THE PETRELS. 



209 



Thomson well observes, has a close general likeness to the Little Auk, or Rotche (Mergudua alle), of 

 the northern seas. Both of them have a hurried flight ; both of them, while flying, dive into the 

 sea without any interruption in the action of their wings, and also emerge from beneath the surface 

 flying, and they both of them swim with the tail rather deep in the water. But this resemblance 

 does not extend to other particulars of their habits. The Rotche, when breeding, usually flies and 

 .fishes in small flocks of six or a dozen birds, and builds in communities of considerable size, which are 



STOKMY PETREL. 



excessively noisy. Diving Petrels, on the other hand, are more domestic in their mode of living, 

 fishing and flying for the most part in pairs or alone, and building sporadically. They had begun 

 to pair when we reached Kerguelen Island. The first egg was found on the 31st of October. 

 Their burrows are about as small in diameter as the holes of Bank Martins (Cotyle riparia) or 

 Kingfishers (Alcedo hispida). They are made in dry banks and slopes where the ground is easily 

 penetrable, and terminate in an enlarged chamber, on whose floor the egg is deposited. There is no 

 specially-constructed nest. Some of the burrows are branched, but the branches are without terminal 

 enlargements, and do not appear to be put to any use by the birds. Before the egg is laid, both of 

 the parents maybe found in the nest-chamber, and may often be heard moaning in the day-time; 



