230 BILLS OF SKIMMING BIBDS. 



The true scavenger's bill on the "high seas" is 

 that of the petrels, of which the fulmar's is typical. 



The angular portion at the tip of the upper man- 

 dible of this bill, and the bend on the lower, which 

 acts against it, are both very strong and hard, so that 

 it is well adapted for tearing the flesh of whales and 

 of the larger fishes when their carcasses float dead on 

 the sea. By that most efficient part of the bill being 

 carried at an oblique angle to the water, while the 

 bird swims or skims the surface, it can easily pick up 

 all manner of garbage, however minutely divided, 

 and even sip the oil which floats on the sea. 



The numbers of these petrels are immense, far 

 greater than those of any other birds a single flock 

 is sometimes seen as numerous as would cover the 

 surface of a county. They afford a very striking 

 instance of the vast productiveness of the sea; for 

 they, numerous as they are, are only one of the races 

 that subsist on its refuse. But when we consider that 

 the sea is more than twice as extensive in surface as 

 the land, and that it is inhabited to the depth of many 

 fathoms, while the land can (as the barren places com- 

 pensate for the elevations, whether of hills or of ve- 

 getables) be reckoned only as the one surface, we are 

 within the limits when we say that the productive 

 power of the sea is a thousand times greater than 

 that of the land ; or that, if its productions could be 

 arrived at, and their nature would suit, the sea might 

 support all the life that could exist upon the land, and 

 never feel the burden. 



The storm-petrels are lighter birds, and of more 

 rapid wing than the common petrels ; but they have 

 the bill of the same form, though weaker. They sub- 

 sist chiefly upon the smaller garbage, and especially 

 upon oil, which they collect from the water on the 



