Chap, viii.] 



DIVING PETRELS. 



I8l 



I saw once about a dozen of these birds swimming together 

 at Royal Sound, but usually they hawk over the sea singly, 

 with a long sweeping flight like that of the albatross. The 

 young are like round balls of grey down, and, as might be 

 expected, have the nostrils much more widely open than the 

 adults. 



Further we found a Stormy Petrel {Oceanitis sp.). It makes 

 a short small hole in the turf at the verge of the cliffs, and 

 lays a white egg, with slight red speckles at one end, large in 

 size in proportion to the bird. 



A more interesting petrel is the diving Procellarid {Peleca- 

 noides ziriuatrix), which is a petrel that has given up the 

 active aerial habits of its allies, and has taken to diving, and 

 has become specially modified by natural selection to suit it 

 for this changed habit, though still a petrel in essential 

 structure. The habits of the bird, which occurs in the Straits 

 of Magellan, are described by Darwin in his Journal.* This 

 bird is to be seen on 

 the surface of the water 

 in Royal Sound when 

 the water is calm, in 

 flocks of very large num- 

 bers. On two days in 

 which excursions were 

 made in the steam pin- 

 nace, the water was seen 

 to be covered with these 

 birds in flocks, extend- 

 ing over acres, which 

 were black with them. 

 The habits of the nor- 

 thern Little Auk are said 

 to be closely similar to 

 those of this bird ; so 

 close is the resemblance, that the whalers have transferred one 

 of their familiar names for the Little Auk to the Diving Petrel. 

 The diving petrels dive with extreme rapidity, and when 

 frightened, get up and flutter along close to the water, and 

 drop and dive again. It is a curious sight to see a whole 

 flock thus taking flight. The birds make holes in the ground 

 like the Prions, and lay an egg, white with a few red specks at 

 one end. They breed in enormous quantities on the islands in 

 Royal Sound. They are readily attracted by a light, and some 

 were caught on board through coming to the ship's lights. 



On one of the digging excursions I found a nest of the 



* "Journal of Researches," p. 290. 



SHEATH-BILL OF FUEGIA. CHIOXIS ALBA. 



