LIFE HISTORIES OF NORTH AMERICAN PETRELS AND PELICANS. 87 



excavations were in peaty ground over which a fire had passed, destroying 

 all surface vegetation. The young at this time were half-grown, covered with 

 light grey down, and extremely fat. On heing held up by the feet, oily matter 

 ran freely from their throats. The old birds, on being taken hold of, fought 

 fiercely with their bills. 



There are some nesting grounds of this species on Whale Island on the Bay 

 of Plenty. I visited these breeding places about the middle of January and 

 found the nestlings still occupying their deep burrows, but they were well 

 grown, with black quills and tail feathers sprouting vigorously through their 

 thick downy mantle of slate grey. 



Probabl}', as is the case with nearly all of this genus, the young 

 bird passes from the downy stage directly into a plumage resembling 

 the adult. Apparently there is only one complete annual molt long 

 after the close of the breeding season or during our summer. 



Food. — Capt. J. W. Collins (1884) says in regard to their food: 



From my observations I am of the opinion that the hag subsists chiefly on 

 squid, which, of course, it catches at or near the surface of the water. I have 

 opened many hundreds of them and have never, to my recollection, failed to 

 find in their stomachs either portions of the squid, or, at least, squid's bills. 

 It may be interesting also to mention the fact that in the fall of 1875, when 

 the giant Cephalopods, or " big squid," were found on the eastern part of the 

 Grand Bank between the parallels 44° and 45° north latitude, and the meri- 

 dians of 49° 30' and 50° 30' west longitude, flocks of hagdons were invariably 

 found feeding on the dead " devil fish " which were floating on the water. In 

 nearly all cases these " big squid " were found in a mutilated condition, usually 

 with their tentacles eaten ofE almost to their heads, and the fishermen soon 

 learned to detect their presence by the large flocks of birds collected about 

 them. The small species of fish which frequent the waters of the eastern 

 fishing banks, such as the lant, capelin, etc., also furnish Puffinus with a por- 

 tion of its food. But birds of this species, as well as most all others found at 

 sea, are excessively fond of oily food, and especially the livers of the Gadidae, 

 cod, hake, etc., and this extreme fondness for codfish livers, Avhich they swal- 

 low with great avidity, renders their capture possible bj' the fishermen with 

 hook and line. 



Behavior. — The flight of the sooty shearwater is swift, graceful, 

 and strong; like other species of Pu^nus, it can sail for long dis- 

 tances on its long, stiff wings without even a tremor, except to ad- 

 just them slightly to the wind, rising at will over the crests of the 

 waves or gliding down into the valleys between them and turjiing 

 as the albatrosses do by lowering the wing on the inner side of the 

 curve and raising the wing on the outer side, both being held in a 

 straight line, the angle of incline depending on the sharpness of the 

 curve. It frequently flaps its wings, however, when occasion re- 

 quires it and uses them freely in its squabbles for food. It some- 

 times experiences a little difficulty in rising from the water in calm 

 weather, but or'dinarily it does so very readily. It swims lightlj' 

 and swiftly on the surface and dives below it occasionally in pur- 

 suit of food, using its wings freely under water. It has frequently 

 been caught on the trawl hooks of the cod fishermen. 



