238 NATUIIAL HISTORY SOCIETY OF DUBLIN. 



that those species which burrow require a harder beak than the Sand- 

 martin, or that those species which throw up mounds require one 

 stronger or more sharply curved than the Flamingo ; and it is certain 

 that for the capture of their prey the hooked point is no more wanted in 

 the Petrels than in the Kingfishers, Herons, Divers, &c, and not so 

 much so as in the Gulls (Larus), some of which occasionally kill and 

 devour small birds. This opinion is further strengthened by the fact 

 that the young P. gigantea very much resembles in plumage the young 

 L. catarrhactes, and it also inherits its habit of chasing other birds. 



It is well known that all crepuscular birds have some organ more 

 highly developed than usual, in order to compensate for the difficulty 

 they have in seeing at night ; e. g., the ear in the Owl, and the mouth 

 in the Night-jar ; and there can be no doubt that the prolongation of 

 the nostrils in the family Procellaridce is for the same purpose. The 

 habits of Diomedea, where the tube is reduced to a minimum, are diurnal, 

 except perhaps while the birds are young ; they do not therefore re- 

 quire their sense of smell to be more than ordinarily acute. The various 

 species of Puffinus an&Pelecanoides, too, in which the tube is not so well 

 developed as it is in Procellaria and Thalassidroma, although eminently 

 nocturnal, take their prey chiefly under water, where smell cannot be of 

 much use. The slanting position of their nostrils would also prevent the 

 water being forced into them when diving. The tube is larger in Pro- 

 cellaria gigantea than in any other species of the family, and its ex- 

 tremely voracious appetite makes it appear probable that it requires 

 means for obtaining food superior to any of the others. 



Another point of great interest connected with these birds is the 

 way they sometimes follow a ship for days together, and are sel- 

 dom seen to settle on the water. I have been informed by Lieute- 

 nant "Weld, E. N., that a Cape Pigeon, with a piece of red ribbon round 

 its neck, once followed the ship he was in for 1500 miles, and an albino 

 variety of P. gig ant m followed Mr. Gould's ship for three weeks, and 

 this bird has by no means the same powers of flight as the Albatross. I 

 myself have sometimes seen the same Albatross, or Cape Pigeon, for 

 several days in succession, while the ship has been going from 150 to 

 200 miles in the twenty-four hours, but these are exceptional cases. It 

 is, I believe, the generally received opinion of naturalists that these 

 birds, when seen for several days together, have never slept during the 

 whole period, but have followed the ship night and day. To me, how- 

 ever, it appears incredible that any animal should be able to undergo 

 so much exertion for so long a time without taking rest ; and I hope to 

 show that it is not necessary to suppose that it does do so. Mr. 

 Gould says that birds caught and marked, are generally seen next day, 

 but such is not my experience. I have sometimes marked ten or 

 twelve Cape Pigeons in a day and seldom seen one again. Mr. Gould, 

 however, is quite right when he says that sometimes a marked bird 

 turns up after being absent for two or three days ; and how can this be 

 accounted for by the theory of the birds constantly following the ship ? 



