PETRELS. 42] 



rudimentary or entirely wanting. The structure of the bill serves 

 to distinguish- them from the family of the Gulls, which they re- 

 semble in general form. The apical portion of both mandibles 

 is distinct, separate from the basal part, and the upper surface of 

 the base of the upper mandible is usually occupied by a pair of 

 tubes, generally united together, at the extremity of which are 

 the openings of the nostrils. The nostrils are always of a tubular 

 form. These birds are strictly oceanic in their habits, passing 

 nearly their whole time in flying over the sea, and even apparently 

 delighting in rough weather. Few of them ever visit the shore 

 except for the purpose of breeding, when they deposit their eggs 

 and rear their young in holes or upon the ledges of the rocks. 

 Their food consists of fishes and other marine creatures, together 

 with fragments of animal matter that they find floating on the 

 waves. 



This family comprehends the Petrels proper and the Alba- 

 trosses. 



Sub-Family I. 



THE PETRELS PROPER. PROCELLARIN.^. 



General Characteristics. — Nostrils placed on the basal portion of the culmen, 

 tubular, and generally opened in front. 



These birds live in the higher latitudes of both hemispheres 

 during the summer, and, as the winter approaches, migrate in 

 numerous flocks to the more temperate seas. Their flight is 

 usually rapid and continuous, or performed in graceful curves near 

 the surface of the ocean, where they seek fishes and other marine 

 animals, on which they prey. It is indeed an interesting sight to 

 observe these little birds in a gale, coursing over the waves, down 

 the declivities, and up the steep ascents of the foaming surf, that 

 threatens to burst over their heads ; sweeping along the hollow 

 troughs of the sea, as in a sheltered valley, and again mounting 

 with the rising billow, occasionally dropping their feet and striking 

 the water, and sometimes leaping, with both legs parallel, on the 

 surface of the roughest waves for several yards at a time. When 

 any greasy matter is thrown overboard from a ship, the Petrels 

 instantly collect around it, facing to windward, with their long 

 wings expanded and their webbed feet patting the water. In 



