HTJTTON ON THE BIRDS OP THE SOUTHERN OCEAN. 239 



Most of the Petrels, more particularly those that "burrow, or live in 

 holes in rocks, are, no doubt., nocturnal in their habits when they are on 

 or near land ; but when they are at sea, they all become more diurnal. 

 A few can certainly be often seen flying under the stern at night; and 

 once, when I was keeping the middle watch, at about one a. m., a Cape 

 Pigeon, in crossing over the ship, struck a rope, and fell on deck. Still 

 they are never numerous, and where there were fifty or a hundred birds 

 in the daytime there are only one or two at night. Their defenceless 

 condition is, as far as i can see, the only reason for the Petrels hiding 

 themselves by day, and flying by night ; for the oceanic mollusca, &c, 

 on which they feed, are equally diurnal and nocturnal. At sea, however, 

 where they have no enemies to fear, and no holes to hide in, the condi- 

 tions are quite different, and it is then better for them to take their rest 

 at night, and to be alert and feeding in the daytime, and they change 

 their habits accordingly. I therefore believe that, although a few may 

 follow a ship for a night, most of them sleep on the sea; and in the 

 morning, knowing very well that a ship is the most likely place to ob- 

 tain food, they fly high with the intention of looking for one. Some 

 find the ship that they were with the day before ; some another one. In 

 the latter case, if the second ship is going in an opposite direction to 

 the first, they are never seen by the first again ; if, however, the course 

 of the two ships is the same, the bird might very likely lose the second 

 ship, and rejoin the first after a lapse of two or three days. A height 

 of 1000 feet would enable a bird to see a ship 200 feet high more than 

 fifty miles off; and often, although unable to see a ship itself, it would 

 see another bird which had evidently discovered one, and would follow 

 it in the same way that vultures are known to follow one another. 

 This opinion is much strengthened by the fact, that at sunrise very few 

 birds are round the ship, but soon afterwards they began to arrive in 

 large numbers, and I think I may safely say that this is always the 

 case ; for, having had to be on deck from four to eight o'clock every third 

 morning for six of my voyages, and about once a week during my last 

 voyage, I have had better opportunities for observing this than most 

 people. Sir J. Herschel states, in his "Physical Geography," p. 347, 

 that the Albatross sleeps on the wing ; but, to the best of my knowledge, 

 no one has seen this, and it appears to me to be quite impossible ; for, 

 as I shall presently show, the bird cannot sustain itself in the air unless 

 it has an onward movement ; and if this movement was given by the 

 wings, sleep would be no rest to it. 



The unrivalled flight of the Albatross has been the admiration of 

 voyagers from the earliest time. Day after day, with unabated inte- 

 rest, I have watched them, and I quite agree with Mr. Gould that the 

 Sooty Albatross {D.fuliginosa) carries off the palm from all competitors. 

 Never have I seen anything to equal the ease and grace of this bird as 

 he sweeps past, often within a few yards, every part of his body per- 

 fectly motionless except the head and eye, which turn slowly, and 

 seem to take notice of everything. I have sometimes watched narrowly 



