly concerned with structural characters 

 should join forces, for it is certain that not till then shall we be able 

 to divine the exact relation which undoubtedly obtains between 

 structure and habit. 



Take this very instance of the shape of the beak. In how far has 

 this been determined by the nature of the food ? So far as the 

 evidence goes, these birds display a striking similarity in their choice 

 of food, and nowhere is this more apparent than in the fondness they 

 show for sorrel, which they prefer even to sea-weed. Vegetable 

 matter, however, forms but a small portion of their daily rations, and 

 it is, of course, only procurable during their sojourn on their breeding- 

 grounds, for the rest of the year is spent far out at sea. The ocean 

 is their main source of food, and this seems to be made up of small 

 surface-swimming organisms, especially Crustacea. But among the 

 larger species like the fulmar and the Shearwaters, cuttle-fish seem 



